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="/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
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="/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="/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="<%=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>