axios进阶版

服务器发送JSON类型数据给客户端

如果将params：{}换成data：{}，则客户端发送的数据类型将变为JSON类型的数据

此时

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

将无法获取签到前端发送的JSON类型数据，需要使用字节流来接受JSON类型数据，将其转化为string类型数据。

//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
 

package com.atguigu.axios;

import com.atguigu.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);
    }
}

前端代码

    
    
    
    
    


    
        uname:

        pwd:

        
    

2.后端传输JSON数据给前端

1.注意一点，返回前端数据时，应声明为JSON格式 

 response.setContentType("application/json;charset=utf-8");

 2.后端发送的json数据，通过前端的value.data可以查出来，然后引用

package com.atguigu.axios;

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

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);
    }
}

前端代码

    
    
    
    
    


    
        uname:

        pwd: