JavaWeb-Json的使用

1. 浏览器发送json数据到服务器：

（1）先将提交的数据封装成js对象。再使用JSON.stringfiy(对象名)转换为json对象，再通过ajax发送就好了;

	
	
	
	提交

POJO类：

package cn.ltp.bean;

public class User {
	private String username;
	private String password;
	private Integer age;
	
	public User() {
		super();
	}
	
	public User(String username, String password, Integer age) {
		super();
		this.username = username;
		this.password = password;
		this.age = age;
	}
	
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	
}

获取用户信息的servlet：

protected void doPost(HttpServletRequest request, HttpServletResponse response){
		try {
			request.setCharacterEncoding("utf-8");
		} catch (UnsupportedEncodingException e1) {
			e1.printStackTrace();
		}
		response.setContentType("text/html;charset=utf-8");
		
		String userInfo = null;
		try {
			userInfo = JsonUtils.jsonCastToString(request.getReader());
		} catch (IOException e1) {
			e1.printStackTrace();
		}
		
		 JSONObject jsonObject = JSONObject.fromObject(userInfo);
		 System.out.println(((User)jsonObject.toBean(jsonObject, User.class)).getUsername());
	
	}

fromObject方法是用来将json字符串转换为json对象。

toBean方法是用来将json对象转换成JavaBean对象

JSONArray.fromObject(list)方法用来将一个List转换成一个Json数组。

jsonArray.toString()将数组转换成String。

其中JSONObject的使用需要引入jar包。

JsonUtils工具类用于将读取到的字符流信息转换为字符串：

package cn.ltp.utils;

import java.io.BufferedReader;

public class JsonUtils {
	public static String jsonCastToString(BufferedReader reader){
		StringBuffer jb = new StringBuffer();
		 String line = null;
		 try {
		    while ((line = reader.readLine()) != null)
		      jb.append(line);
		 } catch (Exception e) {
			 e.printStackTrace();
			 return null;
		 }
		return jb.toString();
	}
}

服务器返回json数据给页面：

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("utf-8");
		response.setContentType("text/html;charset=utf-8");
		
		String jsonString = Service.getUser();
		request.setAttribute("userInfo_json", jsonString);
		request.getRequestDispatcher("/index.jsp").forward(request, response);
		//System.out.println(jsonString);
	}

页面接收json数据：

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









用户信息列表