SpringMVC -- 梗概--源码--壹--springMVC json处理

附：实体类

Class ： User

package com.c61.entity;

import java.text.SimpleDateFormat;
import java.util.Date;

import org.springframework.format.annotation.DateTimeFormat;

import com.alibaba.fastjson.annotation.JSONField;

public class User {
    private Integer id;
    private String name;
    //@DateTimeFormat(pattern="yyyy-MM-dd HH:mm:ss")
    @DateTimeFormat(pattern="yyyy-MM-dd")//定制在接收请求参数时的日期格式
    @JSONField(format="yyyy-MM-dd")//作用在java序列化成json时
    private Date birth;
    private String dateStr;
    
    public String getDateStr() {
        return dateStr;
    }
    public void setDateStr(String dateStr) {
        this.dateStr = dateStr;
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Date getBirth() {
        return birth;
    }
    public void setBirth(Date birth) {
        this.birth = birth;
        SimpleDateFormat format=new SimpleDateFormat("yyyy-MM-dd");
        this.dateStr=format.format(birth);
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", name=" + name + ", birth=" + birth + "]";
    }
    public User(){}
    public User(Integer id, String name, Date birth) {
        super();
        this.id = id;
        this.name = name;
        this.birth = birth;
    }
    
}

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

1.配置web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
    xmlns="http://java.sun.com/xml/ns/javaee" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <display-name></display-name>    
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  
  <!-- 前端控制器 
         /=默认的url-pattern
         /a/b/c  /a
         
         /a/d/c
         /a/d
         /a
         /
         *注意：此控制器默认加载/WEB-INF下的xxx-servlet.xml文件
                        ：其中xxx等于【DispatcherServlet的配置名】
  -->
  <servlet>
      <servlet-name>mvc61</servlet-name>
      <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
      <init-param>
          <param-name>contextConfigLocation</param-name>
          <param-value>classpath:mvc62.xml</param-value>
      </init-param>
      <!-- 随项目启动而启动 -->
      <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
      <servlet-name>mvc61</servlet-name>
      <url-pattern>/</url-pattern>
  </servlet-mapping>
  
  <!-- 专治Post请求参数乱码 -->
  <filter>
      <filter-name>encoding61</filter-name>
      <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
      <!-- 将请求的编码方式设置为utf-8 -->
      <init-param>
          <param-name>encoding</param-name>
          <param-value>utf-8</param-value>
      </init-param>
  </filter>
  <filter-mapping>
      <filter-name>encoding61</filter-name>
      <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>

2.配置SpringMVC.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- xmlns:xml name space 是每一个schema唯一标识 -->
<beans xmlns="http://www.springframework.org/schema/beans" 
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc" 
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                              http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
                              http://www.springframework.org/schema/context
                              http://www.springframework.org/schema/context/spring-context-3.2.xsd
                              http://www.springframework.org/schema/mvc
                              http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">

    <!-- 扫描所有控制器中的注解 -->
    <context:component-scan base-package="com.c61.controller"></context:component-scan>
    <!-- 
        MVC中基于注解开发，导入注解驱动
     -->
    <mvc:annotation-driven></mvc:annotation-driven>
</beans>

3.配置控制器

package com.c61.controller;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

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 com.c61.entity.User;

@Controller
@RequestMapping(value="/mvc5")//等价于namespace
public class JSONController {
    /**
     * 响应json
     * @return
     */
    @RequestMapping("/json")//等价于<action name="mvc1"
    @ResponseBody//可以加载方法上或者返回值上
                 //方法的返回值即请求的响应内容
                 //会将方法的返回值转换成json，并响应
    public User queryUser(){
        User user=new User(1,"lime",new Date());
        return user;
    }

    @RequestMapping("/jsons")//等价于<action name="mvc1"
    @ResponseBody//可以加载方法上或者返回值上
                 //方法的返回值即请求的响应内容
                 //会将方法的返回值转换成json，并响应
    public List<User> queryUsers(){
        User user1=new User(1,"lime1",new Date());
        User user2=new User(1,"lime2",new Date());
        User user3=new User(1,"lime3",new Date());
        List<User> users=new ArrayList<User>();
        users.add(user1);
        users.add(user2);
        users.add(user3);
        return users;
    }
    
    @RequestMapping("/json2")//等价于<action name="mvc1"
    @ResponseBody
    //@RequestBody：将请求体中的数据取出,解析成java对象,赋值给对应参数
    public String testJson(@RequestBody User user){
        System.out.println(user);
        return "ok";
    }
}

4.配置视图

View : json.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'index.jsp' starting page</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
    <script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-1.8.3.min.js"></script>
    <script type="text/javascript">
        $(function(){
            $("#json2").click(function(){
                $.ajax({
                    url:"${pageContext.request.contextPath}/mvc5/json2",
                    type:"post",
                    data:'{"id":1,"name":"limeOracle3","birth":"2016-09-29"}',
                    contentType:"application/json",//请求数据类型为json
                    success:function(ret){
                        alert(ret);
                    }
                });
            });
            $("#json").click(function(){
                $.ajax({
                    url:"${pageContext.request.contextPath}/mvc5/json",
                    type:"post",
                    success:function(ret){//由于springMVC在响应json时会设置响应头：application/json,
                                          //则ret已经时解析后的js对象
                        alert(ret.id+" "+ret.name+" "+ret.birth);
                    }
                });
            });
        });
    </script>
  </head>
  
  <body>
    <a href="${pageContext.request.contextPath}/mvc5/jsons">json</a>
    <input type="button" value="ajax_send_json" id="json2"/>
    <input type="button" value="ajax_receive_json" id="json"/>
  </body> 
</html>

Client ： 

Client ： json

Client ： ajax_send_json

Client ： ajax_receive_json

啦啦啦

啦啦啦

 

6.1 springMVC向客户端响应一个json ： @ResponseBody

6.1.1 使用方式

@ResponseBody//可以加在方法上或者返回值上
             //方法的返回值即请求的响应内容
             //会将方法的返回值转换成json，并响应
public User queryUser(){
    User user=new User(1,"lime",new Date());
    return user;
}
*注意：在springMVC将java对象序列化成json时，默认使用的是Jackson
     ：如果就是要使用jackson做序列化，只要导入jackson的jar包即可

6.1.2 springMVC响应json细节

springMVC在响应json时会设置响应头为:application/json,
响应头可以告知客户端响应数据的格式为json
所以在异步请求中，不用在定制【dataType:"json"】
    $.ajax({
        url:"${pageContext.request.contextPath}/mvc5/json",
        type:"post",
        success:function(ret){//由于springMVC在响应json时会设置响应头：application/json,
                              //则【$.ajax】会解析响应值，则ret已经是解析后的js对象
            alert(ret.id+" "+ret.name+" "+ret.birth);
        }
    });

6.2 springMVC接收客户端发送来的json数据：@RequestBody

$.ajax({
    url:"${pageContext.request.contextPath}/mvc5/json2",
    type:"post",
    data:'{"id":1,"name":"limeOracle3","birth":"2016-09-29"}',
    contentType:"application/json",//请求数据类型为json
    success:function(ret){
        alert(ret);
    }
});
//@RequestBody：将请求体中的数据取出,解析成java对象,赋值给对应参数
public String testJson(@RequestBody User user){
    System.out.println(user);
    return "ok";
}
*注意，@RequestBody需要jdk7，需要更换tomcat的jdk

6.3 springMVC更换JSON处理方案：由jackson换成fastjson

1>导入fastjson的jar
2>配置：
    <mvc:annotation-driven>
        <mvc:message-converters>
            <bean class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">
                <property name="supportedMediaTypes">
                    <list>
                        <!-- 支持的格式：application/json -->
                        <value>application/json</value>
                    </list>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>
3>如此则springMVC中使用@ResponseBody 和 @RequestBody时，需要做的json序列化和反序列化都由fastjson完成。

啦啦啦