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spring mvc返回json字符串的方式

                        spring mvc返回json字符串的方式

方案一:使用@ResponseBody 注解返回响应体 直接将返回值序列化json

           优点:不需要自己再处理

步骤一:在spring-servlet.xml文件中配置如下代码

<?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:mvc="http://www.springframework.org/schema/mvc"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd ">
 
     <!--使用Annotation方式 完成映射  -->
     <!--让spring扫描包下所有的类,让标注spring注解的类生效  -->
     <context:component-scan base-package="cn.yxj.controller"/>
     <mvc:annotation-driven/>  
     <!--视图解析器  -->
     <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
     <property name="prefix" value="/WEB-INF/jsp/"></property>
     <property name="suffix" value=".jsp"></property>
     </bean>
</beans>

步骤二:在处理器方法中打上@ResponseBody  标签

@RequestMapping(value="http://www.mamicode.com/hello5.do")
    @ResponseBody
    public String hello(HttpServletResponse response) throws IOException{
        UserInfo u1=new UserInfo();
        u1.setAge(15);
        u1.setUname("你好");
        
        UserInfo u2=new UserInfo();
        u2.setAge(152);
        u2.setUname("你好2");
        Map<String,UserInfo> map=new HashMap<String, UserInfo>();
        map.put("001", u1);
        map.put("002", u2);
        String jsonString = JSON.toJSONString(map);
        return jsonString;
    }

步骤三:使用ajax进行获取数据

<%@ 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>
    
    <script type="text/javascript" src="js/jquery-1.8.3.js"></script>
    <script type="text/javascript">
      $(function(){
         $("#btn").click(function(){
             $.ajax({
               url:"<%=path%>/Five.do",
               success:function(data){ 
               //解析对象
               //alert(data.uname+"\n"+data.age);
               //解析map
               //alert(data.info.age+"\n"+data.info.uname);
               //解析list
               $.each(data,function(i,dom){
               alert(dom.uname+"\n"+dom.age);
               });
               }
             });
         });
      });
    </script>
  </head>
  
  <body>
    <input type="button" value="ajax" id="btn"/>
    
  </body>
</html>

方案二:处理器方法的返回值---Object

  由于返回Object数据,一般都是将数据转化为JSON对象后传递给浏览器页面的,而这个由Object转换为Json,是由Jackson工具完成的,所以要导入jar包,将Object数据转化为json数据,需要Http消息

  转换器 HttpMessageConverter完成。而转换器的开启,需要由<mvc:annotation-driven/> 来完成,当spring容器进行初始化过程中,在<mvc:annotation-driven/> 处创建注解驱动时,默认创

  建了七个HttpMessageConverter对象,也就是说,我们注册<mvc:annotation-driven/>,就是为了让容器帮我们创建HttpMessageConverter对象

技术分享

 

详细代码看

方案二、使用返回字符串的处理器方法,去掉@ResponseBody注解

步骤一、同上

步骤二

@RequestMapping(value="http://www.mamicode.com/hello5.do")
    public String hello(HttpServletResponse response) throws IOException{
        UserInfo u1=new UserInfo();
        u1.setAge(15);
        u1.setUname("你好");
        
        UserInfo u2=new UserInfo();
        u2.setAge(152);
        u2.setUname("你好2");
        Map<String,UserInfo> map=new HashMap<String, UserInfo>();
        map.put("001", u1);
        map.put("002", u2);
        String jsonString = JSON.toJSONString(map);
        return jsonString;
    }

步骤三、在前台取值的时候需要我么做一遍处理

<%@ 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>
    
    <script type="text/javascript" src="js/jquery-1.8.3.js"></script>
    <script type="text/javascript">
      $(function(){
         $("#btn").click(function(){
             $.ajax({
               url:"<%=path%>/hello5.do",
               success:function(data){ //data指的是从server打印到浏览器的数据
                   //jsonString jsonObject
                   //{"001":{"age":122,"name":"顺利就业"}}
                  var result= eval("("+data+")");
                   $.each(result,function(i,dom){
                      alert(dom.age+"\n"+dom.uname);
                      
                   });
                //  alert(result["001"]["age"]);
               }
             });
         });
      });
    </script>
  </head>
  
  <body>
    <input type="button" value="ajax" id="btn"/>
    
  </body>
</html>

方案三:使用无返回值的处理器方法

步骤一:同上

步骤二:使用响应流回送数据

@RequestMapping(value="http://www.mamicode.com/hello5.do")
    public void hello(HttpServletResponse response) throws IOException{
        UserInfo u1=new UserInfo();
        u1.setAge(15);
        u1.setUname("你好");
        
        UserInfo u2=new UserInfo();
        u2.setAge(152);
        u2.setUname("你好2");
        Map<String,UserInfo> map=new HashMap<String, UserInfo>();
        map.put("001", u1);
        map.put("002", u2);
        String jsonString = JSON.toJSONString(map);
        response.setCharacterEncoding("utf-8");
        response.getWriter().write(jsonString);
        response.getWriter().close();
        
    }

步骤三:在前台取值也需要做处理

<%@ 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="http://www.mamicode.com/">
    
    <title>My JSP ‘index.jsp‘ starting page</title>
    
    <script type="text/javascript" src="http://www.mamicode.com/js/jquery-1.8.3.js"></script>
    <script type="text/javascript">
      $(function(){
         $("#btn").click(function(){
             $.ajax({
               url:"<%=path%>/hello5.do",
               success:function(data){ //data指的是从server打印到浏览器的数据
                   //jsonString jsonObject
                   //{"001":{"age":122,"name":"顺利就业"}}
                  var result= eval("("+data+")");
                   $.each(result,function(i,dom){
                      alert(dom.age+"\n"+dom.uname);
                      
                   });
                //  alert(result["001"]["age"]);
               }
             });
         });
      });
    </script>
  </head>
  
  <body>
    <input type="button" value="http://www.mamicode.com/ajax" id="btn"/>
    
  </body>
</html>

 

spring mvc返回json字符串的方式