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Axios的快速学习

时间：2023-03-23 18:12:21浏览次数：46  
标签：Axios java String 学习 uname pwd str import 快速

资料来源于：B站尚硅谷JavaWeb教程(全新技术栈,全程实战) ，本人才疏学浅，记录笔记以供日后回顾
由于是多个视频内容混合在一起，因此只放了第一个链接
视频链接

知识点

Axios
   Axios是Ajax的一个框架,简化Ajax操作
   Axios执行Ajax操作的步骤：
   1. 添加并引入axios的js文件

   2-1. 客户端向服务器端异步发送普通参数值
    - 基本格式： axios().then().catch()
    - 示例：
      axios({
        method:"POST",
        url:"....",
        params:{
            uname:"lina",
            pwd:"ok"
        }
      })
      .then(function(value){})          //成功响应时执行的回调        value.data可以获取到服务器响应内容
      .catch(function(reason){});       //有异常时执行的回调          reason.response.data可以获取到响应的内容

                                                                   reason.message / reason.stack 可以查看错误的信息

    2-2. 客户端向服务器发送JSON格式的数据
    - 什么是JSON
      JSON是一种数据格式
      XML也是一种数据格式
      XML格式表示两个学员信息的代码如下：
      <students>
        <student sid="s001">
            <sname>jim</sname>
            <age>18</age>
        </student>
        <student sid="s002">
            <sname>tom</sname>
            <age>19</age>
        </student>
      </students>
      JSON格式表示两个学员信息的代码如下：
      [{sid:"s001",age:18},{sid:"s002",age:19}]
    - JSON表达数据更简洁，更能够节约网络带宽
    - 客户端发送JSON格式的数据给服务器端
    1) 客户端中params需要修改成：  data:
    2) 服务器获取参数值不再是 request.getParameter()...
       而是：
       StringBuffer stringBuffer = new StringBuffer("");
       BufferedReader bufferedReader = request.getReader();
       String str = null ;
       while((str=bufferedReader.readLine())!=null){
           stringBuffer.append(str);
       }
       str = stringBuffer.toString() ;

    3) 我们会发现 str的内容如下：
       {"uname":"lina","pwd":"ok"}

    -  服务器端给客户端响应JSON格式的字符串，然后客户端需要将字符串转化成js Object

Axios图示

代码示例

01.演示Axios发送普通的参数值给服务器端

demo09.html
点击查看代码 
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>01.演示Axios发送普通的参数值给服务器端</title>
    <script language="JavaScript" src="script/vue.js"></script>
    <script language="JavaScript" src="script/axios.min.js"></script>
    <script language="JavaScript">
        window.onload=function(){
            var vue = new Vue({
                "el":"#div0",
                data:{
                    uname:"lina",
                    pwd:"ok"
                },
                methods:{
                    axios01:function(){
                        axios({
                            method:"POST",
                            url:"axios01.do",
                            params:{
                                uname:vue.uname,
                                pwd:vue.pwd
                            }
                        })
                            .then(function (value) {
                                console.log(value);
                            })
                            .catch(function (reason) {
                                console.log(reason);
                            });
                    }
                }
            });
        }
    </script>
</head>
<body>
    <div id="div0">
        uname:<input type="text" v-model="uname"/><br/>
        pwd:<input type="text" v-model="pwd"/><br/>
        <input type="button" @click="axios01" value="发送一个带普通请求参数值的异步请求"/>
    </div>
</body>
</html>
Axios01Servlet.java
点击查看代码 
package com.ypf.axios;

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

@WebServlet("/axios01.do")
public class Axios01Servlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");

        String uname = request.getParameter("uname");
        String pwd = request.getParameter("pwd");

        System.out.println("uname = " + uname);
        System.out.println("pwd = " + pwd);

        response.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        out.write(uname+"_"+pwd);

        throw new NullPointerException("这里故意抛出一个空指针异常....");
    }
}

02.演示Axios发送JSON格式的参数值给服务器端

需要添加gson的jar包，此处使用的是gson-2.2.4.jar

demo10.html
点击查看代码 
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>02.演示Axios发送JSON格式的参数值给服务器端</title>
    <script language="JavaScript" src="script/vue.js"></script>
    <script language="JavaScript" src="script/axios.min.js"></script>
    <script language="JavaScript">
        window.onload=function(){
            var vue = new Vue({
                "el":"#div0",
                data:{
                    uname:"lina",
                    pwd:"ok"
                },
                methods:{
                    axios02:function(){
                        axios({
                            method:"POST",
                            url:"axios02.do",
                            data:{
                                uname:vue.uname,
                                pwd:vue.pwd
                            }
                        })
                            .then(function (value) {
                                console.log(value);
                            })
                            .catch(function (reason) {
                                console.log(reason);
                            });
                    }
                }
            });
        }
    </script>
</head>
<body>
    <div id="div0">
        uname:<input type="text" v-model="uname"/><br/>
        pwd:<input type="text" v-model="pwd"/><br/>
        <input type="button" @click="axios02" value="发送JSON格式的参数值的异步请求"/>
    </div>
</body>
</html>
Axios02Servlet.java
点击查看代码 
package com.ypf.axios;

import com.ypf.pojo.User;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

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

@WebServlet("/axios02.do")
public class Axios02Servlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        StringBuffer stringBuffer = new StringBuffer("");
        BufferedReader bufferedReader = request.getReader();
        String str = null ;
        while((str=bufferedReader.readLine())!=null){
            stringBuffer.append(str);
        }
        str = stringBuffer.toString() ;

        //已知 String
        //需要转化成 Java Object

        Gson gson = new Gson();
        //Gson有两个API
        //1.fromJson(string,T) 将字符串转化成java object
        //2.toJson(java Object) 将java object转化成json字符串，这样才能响应给客户端

        User user = gson.fromJson(str, User.class);

        System.out.println(user);
    }
}
User.java
点击查看代码 
package com.ypf.pojo;

public class User {
    private String uname ;
    private String pwd ;

    public User(){}

    public User(String uname, String pwd) {
        this.uname = uname;
        this.pwd = pwd;
    }

    public String getUname() {
        return uname;
    }

    public void setUname(String uname) {
        this.uname = uname;
    }

    public String getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

    @Override
    public String toString() {
        return "User{" +
                "uname='" + uname + '\'' +
                ", pwd='" + pwd + '\'' +
                '}';
    }
}

03.演示Axios发送异步请求给服务器端，服务器响应json格式的数据给客户端

demo11.html
点击查看代码 
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>03.演示Axios发送异步请求给服务器端，服务器响应json格式的数据给客户端</title>
    <script language="JavaScript" src="script/vue.js"></script>
    <script language="JavaScript" src="script/axios.min.js"></script>
    <script language="JavaScript">
        window.onload=function(){
            var vue = new Vue({
                "el":"#div0",
                data:{
                    uname:"lina",
                    pwd:"ok"
                },
                methods:{
                    axios03:function(){
                        axios({
                            method:"POST",
                            url:"axios03.do",
                            data:{
                                uname:vue.uname,
                                pwd:vue.pwd
                            }
                        })
                            .then(function (value) {
                                var data = value.data;
                                // data对应的数据：
                                // {uname:"鸠摩智",pwd:"ok"}
                                vue.uname=data.uname;
                                vue.pwd=data.pwd;

                                //此处value中的data返回的是 js object，因此可以直接点出属性
                                //如果我们获取的是一个字符串：  "{uname:\"鸠摩智\",pwd:\"ok\"}"

                                //js语言中 也有字符串和js对象之间互转的API
                                //string JSON.stringify(object)     object->string
                                //object JSON.parse(string)         string->object
                            })
                            .catch(function (reason) {
                                console.log(reason);
                            });
                    }
                }
            });
        }
    </script>
</head>
<body>
    <div id="div0">
        uname:<input type="text" v-model="uname"/><br/>
        pwd:<input type="text" v-model="pwd"/><br/>
        <input type="button" @click="axios03" value="服务器响应json格式的数据给客户端"/>
    </div>
</body>
</html>
Axios03Servlet.java
点击查看代码 
package com.ypf.axios;

import com.google.gson.Gson;
import com.ypf.pojo.User;

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

@WebServlet("/axios03.do")
public class Axios03Servlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        StringBuffer stringBuffer = new StringBuffer("");
        BufferedReader bufferedReader = request.getReader();
        String str = null ;
        while((str=bufferedReader.readLine())!=null){
            stringBuffer.append(str);
        }
        str = stringBuffer.toString() ;

        //已知 String
        //需要转化成 Java Object

        Gson gson = new Gson();
        //Gson有两个API
        //1.fromJson(string,T) 将字符串转化成java object
        //2.toJson(java Object) 将java object转化成json字符串，这样才能响应给客户端

        User user = gson.fromJson(str, User.class);
        user.setUname("鸠摩智");
        user.setPwd("123456");

        //假设user是从数据库查询出来的，现在需要将其转化成json格式的字符串，然后响应给客户端
        String userJsonStr = gson.toJson(user);
        response.setCharacterEncoding("UTF-8");
        //MIME-TYPE
        response.setContentType("application/json;charset=utf-8");
        response.getWriter().write(userJsonStr);
    }
}

04.JS中的字符串和Object之间互转的API

demo12.html
点击查看代码 
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>04.JS中的字符串和Object之间互转的API</title>
    <script language="JavaScript">
        function hello01(){
            /*
            //1. js string - > js object
            var str = "{\"uname\":\"lina\",\"age\":20}";
            var user = JSON.parse(str);
            alert(typeof user);
            alert(user.uname+"_"+user.age);
            */

            //2. js object -> js string
            var user = {"uname":"lina","age":99};
            alert(typeof user);
            var userStr = JSON.stringify(user);
            alert(typeof userStr);
            alert(userStr);
        }
    </script>
</head>
<body>
    <div id="div0">
        <input type="button" value="确定" onclick="hello01()"/>
    </div>
</body>
</html>

标签：Axios,java,String,学习,uname,pwd,str,import,快速
From： https://www.cnblogs.com/fgcs111/p/17248395.html

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