JSON数据交互是最近火起来的，相比于xml，json更快速，通用。这里就用一个入门案例来学习一下json如何进行数据交互的。

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/javaee"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
	id="WebApp_ID" version="3.0">
	<!-- 项目名称 -->
	<display-name>JSONTest</display-name>
	
	<!-- 项目欢迎页，优先级按顺序降低 -->
	<welcome-file-list>
		<welcome-file>index.jsp</welcome-file>
	</welcome-file-list>
	
	<!-- 配置编码过滤器 -->
	<filter>
		<filter-name>CharacterEncodingFilter</filter-name>
		<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
		<init-param>
			<param-name>encoding</param-name>
			<param-value>UTF-8</param-value>
		</init-param>
	</filter>
	<filter-mapping>
		<filter-name>CharacterEncodingFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>

	<!-- 前端控制器 -->
	<servlet>
		<servlet-name>springmvc</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<!-- 初始化时加载配置文件 -->
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>classpath:springmvc-config.xml</param-value>
		</init-param>
		<!-- 1表示容器启动时立即加载servlet -->
		<load-on-startup>1</load-on-startup>
	</servlet>
	<servlet-mapping>
		<servlet-name>springmvc</servlet-name>
		<url-pattern>/</url-pattern>
	</servlet-mapping>
</web-app>

springmvc-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:p="http://www.springframework.org/schema/p"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xmlns:task="http://www.springframework.org/schema/task"
	xsi:schemaLocation="
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-4.3.xsd 
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-4.3.xsd 
        http://www.springframework.org/schema/mvc 
        http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd 
        http://www.springframework.org/schema/task 
        http://www.springframework.org/schema/task/spring-task-4.3.xsd">

	<!-- 使用包扫描 -->
	<context:component-scan
		base-package="ltd.ourfamily.controller"></context:component-scan>
	
	<!-- 配置注解驱动 -->
	<mvc:annotation-driven/>
	
	<!-- 配置静态资源，不会被拦截 -->
	<mvc:resources location="/js/" mapping="/js/**"/>
	
	<!-- 视图解析器 -->
	<bean id="viewResolver"
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<!-- 设置前缀 -->
		<property name="prefix" value="/WEB-INF/jsp/"></property>
		<!-- 设置后缀 -->
		<property name="suffix" value=".jsp"></property>
	</bean>
</beans>

index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>JSON数据交互</title>
<script type="text/javascript" src="${pageContext.request.contextPath }/js/jquery-1.11.1.min.js">
</script>
<script type="text/javascript">
function testJson() {
	var username=$("#username").val();
	var password=$("#password").val();
	var id=$("#id").val();
	$.ajax({
		url:"${pageContext.request.contextPath}/testJson",
		type:"post",
		data:JSON.stringify({id:id,username:username,password:password}),
		contentType:"application/json;charset=UTF-8",
		dataType:"json",
		success:function(data){
			if(data!=null){
				alert("用户名为："+data.username+",密码为："+data.password);
			}
		}
	});
}
</script>
</head>
<body>
	<form>
		id:<input type="number" name="id" id="id"><br>
		用户名：<input type="text" name="username" id="username"><br>
		密码：<input type="password" name="password" id="password"><br>
		<input type="button" value="点我测试" onclick="testJson()">
	</form>
</body>
</html>

UserController.java:

package ltd.ourfamily.controller;

import java.util.Date;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import ltd.ourfamily.po.Orders;
import ltd.ourfamily.po.User;
@Controller
public class UserController{
/**
 * 接受JSON数据，返回JSON格式的结果
 * @param orders
 * @return
 * @throws Exception
 */
	@RequestMapping(value="/testJson")
	@ResponseBody
	public User handleRequest(@RequestBody User user) throws Exception {
		System.out.println(user);
		return user;
	}

}

可以看出，json交互这里用到了ajax异步请求，使用注解@ResponseBody和@RequestBody获取到JSON类型的数据，并自动映射到User对象中。从而完成了JSON的数据交互。

2. RESTful支持

这里直接上案例吧，感觉restful风格和JSON有些相似，只是用了不同的注解。

在UserController类中新添selectUser方法：

然后新添一个restful.jsp页面用于根据编号来查询用户名：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="${pageContext.request.contextPath }/js/jquery-1.11.1.min.js">
</script>
<script type="text/javascript">
function search() {
	var id=$("#number").val();
	$.ajax({
		url:"${pageContext.request.contextPath}/user/"+id,
		type:"get",
		dataType:"json",
		success:function(data){
			if(data.username!=null){
				alert("用户名为："+data.username);
			}else{
				alert("您的输入有误");
			}
		}
	});
}
</script>
</head>
<body>
<form>
	编号：<input type="text" name="number" id="number"/>
	<input type="button" value="搜索" onclick="search()"/>
</form>
</body>
</html>

可以发现，restful风格采用了注解@PathVariable来绑定形参，而JSON则选用@RequestBody来绑定形参。相比于这两种，可以看出restful风格更加简便，但是可读性比较差，在restful的URL中，只传了参数值而没有传递参数名！

原文链接：https://blog.csdn.net/qq_37820491/article/details/89682923