标签：HttpServletRequest JavaWeb resp req import servlet javax

JavaWeb

1.Servlet

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
                            http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0"
         metadata-complete="true">
    <!--注册Servlet-->
    <servlet>
        <servlet-name>hello</servlet-name>
        <servlet-class>com.jf.servlet.HelloServlet</servlet-class>
    </servlet>
    <!--Servlet的请求路径-->
    <servlet-mapping>
        <servlet-name>hello</servlet-name>
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>error</servlet-name>
        <servlet-class>com.jf.servlet.ErrorServlet</servlet-class>
        <!--可以自定义后缀实现请求映射，注意*前面不能加项目映射的路径-->
        <!--优先级问题，指定了固有的映射路径优先级最高，如果找不到就会走默认的处理请求-->
    </servlet>
    <servlet-mapping>
        <servlet-name>error</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>
</web-app>

package com.jf.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

public class ErrorServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html");
        resp.setCharacterEncoding("utf-8");
        PrintWriter writer = resp.getWriter();
        writer.print("<h1>404</h1>");
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package com.jf.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class HelloServlet extends HttpServlet {
    public HelloServlet() {
    }

    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("进入doGet方法");
        PrintWriter writer = resp.getWriter();
        writer.print("Hello,Servlet");
    }

    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}

2.ServletContext

web容器在启动的时候，它会为每个web程序都创建一个对应的ServletContext对象，它代表了当前
的web应用:

1.共享数据

我在这个Servet中保存的数据，可以在另外一个servlet中拿到:

package com.jf.servlet;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class HelloServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext context = this.getServletContext();
        String username="张飞";//数据

        context.setAttribute("username",username);//将一个数据保存在了ServletContext中，名字为;username，值username

    }
}

package com.jf.servlet;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class GetServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext context = this.getServletContext();
        String username = (String) context.getAttribute("username");

        resp.setContentType("text/html");
        resp.setCharacterEncoding("utf-8");
        resp.getWriter().print("名字"+username);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

<servlet>
        <servlet-name>hello</servlet-name>
        <servlet-class>com.jf.servlet.HelloServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>hello</servlet-name>
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>
<servlet>
    <servlet-name>getc</servlet-name>
    <servlet-class>com.jf.servlet.GetServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>getc</servlet-name>
    <url-pattern>/getc</url-pattern>
</servlet-mapping>

2.获取初始化参数

<!--配置一些web应用初始化参数-->
<context-param>
    <param-name>url</param-name>
    <param-value>jdbc:mysql://localhost:3306/mybatis</param-value>
</context-param>

package com.jf.servlet;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class ServletDemo03 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext context = this.getServletContext();
        String url = context.getInitParameter("url");
        resp.getWriter().print(url);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

<servlet>
    <servlet-name>gp</servlet-name>
    <servlet-class>com.jf.servlet.ServletDemo03</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>gp</servlet-name>
    <url-pattern>/gp</url-pattern>
</servlet-mapping>

3.请求转发

package com.jf.servlet;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class ServletDemo04 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext context = this.getServletContext();
        context.getRequestDispatcher("/gp").forward(req,resp);//请求转发
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

<servlet>
    <servlet-name>sd4</servlet-name>
    <servlet-class>com.jf.servlet.ServletDemo04</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>sd4</servlet-name>
    <url-pattern>/sd4</url-pattern>
</servlet-mapping>

4.读取资源文件

Properties
在java日录下新建properties
在resources日录下新建properties
发现:都被打包到了同一个路径下:classes，我们俗称这个路径为classpath:

maven由于他的约定大于配置，我们之后可以能遇到我们写的配置文件，无法被导出或者生效的问题，解决方案:

需要一个文件流

username=root
password=123456

<!--在build中配置resources，来防止资源导出失败的问题-->
<build>
    <resources>
        <resource>
            <directory>src/main/resources</directory>
            <includes>
                <include>**/*.properties</include>
                <include>**/*.xml</include>
            </includes>
            <filtering>true</filtering>
        </resource>
        <resource>
            <directory>src/main/java</directory>
            <includes>
                <include>**/*.properties</include>
                <include>**/*.xml</include>
            </includes>
            <filtering>true</filtering>
        </resource>
    </resources>
</build>

package com.jf.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class ServletDemo05 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        InputStream is = this.getServletContext().getResourceAsStream("/WEB-INF/classes/db.properties");
        Properties prop = new Properties();
        prop.load(is);

        String user = prop.getProperty("username");
        String pwd = prop.getProperty("password");
        resp.getWriter().print(user+":"+pwd);

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

<servlet>
    <servlet-name>sd5</servlet-name>
    <servlet-class>com.jf.servlet.ServletDemo05</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>sd5</servlet-name>
    <url-pattern>/sd5</url-pattern>
</servlet-mapping>

3.HttpServletResponse

web服务器接收到客户端的http请求，针对这个请求，分别创建一个代表请求的HttpServletRequest对象，代表响应的一个HttpServletResponse。
如果要获取客户端请求过来的参数:找HttpServletRequest

如果要给客户端响应一些信息:找HttpServletResponse

1.下载文件

package com.jf.servlet;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URLEncoder;

public class FileServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        1.要获取下载文件的路径
        String realPath = "D:\\code\\maven\\java-14-maven\\response\\src\\main\\resources\\zhangsan.png";
        System.out.println("下载文件的路径:"+realPath);
//        2.下载的文件名是啥
        String fileName = realPath.substring(realPath.lastIndexOf("\\") + 1);
//        3.设置想办法让浏览器能够支持下载我们需要的东西,中文文件名URLEncoder.encode编码，否则有可能乱码
        resp.setHeader("Content-Disposition","attachment;filename="+ URLEncoder.encode(fileName,"UTF-8"));
//        4.获取下载文件的输入流
        FileInputStream in = new FileInputStream(realPath);
//        5.创建缓冲区
        int len=0;
        byte[] buffer = new byte[1024];
//        6.获取OutputStream对象
        ServletOutputStream out = resp.getOutputStream();
//        7.将FileOutputstream流写入到buffer缓冲区,使用Outputstream将缓冲区中的数据输出到客户端!
        while ((len=in.read(buffer))>0){
            out.write(buffer,0,len);
        }
        in.close();
        out.close();
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

<servlet>
        <servlet-name>filedown</servlet-name>
        <servlet-class>com.jf.servlet.FileServlet</servlet-class>
    </servlet>
<servlet-mapping>
    <servlet-name>filedown</servlet-name>
    <url-pattern>/down</url-pattern>
</servlet-mapping>

2.验证码功能

package com.jf.servlet;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

public class ImageServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //如何让浏览器5秒刷新一次
        resp.setHeader("refresh","5");
        //在内存中创建一个图片
        BufferedImage image = new BufferedImage(80,20,BufferedImage.TYPE_INT_RGB);
        //得到图片
        Graphics2D g = (Graphics2D) image.getGraphics();//笔
        //设置图片的背景颜色
        g.setColor(Color.white);
        g.fillRect(0,0,80,20);
        //给图片写数据
        g.setColor(Color.BLUE);
        g.setFont(new Font(null,Font.BOLD,20));
        g.drawString(makeNum(),0,20);
        //告诉浏览器，这个请求用图片的方式打开
        resp.setContentType("image/jpg");
        //浏览器有缓存，不让浏览器缓存
        resp.setDateHeader("expires",-1);
        resp.setHeader("Cache-Control","no-Cache");
        resp.setHeader("Pragma","no-Cache");
        //把图片写给浏览器
        ImageIO.write(image,"jpg",resp.getOutputStream());
    }

    //生成随机数
    private String makeNum(){
        Random random = new Random();
        String num = random.nextInt(9999999) + "";
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < 7-num.length(); i++) {
            sb.append("0");
        }
       num = sb.toString() + num;
        return num;
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

<servlet>
    <servlet-name>ImageServlet</servlet-name>
    <servlet-class>com.jf.servlet.ImageServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>ImageServlet</servlet-name>
    <url-pattern>/img</url-pattern>
</servlet-mapping>

3.重定向

B一个web资源收到客户端A请求后，B会通知A客户端去访问另外一个web资源C，这个过程就叫重定向

常见场景：

用户登录

void sendRedirect(String var1) throws IOException;

测试：

package com.jf.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class RedirectServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//       resp.setHeader(" Location","/response_war/img");
//       resp.setStatus(302);
       resp.sendRedirect("/response_war/img");

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

重定向和转发的不同点：

相同点：

页面都会跳转
不同点：

请求转发的url不会发生变化

重定向时候，url地址栏会发生变化

Demo:

package com.jf.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class Request extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //处理请求
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        System.out.println(username+":"+password);
        //重定向时候一定注意，路径问题，否则出现404
        resp.sendRedirect("/response_war/success.jsp");
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

<html>
<body>
<!--这里提交的路径，需要寻找项目的路径-->
<%--${pageContext.request.contextPath}代表当前的项目--%>
<h2>Hello World!</h2>
<form action="${pageContext.request.contextPath}/login" method="get">
    用户名：<input type="text" name="username"><br>
    密码：<input type="password" name="password"><br>
    <input type="submit">
</form>
</body>
</html>

<%--
  Created by IntelliJ IDEA.
  User: hjf
  Date: 2024/8/19
  Time: 16:50
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
    <h1>Success</h1>
</head>
<body>

</body>
</html>

4.HttpServletRequest

HttpServletRequest代表客户端的请求，用户通过http协议访问服务器，HTTP请求中的所有的信息会被封装到HttpServletRequest，通过这个HttpServletRequest方法，获得客户端的所有信息。

获取参数，请求转发：

package com.jf.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.Array;
import java.util.Arrays;

public class LoginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        resp.setCharacterEncoding("utf-8");
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        String[] hobbies = req.getParameterValues("hobbies");
        System.out.println("===============");
        System.out.println(username);
        System.out.println(password);
        System.out.println(Arrays.toString(hobbies));
        System.out.println("======================");

        //通过请求转发
        //这里的/代表当前的web应用
        req.getRequestDispatcher("/success.jsp").forward(req,resp);

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>登录</title>
</head>
<body>
<div>
    <form action="${pageContext.request.contextPath}/login" method="post">
        用户名：<input type="text" name="username"><br>
        密码：<input type="password" name="password"><br>
        爱好：
        <input type="checkbox" name="hobbies" value="电影">电影
        <input type="checkbox" name="hobbies" value="代码">代码
        <input type="checkbox" name="hobbies" value="旅游">旅游
        <input type="checkbox" name="hobbies" value="独处">独处
        <br>
        <input type="submit">
    </form>
</div>
</body>
</html>

<%--
  Created by IntelliJ IDEA.
  User: hjf
  Date: 2024/8/19
  Time: 17:33
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h1>登录成功</h1>
</body>
</html>

5.Cookie Session

5.1 保存回话的两种技术

客户端技术（响应，请求）

session

服务端技术，利用这个技术，可以保存用户的会话信息

1.从请求中拿到cookie信息

2.服务器响应给客户端cookie

一个Cookie只能保存一个信息
一个web站点可以给浏览器发送多个cookie，最多可以保存20个cookie
Cookie大小有限制为4kb
300个cookie浏览器上限

删除Cookie;

不设置有效期，关闭浏览器，自动失效
设置有效期为0

编码和解码

URLEncoder.encode("张飞","utf-8")
URLDecoder.decode(cookie.getValue(),"utf-8")

package com.jf.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;

public class CookieDemo01 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //解决中文乱码问题
        req.setCharacterEncoding("utf-8");
        resp.setCharacterEncoding("utf-8");

        PrintWriter out = resp.getWriter();
        //Cookie，服务器从客户端拿取
        Cookie[] cookies = req.getCookies();//这里返回数组，说明存在多个cookie
        //判断cookie是否存在
        if(cookies!=null){
            //如果存在
            out.write("你上一次访问的时间是：");
            for (int i = 0; i < cookies.length; i++) {
                Cookie cookie = cookies[i];
                //获取cookie的名字
                if(cookie.getName().equals("lastLoginTime")){
                    //获取cookie中的值
                    long lastLoginTime = Long.parseLong(cookie.getValue());
                    Date date = new Date(lastLoginTime);
                    out.write(date.toLocaleString());
                }

            }
        }else {
            out.write("这是你第一次访问本站");
        }
        //服务给客户端响应一个cookie

        Cookie cookie = new Cookie("lastLoginTime",System.currentTimeMillis()+"");
        //cookie有效期为1天
        cookie.setMaxAge(24*60*60);
        resp.addCookie(cookie);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

package com.jf.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.util.Date;

//中文数据传递
public class CookieDemo03 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //解决中文乱码问题
        req.setCharacterEncoding("utf-8");
        resp.setCharacterEncoding("utf-8");
        //Cookie，服务器从客户端拿取
        Cookie[] cookies = req.getCookies();//这里返回数组，说明存在多个cookie
        PrintWriter out = resp.getWriter();
        //判断cookie是否存在
        if(cookies!=null){
            //如果存在
            out.write("你上一次访问的时间是：");
            for (int i = 0; i < cookies.length; i++) {
                Cookie cookie = cookies[i];
                //获取cookie的名字
                if(cookie.getName().equals("name")){
                    //解码
                    out.write(URLDecoder.decode(cookie.getValue(),"utf-8"));
                }

            }
        }else {
            out.write("这是你第一次访问本站");
        }
        //编码
        Cookie cookie = new Cookie("name", URLEncoder.encode("张飞","utf-8"));
        resp.addCookie(cookie);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}

5.3 Session（重点）

什么是session

服务器会给每一个用户创建一个Session对象
一个session 独占一个浏览器，只要浏览器没有关闭，这个session就存在
用户登录网站，整个网站都可以访问----》保存用户的信息

session和cookie的区别

cookie就是把用户的数据写给浏览器，浏览器保存（可以保存多个）
session把用户的数据写到用户独占Session中，服务器保存（保存重要的信息，减少服务器资源的浪费）
session对象是由服务创建

使用场景

保存一个登陆用户的信息
购物车信息
在整个网站中经常使用的数据，将它保存在Session中；

package com.jf.servlet;

import com.jf.pojo.Person;

import javax.servlet.ServletException;
import javax.servlet.http.*;
import java.io.IOException;

public class SessionDemo01 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //解决乱码问题
        resp.setCharacterEncoding("utf-8");
        req.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf-8");

        //得到session
        HttpSession session = req.getSession();
        //给session存信息
        session.setAttribute("name",new Person("张飞",15));
        //获取session的id
        String sessionId = session.getId();
        //判断Seesion是不是新创建的
        if(session.isNew()){
            resp.getWriter().write("session创建成功,ID:"+sessionId);
        }else {
            resp.getWriter().write("session已经在服务器中存在了,ID:"+sessionId);
        }
        //session创建的时候做了：
//        Cookie cookie = new Cookie("JSESSIONID",sessionId);
//        resp.addCookie(cookie);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

得到session

package com.jf.servlet;

import com.jf.pojo.Person;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

public class SessionDemo02 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //解决乱码问题
        resp.setCharacterEncoding("utf-8");
        req.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf-8");

        //得到session
        HttpSession session = req.getSession();
        Person person = (Person) session.getAttribute("name");
        System.out.println(person.toString());
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

手动注销

package com.jf.servlet;

import com.jf.pojo.Person;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

public class SessionDemo03 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        HttpSession session = req.getSession();
        session.removeAttribute("name");
        session.invalidate();//注销
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

自动注销在web.xml中配置

<!--设置session的失效时间-->
<session-config>
    <!--15分钟后失效，以分钟为单位-->
    <session-timeout>15</session-timeout>
</session-config>

6.JSP

什么是jsp

java server page:java服务器端页面，也和servlet一样，用于动态Web页面

最大的特点：

写JSP和HTML一样
区别：
- HTML只给用户提供静态的数据
- JSP页面可以嵌入java代码，为用户提供动态数据

浏览器向服务器发送请求，不管访问什么资源，其实都是访问Servlet

JSP最终也会被装换一个java类

//初始化
public void _jspInit() {
  }
//销毁
public void _jspDestroy() {
  }
//JSPService
public void _jspService(HttpServletRequest request,HttpServletResponse response)

    final javax.servlet.jsp.PageContext pageContext;//页面上下文
    final javax.servlet.ServletContext application;//applicationContext
    final javax.servlet.ServletConfig config;//config
    javax.servlet.jsp.JspWriter out = null;//out
    final java.lang.Object page = this;//page:当前页
    javax.servlet.jsp.JspWriter _jspx_out = null;
    javax.servlet.jsp.PageContext _jspx_page_context = null;
    HttpServletRequest request//请求
    HttpServletResponse response//响应

输出页面前增加的代码

	  response.setContentType("text/html; charset=UTF-8");//设置响应的类型
      pageContext = _jspxFactory.getPageContext(this, request, response,
      			null, false, 8192, true);
      _jspx_page_context = pageContext;
      application = pageContext.getServletContext();
      config = pageContext.getServletConfig();
      out = pageContext.getOut();
      _jspx_out = out;

以上的这些对象都可以在JSP中使用

在JSP页面中，只要是JAVA代码就会原封不动的输出

如果是HTML代码，就会封装为：

out.write("<html>\r\n")

这样的格式，输出到前端

6.1 JSP基础语法

JSP表达式

<%--  JSP表达式
  作用：用来将程序的输出，输出到客户端
--%>
  <%= new java.util.Date()%>

JSP脚本片段

<%--  JSP脚本片段--%>
<%
  int sum = 0;
  for (int i = 0; i <=100; i++) {
    sum+=i;
  }
  out.print("<h1>Sum="+sum+"</h1>");
%>

JSP片段的再实现

<%--  JSP脚本片段--%>
<%
  int sum = 0;
  for (int i = 0; i <=100; i++) {
    sum+=i;
  }
  out.print("<h1>Sum="+sum+"</h1>");
%>
<%
  int x=10;
  out.println(x);
%>
<%
  int y=2;
  out.println(y);
%>
<%--在代码中嵌入HTML代码--%>
<%
  for (int i = 0; i <=5; i++) {
%>
<h1>hello world</h1>
<%
  }
%>

JSP声明

<%!
  static {
    System.out.println("Loading Servlet!");
  }
  private int globVar= 0 ;
  public void k(){
    System.out.println("进入了K方法");
  }
%>

JSP声明：会被编译到JSP生成Java的类中，其他的就会被生成到_jspService方法中。

JSP注释不会在客户端中显示，html就会显示。

6.2 JSP指令

jsp导包

<%@ page import="java.util.Date" %>

jsp定制错误页面

方法一：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page errorPage="error/500.jsp" %>
<html>
<%--定制错误页面--%>
<head>
    <title>Title</title>
</head>
<body>
<%
    int x =1/0;
%>
</body>
</html>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<img src="../img/500.png" alt="500">
</body>
</html>

方法二：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<html>
<%--定制错误页面--%>
<head>
    <title>Title</title>
</head>
<body>
<%
    int x =1/0;
%>
</body>
</html>

在web.xml中

<error-page>
    <error-code>500</error-code>
    <location>/error/500.jsp</location>
</error-page>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<img src="../img/500.png" alt="500">
</body>
</html>

JSP拼接页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<html>
<head>
    <title>Title</title>
</head>
<body>
<%--@include会将两个页面合二为一--%>
<%@include file="common/header.jsp"%>
<h1>网页主体</h1>
<%@include file="common/footer.jsp"%>

<hr>
<%--JSP标签
jsp:include：拼接页面，本质是三个
--%>
<jsp:include page="common/header.jsp"/>
<h1>网页主体</h1>
<jsp:include page="common/footer.jsp"/>
</body>
</html>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<h1>我是footer</h1>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h1>我是header</h1>
</body>
</html>

6.3 9大内置对象

PageContext 存东西
Request 存东西
Response
Session 存东西
Application [ServletContext] 存东西
config [ServletConfig]
out
page
exception

Request ：客户端向服务器发送请求，产生的数据，用户看完就没用了，比如：新闻

Session ：客户端向服务器发送请求，产生的数据，用户用完一会还有用，比如购物车

Application：客户端向服务器发送请求，产生的数据，一个用户用完了，其他用户还可能使用，比如聊天数据

常见场景：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<%
    pageContext.setAttribute("name1","张飞1号");//保存的数据只在一个页面中有效
    request.setAttribute("name2","张飞2号");//保存的数据只在一次请求中有效，请求转发会携带这个数据
    session.setAttribute("name3","张飞3号");//保存的数据只在一次会话中有效，从打开浏览器到关闭浏览器
    application.setAttribute("name4","张飞4号");//保存的数据只在服务器中有效，从打开服务器到关闭服务器
%>
<%--脚本片段的代码，会被原封不动生成到...jsp.java
    要求：这里的代码，必须保证Java语法的正确性
--%>
<%
    //从pageContext取出，我们通过寻找的方式来
    //从底层到高层（作用域）page-->request-->session-->application
    String name1 = (String) pageContext.findAttribute("name1");
    String name2 = (String) pageContext.findAttribute("name2");
    String name3 = (String) pageContext.findAttribute("name3");
    String name4 = (String) pageContext.findAttribute("name4");
    String name5 = (String) pageContext.findAttribute("name5");
    pageContext.forward("/pageDemo03.jsp");
%>
<%--使用EL表达式输出--%>
<h1>取出的值：</h1>
<h2>${name1}</h2>
<h2>${name2}</h2>
<h2>${name3}</h2>
<h2>${name4}</h2>
<h2><%= name5%></h2>
</body>
</html>

7 JSP标签，JSTL标签，EL表达式

<!--            jsp表达式的依赖-->
            <groupId>javax.servlet.jsp.jstl</groupId>
            <artifactId>jstl-api</artifactId>
            <version>1.2</version>
        </dependency>
        <dependency>
<!--         standard标签   -->
            <groupId>taglibs</groupId>
            <artifactId>standard</artifactId>
            <version>1.1.2</version>
        </dependency>

EL表达式：${}

作用：

获取数据
执行运算
获取web开发的常用对象

JSP标签：

<jsp:forward page="jspTag2.jsp">
    <jsp:param name="name" value="js"/>
    <jsp:param name="age" value="15"/>
</jsp:forward>

JSTL表达式：

JSTL标签的使用是为了弥补HTML的不足，它自定义了许多标签，标签的代码和java代码一样

核心标签：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h4>测试</h4>
<form action="coreif.jsp" method="get">
<%--    EL表达式获取表单中的数据
    ${param.参数名}
--%>
    <input type="text" name="username" value="${param.username}">
    <input type="submit" value="登录">
</form>
<%--判断如果提交的用户是管理员，则登录成功--%>
<c:if test="${param.username=='admin'}" var="isAdmin">
    <c:out value="管理员欢迎您"></c:out>
</c:if>
<c:out value="${isAdmin}"></c:out>
</body>
</html>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<%--定义一个变量score,值为85--%>
<c:set  var="score" value="85"></c:set>
<c:choose>
    <c:when test="${score>=90}">
        你的成绩为优秀
    </c:when>
    <c:when test="${score>=80}">
        你的成绩为良好
    </c:when>
</c:choose>
</body>
</html>

<%@ page import="java.util.ArrayList" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<%
    ArrayList<String> people = new ArrayList<>();
    people.add(0,"张飞");
    people.add(1,"张2");
    people.add(2,"张3");
    people.add(3,"张4");
    request.setAttribute("list",people);
%>
<%--
var 每一次遍历的变量
items 要遍历的对象
begin 哪里开始
end 到哪里
step 步长
--%>
<c:forEach var="people" items="${list}">
    <c:out value="${people}"></c:out>
</c:forEach>
<hr>
<c:forEach var="people" items="${list}" begin="1" end="2" step="1">
    <c:out value="${people}"></c:out>
</c:forEach>
</body>
</html>

8 MVC三层架构

Model

业务处理：业务逻辑（Service）
数据持久层：CRUD (Dao)

View

展示数据
提供链接发起Servlet请求（a,img,form...）

Controller

接收用户的请求：（req:请求参数，Session信息...）
交给业务层处理对应的代码
控制视图的跳转

登录-->接收用户的登录请求-->处理用户的请求（获取用户登录的参数,username,password）-->交给业务层处理登录业务（判断用户名和密码是否正确：事务）-->Dao层查询用户名和密码是否正确-->数据库

9 Filter

Filter:过滤器，用来过滤网站的数据

用来处理中文乱码
用来登录验证

步骤：

1.导包

2.编写过滤器

package com.jf.filter;

import javax.servlet.*;
import java.io.IOException;

public class CharacterEncodingFilter implements Filter {
    //初始化 web服务器启动，就已经初始化了
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("CharacterEncodingFilter已经初始化了");
    }

    //chain :链
    /*
    * 1.过滤中的所有的代码，在过滤特定请求的时候都会执行
    * 2.必须要让过滤器继续同行
    * chain.doFilter(request,response);
    * */
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=UTF-8");
        System.out.println("CharacterEncodingFilter执行前");
        chain.doFilter(request,response);//让我们的请求继续执行，如果不写，程序就会停止
        System.out.println("CharacterEncodingFilter执行后");
    }

    //销毁 web服务器停止了，过滤就会销毁
    @Override
    public void destroy() {
        System.out.println("CharacterEncodingFilter销毁");
    }
}

在web.xml中设置：

<filter>
    <filter-name>CharacterEncodingFilter</filter-name>
    <filter-class>com.jf.filter.CharacterEncodingFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>CharacterEncodingFilter</filter-name>
    <url-pattern>/servlet/*</url-pattern>
</filter-mapping>

10.监听器

1.编写监听器接口

package com.jf.listener;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

//统计网站的在线人数：
public class OnlineCountListener implements HttpSessionListener {
    //创建session监听
    //一旦创建session就会触发一次事件
    @Override
    public void sessionCreated(HttpSessionEvent se) {
        ServletContext ctx = se.getSession().getServletContext();
        System.out.println(se.getSession().getId());
        Integer onlineCount = (Integer) ctx.getAttribute("OnlineCount");
        if(onlineCount==null){
            onlineCount = new Integer(1);
        }else {
            int count= onlineCount.intValue();
            onlineCount= new Integer(count+1);
        }
        ctx.setAttribute("OnlineCount",onlineCount);
    }

    //销毁session监听
    //一旦销毁session就会触发一次事件
    @Override
    public void sessionDestroyed(HttpSessionEvent se) {
        ServletContext ctx = se.getSession().getServletContext();


        Integer onlineCount = (Integer) ctx.getAttribute("OnlineCount");
        if(onlineCount==null){
            onlineCount = new Integer(0);
        }else {
            int count= onlineCount.intValue();
            onlineCount= new Integer(count-1);
        }
        ctx.setAttribute("onlineCount",onlineCount);
    }
    /*
    * session销毁
    * 手动销毁： se.getSession().invalidate();
    * 自动销毁在web.xml中设置：<session-config>
                   <session-timeout>1</session-timeout>
              </session-config>
    * */
}

2.在web.xml注册监听器

<listener>
    <listener-class>com.jf.listener.OnlineCountListener</listener-class>
</listener>

11.监听器和过滤器的常见应用

在GUI中监听器的应用：

package com.jf.listener;

import java.awt.*;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;

public class TestPanel {
    public static void main(String[] args) {
        Frame frame = new Frame("窗口关闭");
        Panel panel = new Panel(null);
        frame.setLayout(null);
        frame.setBounds(300,300,500,500);
        frame.setBackground(new Color(0,0,255));
        panel.setBounds(50,50,300,300);
        panel.setBackground(new Color(0,255,0));
        frame.add(panel);
        frame.setVisible(true);
        //监听事件，监听关闭事件
        frame.addWindowListener(new WindowListener() {
            @Override
            public void windowOpened(WindowEvent e) {
                System.out.println("打开");
            }

            @Override
            public void windowClosing(WindowEvent e) {
                System.out.println("关闭img");
                System.exit(0);
            }

            @Override
            public void windowClosed(WindowEvent e) {
                System.out.println("关闭ed");
            }

            @Override
            public void windowIconified(WindowEvent e) {

            }

            @Override
            public void windowDeiconified(WindowEvent e) {

            }

            @Override
            public void windowActivated(WindowEvent e) {
                System.out.println("激活");
            }

            @Override
            public void windowDeactivated(WindowEvent e) {
                System.out.println("未激活");
            }
        });
    }
}

用户登录之后才能进入主页，用户注销后就不能进入主页

1.用户登录之后，向session中放入用户的数据

2.进入主页的时候判断用户是否登录

package com.jf.listener;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class SysFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) resp;
        if(request.getSession().getAttribute("USER_SESSION")==null){
            response.sendRedirect("/error.jsp");
        }
        chain.doFilter(request,response);
    }

    @Override
    public void destroy() {

    }
}

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<form action="/servlet/login" method="post">
    <input type="text" name="username">
    <input type="submit">
</form>
</body>
</html>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h1>错误</h1>
<h1>没有权限，密码错误</h1>
<p><a href="/Login.jsp">返回登录页面</a></p>
</body>
</html>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>

<h1>主页</h1>
<p><a href="/servlet/logout">注销</a></p>
</body>
</html>

package com.jf.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class LoginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取前端请求的参数
        String username = req.getParameter("username");
        if(username.equals("admin")){//登录成功
            req.getSession().setAttribute("USER_SESSION",req.getSession().getId());
            resp.sendRedirect("/sys/success.jsp");
        }else {//登录失败
            resp.sendRedirect("/error.jsp");
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

package com.jf.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class LogoutServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        Object user_session = req.getSession().getAttribute("USER_SESSION");
        if(user_session!=null){
            req.getSession().removeAttribute("USER_SESSION");
            resp.sendRedirect("/Login.jsp");
        }else {
            resp.sendRedirect("/Login.jsp");
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

12.JDBC

JDBC:java连接数据库

需要jar包：

java.sql
javax.sql
mysql-conneter-java

package com.jf.test;

import java.sql.*;

public class TestJdbc {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        //解决中文乱码useUnicode=true&characterEncoding=utf-8
        String url = "jdbc:mysql://localhost:3306/jdbc?useUnicode=true&characterEncoding=utf-8&useSSL=true";
        String username = "root";
        String password = "123456";
        //1.加载驱动
        Class.forName("com.mysql.jdbc.Driver");
        //2.连接数据库
        Connection connection = DriverManager.getConnection(url, username, password);
        //3.向数据库发送sql的对象
        Statement statement = connection.createStatement();
        //4.编写sql
        String sql="select * from users";
        //5.执行sql,返回一个rs:结果集
        ResultSet rs = statement.executeQuery(sql);
        while (rs.next()){
            System.out.println("id="+rs.getObject("id"));
            System.out.println("name="+rs.getObject("name"));
            System.out.println("password="+rs.getObject("password"));
            System.out.println("email="+rs.getObject("email"));
            System.out.println("birthday="+rs.getObject("birthday"));
        }
        //6.关闭连接，释放资源 先开后关
        rs.close();
        statement.close();
        connection.close();

    }
}

预编译sql

package com.jf.test;

import java.sql.*;

public class TestJdbc2 {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        //解决中文乱码useUnicode=true&characterEncoding=utf-8
        String url = "jdbc:mysql://localhost:3306/jdbc?useUnicode=true&characterEncoding=utf-8&useSSL=true";
        String username = "root";
        String password = "123456";
        //1.加载驱动
        Class.forName("com.mysql.jdbc.Driver");
        //2.连接数据库
        Connection connection = DriverManager.getConnection(url, username, password);
        //3.编写sql
        String sql="insert into users(id, name, password, email, birthday) values (?,?,?,?,?)";
        //4.预编译
        PreparedStatement preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setInt(1,5);//给第一个占位符?的值赋值为1
        preparedStatement.setString(2,"java张三");//给第二个占位符?的值赋值为java张三
        preparedStatement.setString(3,"123456");//给第三个位符?的值赋值为123456
        preparedStatement.setString(4,"[email protected]");//给第四个占位符?的值赋值为[email protected]
        preparedStatement.setDate(5,new Date(new java.util.Date().getTime()));//给第五个占位符?的值赋值为new Date(new java.util.Date().getTime())
        //5.执行sql
        int i = preparedStatement.executeUpdate();
        if(i>0){
            System.out.println("插入成功");
        }
        preparedStatement.close();
        connection.close();

    }
}

junit单元测试

依赖：

<!--        单元测试-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

简答使用

@Test注解只有在方法上有效，只要加了这个注解的方法，就可以直接使用

@Test
public void test(){
    System.out.println("hello");
}

事务：

package com.jf.test;

import org.junit.Test;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class TestJdbc3 {
    @Test
    public void test(){
        //解决中文乱码useUnicode=true&characterEncoding=utf-8
        String url = "jdbc:mysql://localhost:3306/jdbc?useUnicode=true&characterEncoding=utf-8&useSSL=true";
        String username = "root";
        String password = "123456";
        Connection connection = null;
        //1.加载驱动
        try {
            Class.forName("com.mysql.jdbc.Driver");

        //2.连接数据库
         connection = DriverManager.getConnection(url, username, password);
        //3.通知数据库开启事务false开启
        connection.setAutoCommit(false);
        String sql="update account set money=money-100 where name='A'";
        connection.prepareStatement(sql).executeUpdate();
        //4.制作错误
        //int i = 1/0;
        String sql2="update account set money=money+100 where name='B'";
        connection.prepareStatement(sql2).executeUpdate();
        connection.commit();//以上两条SQL都执行成功了，就提交事务
        System.out.println("提交成功");
        } catch (Exception e) {
            try {
                //如果出现异常，就通知数据库回滚事务
                connection.rollback();
            } catch (SQLException e1) {
                e1.printStackTrace();
            }
            e.printStackTrace();
        }finally {
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

13.邮件发送

import com.sun.mail.util.MailSSLSocketFactory;

import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import java.security.GeneralSecurityException;
import java.util.Properties;

public class Test {
    //简单邮件：没有附件和图片，纯文本邮件
    //复杂邮件：有附件和图片


    //要发送邮件，需要获得协议和支持，开启服务POP3/STMP
    //jlljptqkgezoihic
    public static void main(String[] args) throws Exception {
        Properties prop = new Properties();
        prop.setProperty("mail.host","smtp.qq.com");
        prop.setProperty("mail.transport.protocol","smtp");
        prop.setProperty("mail.smtp.auth","true");//验证用户密码

        MailSSLSocketFactory sf =new MailSSLSocketFactory();
        sf.setTrustAllHosts(true);
        prop.put("mail.smtp.ssl.enable","true");
        prop.put("mail.smtp.ssl.socketFactory",sf);

        //使用JavaMial发送邮件的5个步骤
        //1.创建定义整个应用程序所需的环境信息的Session对象
        Session session = Session.getDefaultInstance(prop, new Authenticator() {
            @Override
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication("[email protected] ", "jlljptqkgezoihic");
            }
        });
        session.setDebug(true);
        //2.通过session获得transport对象
        Transport ts = session.getTransport();
        //3.使用邮箱的用户名和授权码连上邮件服务器
        ts.connect("smtp.qq.com","[email protected]","jlljptqkgezoihic");
        //4.创建邮件
        MimeMessage message = new MimeMessage(session);
        message.setFrom(new InternetAddress("[email protected]"));//发件人
        message.setRecipient(Message.RecipientType.TO,new InternetAddress("[email protected]"));//收件人
        message.setSubject("HELLO");
        message.setContent("<h1 style='color:red'>你好</h1>","text/html;charset=UTF-8");
        //5.发送邮件
        ts.sendMessage(message,message.getAllRecipients());
        //6.关闭链接
        ts.close();

    }


}

标签：HttpServletRequest,JavaWeb,resp,req,import,servlet,javax
From： https://www.cnblogs.com/huangjiangfei/p/18397073

JavaWeb

JavaWeb

1.Servlet

2.ServletContext

1.共享数据

2.获取初始化参数

3.请求转发

4.读取资源文件

3.HttpServletResponse

1.下载文件

2.验证码功能

3.重定向

4.HttpServletRequest

获取参数，请求转发：

5.Cookie Session

5.1 保存回话的两种技术

5.3 Session（重点）

6.JSP

6.1 JSP基础语法

6.2 JSP指令

6.3 9大内置对象

7 JSP标签，JSTL标签，EL表达式

8 MVC三层架构

9 Filter

10.监听器

11.监听器和过滤器的常见应用

12.JDBC

13.邮件发送

相关文章

赞助商

阅读排行

JavaWeb

JavaWeb

1.Servlet

2.ServletContext

1.共享数据

2.获取初始化参数

3.请求转发

4.读取资源文件

3.HttpServletResponse

1.下载文件

2.验证码功能

3.重定向

4.HttpServletRequest

获取参数，请求转发：

5.Cookie Session

5.1 保存回话的两种技术

5.2 cookie

5.3 Session（重点）

6.JSP

6.1 JSP基础语法

6.2 JSP指令

6.3 9大内置对象

7 JSP标签，JSTL标签，EL表达式

8 MVC三层架构

9 Filter

10.监听器

11.监听器和过滤器的常见应用

12.JDBC

13.邮件发送

相关文章

赞助商

阅读排行