9 - IPS99技术分享

标签： String request connection jsp password pst

新建项目

在webapp上右键添加新的目录起名为lib

导包，将jar包粘贴到lib目录中，右键jar包选择添加为库

连接tomcat并导入工件

两个工件都要导入

后连接数据库，输入账号密码后连接即可

在数据库中创建一个新的表

在webapp中右键新建jsp文件完成操作

index.jsp中写主页面，点击实现增删改查的进入

<%@ page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
    <title>主页面</title>
</head>
<body>
    <h2>主界面</h2>
    <a href="zengshu.jsp" target="_self">
        <button>增</button>
    </a>
    <a href="shanshu.jsp" target="_self">
        <button>删</button>
    </a>
    <a href="gaishu1.jsp" target="_self">
        <button>改</button>
    </a>
    <a href="chashu.jsp" target="_self">
        <button>查</button>
    </a>
</body>
</html>

zengshu.jsp中实现要增加的课程内容的输入

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<form action="zeng.jsp">
    <label for="k">课程:</label>
    <input type="text" id="k" name="k"><br>
    <label for="teacher">老师:</label>
    <input type="text" id="teacher" name="teacher"><br>
    <label for="address">教室:</label>
    <input type="text" id="address" name="address"><br>
    <input type="reset" value="重置">
    <input type="submit" value="提交">
</form>
</body>
</html>

输入之后点击提交进入zeng.jsp，连接数据库并向库内插入已输入的内容，username为数据库账号，password为数据库密码，try catch中为连接数据库并插入的格式

<%@ page import="java.sql.*" %>
<%@ page import="java.nio.channels.Selector" %>
<%@ page import="java.util.Arrays" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<%
    String k=request.getParameter("k");
    String teacher=request.getParameter("teacher");
    String address=request.getParameter("address");
    try {
        Class.forName("com.mysql.cj.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/test";
        String username = "root";
        String password = "123456";
        Connection connection = DriverManager.getConnection(url, username, password);
        Statement statement = connection.createStatement();
        String sql = "insert into class(k,teacher,address) values(?,?,?)";
        PreparedStatement pst = connection.prepareStatement(sql);
        pst.setString(1, k);
        pst.setString(2, teacher);
        pst.setString(3, address);
        String n="添加完成";
        request.setAttribute("n",n);
        pst.executeUpdate();
        connection.close();
        pst.close();
    } catch (ClassNotFoundException e) {
        throw new RuntimeException(e);
    }
%>
<head>
    <title>Title</title>
</head>
<body>
<font size=2>
    ${n}
</font><br>
<a href="index.jsp" target="_self">
    <button>返回主界面</button>
</a>
</body>
</html>

shanshu.jsp为输入要删除的内容

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<form action="shan.jsp">
    <label for="k">课程:</label>
    <input type="text" id="k" name="k"><br>
    <input type="reset" value="重置">
    <input type="submit" value="提交">
</form>
</body>
</html>

提交后进入shan.jsp，连接数据库和增加操作一样，根据

String sql = "";

引号内的内容不同实现不同的功能，删除的格式为from后接表名，where后接要删除的内容

<%@ page import="java.sql.*" %>
<%@ page import="java.nio.channels.Selector" %>
<%@ page import="java.util.Properties" %>
<%@ page import="java.io.FileInputStream" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<%
    String k=request.getParameter("k");
    String n = null;
    String driverClass="com.mysql.cj.jdbc.Driver";
    String url="jdbc:mysql://localhost:3306/test";
    String user="root";
    String password="zljzy962464";
    Connection connection;
    try{
        Class.forName(driverClass);
        connection=DriverManager.getConnection(url, user, password);
        Statement statement=connection.createStatement();
        String sql="delete from class where k = ?";
        PreparedStatement pst = connection.prepareStatement(sql);
        pst.setString(1,k);
        int row = pst.executeUpdate();
        if(row > 0){
            n = "删除数据成功";
        }else{
            n = "您删除的数据不存在，请重新选择";
        }
        request.setAttribute("n",n);
        pst.close();
        connection.close();
    }catch (Exception e){
        e.printStackTrace();
    }
%>
<head>
    <title>删除</title>
</head>
<body>
    <font size=2>
        ${n}
    </font><br>
    <a href="index.jsp" target="_self">
        <button>返回主页面</button>
    </a>
</body>
</html>

gaishu1.jsp中输入要修改的课程名称后提交给gaishu2.jsp输入要将该课程名称的其他内容修改为什么，进入后先判断数据库内是否有这个课程，如果有则继续输入，没有则提示没有

gaishu1.jsp：

<%@ page import="java.sql.*" %>
<%@ page import="java.nio.channels.Selector" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>修改界面</title>
</head>
<body>
<form action="gaishu2.jsp">
    <label for="k">课程:</label>
    <input type="text" id="k" name="k"><br>
    <input type="reset" value="重置">
    <input type="submit" value="提交">
</form>
</body>
</html>

gaishu2.jsp：

<%@ page import="java.sql.*" %>
<%@ page import="java.nio.channels.Selector" %>
<%@ page import="java.util.Properties" %>
<%@ page import="java.io.FileInputStream" %>
<%@ page import="java.util.Objects" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>修改生产计划</title>
</head>
<body>
<%
    String k = request.getParameter("k");
    session.setAttribute("k",k);
    String n = "修改的对象不存在";
    int z = 0;
    String driverClass="com.mysql.cj.jdbc.Driver";
    String url="jdbc:mysql://localhost:3306/test";
    String user="root";
    String password="zljzy962464";
    Connection connection;
    try{
        Class.forName(driverClass);
        connection=DriverManager.getConnection(url, user, password);
        Statement statement=connection.createStatement();
        String sql="select * from class";
        ResultSet rs=statement.executeQuery(sql);
        while(rs.next()){
            if(Objects.equals(rs.getString("k"), k)) {
                z++;
            }
        }
        if(z==0)
        {
            request.setAttribute("n",n);
%>
    <font size=2>
        ${n}
    </font>
    <a href="index.jsp" target="_self">
        <button>返回主页面</button>
    </a>
<%
}else{
%>
    <form action="gai.jsp">
        <label for="teacher">老师:</label>
        <input type="text" id="teacher" name="teacher"><br>
        <label for="address">教室:</label>
        <input type="text" id="address" name="address"><br>
        <input type="submit" value="提交">
    </form>
<%

        }
    }catch (Exception e){
        e.printStackTrace();
    }
%>
</body>
</html>

gai.jsp中连接数据库并完成修改的操作，数据库语言为

update后接表名，set后接要修改的表中的数据的列名，where后为判断条件，判断是否为要修改的课程

<%@ page import="java.sql.*" %>
<%@ page import="java.nio.channels.Selector" %>
<%@ page import="java.util.Arrays" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<%
    String n = "修改成功";
    request.setAttribute("n",n);
    String k = session.getAttribute("k").toString();
    String teacher=request.getParameter("teacher");
    String address=request.getParameter("address");
    String driverClass="com.mysql.cj.jdbc.Driver";
    String url="jdbc:mysql://localhost:3306/test";
    String user="root";
    String password="zljzy962464";
    Connection connection;
        try{
            Class.forName(driverClass);
            connection=DriverManager.getConnection(url, user, password);
            Statement statement=connection.createStatement();
            String sql="update class set teacher = ? ,address = ?where k = ?";
            PreparedStatement pst = connection.prepareStatement(sql);
            pst.setString(1,teacher);
            pst.setString(2,address);
            pst.setString(3,k);
            pst.executeUpdate();
            pst.close();
            connection.close();
        }catch (Exception e){
            e.printStackTrace();
        }

%>
<head>
    <title>修改界面</title>
</head>
<body>
    <font size=2>
        ${n}
    </font><br>
    <a href="index.jsp" target="_self">
        <button>返回主页面</button>
    </a>
</body>
</html>

chashu.jsp中输入要查询的老师，提交给cha.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<form action="cha.jsp">
    <label for="teacher">老师:</label>
    <input type="text" id="teacher" name="teacher"><br>
    <input type="reset" value="重置">
    <input type="submit" value="提交">
</form>
</body>
</html>

进入gai.jsp后连接数据库，查找的数据库语言为：

String sql="select * from class";

class为要查找的表名，from后接要查找的表名

<%@ page import="java.sql.*" %>
<%@ page import="java.nio.channels.Selector" %>
<%@ page import="java.util.Arrays" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<%
    String n = "修改成功";
    request.setAttribute("n",n);
    String k = session.getAttribute("k").toString();
    String teacher=request.getParameter("teacher");
    String address=request.getParameter("address");
    String driverClass="com.mysql.cj.jdbc.Driver";
    String url="jdbc:mysql://localhost:3306/test";
    String user="root";
    String password="zljzy962464";
    Connection connection;
        try{
            Class.forName(driverClass);
            connection=DriverManager.getConnection(url, user, password);
            Statement statement=connection.createStatement();
            String sql="update class set teacher = ? ,address = ?where k = ?";
            PreparedStatement pst = connection.prepareStatement(sql);
            pst.setString(1,teacher);
            pst.setString(2,address);
            pst.setString(3,k);
            pst.executeUpdate();
            pst.close();
            connection.close();
        }catch (Exception e){
            e.printStackTrace();
        }

%>
<head>
    <title>修改界面</title>
</head>
<body>
    <font size=2>
        ${n}
    </font><br>
    <a href="index.jsp" target="_self">
        <button>返回主页面</button>
    </a>
</body>
</html>

每个输入界面中的<label action=" ">中的href后的引号为要传入自己在该页面输入的内容到的那个页面，在那个页面中可以利用request.getParameter("")语句来接受上个页面传入的数据

try {
    Class.forName("com.mysql.cj.jdbc.Driver");
    String url = "jdbc:mysql://localhost:3306/test";
    String username = "root";
    String password = "zljzy962464";
    Connection connection = DriverManager.getConnection(url, username, password);
    Statement statement = connection.createStatement();
} catch (ClassNotFoundException e) {
    throw new RuntimeException(e);
}

以上的为连接数据库的基本步骤，之后根据自己不同的需求，定义String sql = " ";根据引号内不同的语句可以完成不同的操作。

pst.executeUpdate();

该语句为添加后对数据库内的内容更新，如果无该语句则添加的内容无法存入数据库中

标签：,String,request,connection,jsp,password,pst
From： https://www.cnblogs.com/zljzy/p/17875318.html

9

相关文章

赞助商

阅读排行