Servlet解析JSON数据和发送JSON数据

最新推荐文章于 2023-09-23 16:19:34 发布

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最新推荐文章于 2023-09-23 16:19:34 发布

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文章标签： servlet java json

本文介绍了一个基于Java的用户登录系统实现方法，通过JSON数据交换完成前后端交互，并使用Servlet处理登录请求。文章详细展示了如何从HTTP请求中读取JSON数据、验证用户登录信息以及返回相应的登录结果。

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[java] view plain copy

package com.jcuckoo.util;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import javax.servlet.http.HttpServletRequest;
import net.sf.json.JSONObject;

public class JsonReader {
    public static JSONObject receivePost(HttpServletRequest request) throws IOException, UnsupportedEncodingException {

        // 读取请求内容
        BufferedReader br = new BufferedReader(new InputStreamReader(request.getInputStream(),"utf-8"));
        String line = null;
        StringBuilder sb = new StringBuilder();
        while ((line = br.readLine()) != null) {
            sb.append(line);
        }
        //将json字符串转换为json对象
        JSONObject json=JSONObject.fromObject(sb.toString());
        return json;
    }
}

[java] view plain copy

package com.jcuckoo.servlet;

import java.io.IOException;
import java.io.Writer;
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 com.jcuckoo.pojos.User;
import com.jcuckoo.service.UserService;
import com.jcuckoo.util.JsonReader;
import net.sf.json.JSONObject;
@WebServlet("/LoginUserServlet")
public class LoginUserServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public LoginUserServlet() {
        super();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doPost(request, response);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // response.setContentType("text/html");
        // 设置字符编码为UTF-8, 这样支持汉字显示
        // response.setCharacterEncoding("UTF-8");

        response.setContentType("text/html;charset=utf-8");

        / 设置响应头允许ajax跨域访问 /
        response.setHeader("Access-Control-Allow-Origin", "");
        / 星号表示所有的异域请求都可以接受， /
        response.setHeader("Access-Control-Allow-Methods", "GET,POST");

        Writer out = response.getWriter();


        JSONObject json=JsonReader.receivePost(request);
        System.out.println(json);

        UserService userService=new UserService();

        //将建json对象转换为java对象
        User loginUser = (User)JSONObject.toBean(json,User.class);
        User user = userService.LoginUser(loginUser);
        JSONObject jsonObject=new JSONObject() ;
        if(user!=null){
            //将java对象转换为json对象
            jsonObject.put("user", JSONObject.fromObject(user));
            jsonObject.put("message", "用户登录成功！");
        }else{

            jsonObject.put("message", "用户登录失败！");
        }
        out.write(jsonObject.toString());
        out.flush();
    }
}

[java] view plain copy

<%@ page language="java" contentType="text/html; charset=utf-8"%>
<!DOCTYPE html >
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Servlet-jCuckoo</title>
<script type="text/javascript" src="js/jquery-3.1.1.min.js"></script>
</head>
<body>
    <form >
        用户名：<input type="text" id="userName"/><br/>
        密码：<input type="password" id="userPwd"/><br/>
        <input type="button" value="登录" id="sender">
    </form>
    <div id="messageDiv"></div>

    <script>
    $('#sender').click(function(){
        var userName=document.getElementById('userName').value;
        var userPwd=document.getElementById('userPwd').value;
        var user={userName:userName,userPwd:userPwd};
        var url="LoginUserServlet";

        $.post(url, JSON.stringify(user), function(data) {
              console.log(data);
             $("#messageDiv").html(data);
             var json=JSON.parse(data);
             alert(json.message);
         });
         / $.ajax({
            type:'post',
            url:url,
            dataType:"json",
            data:JSON.stringify(user),
            success: function (data) {
                var user=data.user;
                 $("#messageDiv").html(JSON.stringify(user));
                 alert(data.message);
            },
            error: function (data) {
                 alert(data.message);
                 $("#messageDiv").html("");
            }
        });  */

    });
    </script>
</body>
</html>

http://blog.youkuaiyun.com/guoquanyou/article/details/62421318

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