jQueryrocket

springMVC的返回值有ModelAndView,String,void,Object类型。今天就来整理一下。

目录结构：

 依赖：

<!-- jackson -->
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.10.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.10.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-annotations -->
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-annotations</artifactId>
    <version>2.10.0</version>
</dependency>

老版本的Jackson使用的包名为org.codehaus.jackson，而新版本使用的是com.fasterxml.jackson。

Jackson主要包含了3个模块：

  • jackson-core
  • jackson-annotations
  • jackson-databind
    其中，jackson-annotations依赖于jackson-core，jackson-databind又依赖于jackson-annotations。

Jackson有三种方式处理Json：

    1. 使用底层的基于Stream的方式对Json的每一个小的组成部分进行控制
    2. 使用Tree Model，通过JsonNode处理单个Json节点
    3. 使用databind模块，直接对Java

      对象进行序列化和反序列化

关键代码：

ReturnValueController

package com.kaspar.controller;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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

@Controller
@RequestMapping(value="/returnValue")
public class ReturnValueController {

    @RequestMapping("/returnModelAndView")  //返回ModelAndView
    public ModelAndView doModelAndView(String name, String password, ModelAndView mav){
        mav.addObject("name", name);
        mav.addObject("password", password);
        mav.setViewName("/showReturn.jsp");
        return mav;
        
    }
    
    @RequestMapping("/returnString") //返回String类型, 可以通过HttpServletRequest 来传递参数
    public String doString(String sname, String spassword, HttpServletRequest request){
        request.setAttribute("sname", sname);
        request.setAttribute("spassword", spassword);
        return "/showReturn.jsp";
        
    }
    
    @RequestMapping("/returnVoid") //无返回值,通过ServletAPI完成参数传递和跳转
    public void doVoid(String vname, String vpassword, HttpServletRequest request, HttpServletResponse response) throws Exception{
        request.setAttribute("vname", vname);
        request.setAttribute("vpassword", vpassword);
        request.getRequestDispatcher("/showReturn.jsp").forward(request, response);
    }
    
    @RequestMapping("/returnObjectValue") //返回Object对象需要开启消息转换器HttpMessageConverter,<mvc:annotation-driven/>
    @ResponseBody
    public Object doObjectValue(){
        return 12.34;
        
    }
    
    @RequestMapping("/returnObjectString") //返回String
    @ResponseBody
    public Object doObjectString(){
        return "Hello SpringMVC";
        
    }
    
    @RequestMapping("/returnObjectList") //返回List
    @ResponseBody
    public Object doObjectList(){
        List<String> list = new ArrayList<String>();
        list.add("String1");
        list.add("String2");
        list.add("String3");
        return list;
        
    }
    
    @RequestMapping("/returnObjectMap") //返回Map
    @ResponseBody
    public Object doObjectMap(){
        Map<String, String> map = new HashMap<String, String>();
        map.put("mk1", "kv1");
        map.put("mk2", "kv2");
        map.put("mk3", "kv3");
        return map;
        
    }
    
}

　　Spring-mvc.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:mvc="http://www.springframework.org/schema/mvc"  
    xmlns:context="http://www.springframework.org/schema/context"  
    xsi:schemaLocation="  
        http://www.springframework.org/schema/mvc 
        http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd  
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-4.0.xsd  
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-4.0.xsd">
    
    <!-- 开启驱动器注解 -->
    <mvc:annotation-driven />
    
    <!-- 静态资源设置,因为需要加入js静态资源 -->
    <mvc:resources location="/js/" mapping="/js/**"/>
    
    <!-- 扫描注解 -->
    <context:component-scan base-package="com.kaspar.controller" />    
    
</beans>

　　测试页面returnValue.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core"%>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>
<%
	String path = request.getContextPath();
	String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
			+ path + "/";
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<base href="<%=basePath%>">

<title>ReturnValue</title>
<script type="text/javascript" src="js/jquery-1.9.0.min.js"></script>
<script type="text/javascript">
	$(function() {
		//获取value值得ajax
		$("#value").on("click", function() {
			alert("123");
			$.ajax({
				type : "get",
				url : "returnValue/returnObjectValue.do",
				success : function(data) {
					alert("data: " + data);
				}
			});
		});
		//获取String值得ajax
		$("#string").on("click", function() {
			alert("123");
			$.ajax({
				type : "get",
				url : "returnValue/returnObjectString.do",
				success : function(data) {
					alert("data: " + data);
				}
			});
		});
		//获取List值得ajax
		$("#list").on("click", function() {
			alert("123");
			$.ajax({
				type : "get",
				url : "returnValue/returnObjectList.do",
				success : function(data) {
					for (var i = 0; i < data.length; i++)
						alert("data: " + data[i]);
				}
			});
		});
		//获取Map值得ajax
		$("#map").on("click", function() {
			alert("123");
			$.ajax({
				type : "get",
				url : "returnValue/returnObjectMap.do",
				success : function(data) {
					for ( var key in data) {
						alert("key: " + key + " value: " + data[key]);
					}
				}
			});
		});
	});
</script>
</head>
<body>

	返回ModelAndView
	<form action="returnValue/returnModelAndView.do">
		name: <input type="text" name="name"><br /> password:<input
			type="text" name="name"><br /> <input type="submit"
			value="submit">
	</form>
	<hr>
	返回String类型
	<form action="returnValue/returnString.do">
		name: <input type="text" name="sname"><br /> password:<input
			type="text" name="spassword"><br /> <input type="submit"
			value="submit">
	</form>
	<hr>
	无返回值
	<form action="returnValue/returnVoid.do">
		name: <input type="text" name="vname"><br /> password:<input
			type="text" name="vname"><br /> <input type="submit"
			value="submit">
	</form>
	<hr>
	返回Object对象,类型为数值型
	<input id="value" type="button" value="AjaxgetValue">
	<hr>
	返回Object对象,类型为String
	<input id="string" type="button" value="AjaxgetString">
	<hr>
	返回Object对象,类型为List
	<input id="list" type="button" value="AjaxgetList">
	<hr>
	返回Object对象,类型为Map
	<input id="map" type="button" value="AjaxgetMap">

</body>
</html>

　　跳转后的页面showReturn.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>    
<%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<base href="<%=basePath %>">
<title>ShowReturn</title>
</head>
<body>
返回ModelAndView
<div>
    <h3><c:out value="${name }" /></h3>
    <h3><c:out value="${password }" /></h3>
</div>
<hr>
返回String类型
<div>
    <h3><c:out value="${sname }" /></h3>
    <h3><c:out value="${spassword }" /></h3>
</div>
<hr>
无返回值
<div>
    <h3><c:out value="${vname }" /></h3>
    <h3><c:out value="${vpassword }" /></h3>
</div>
</body>
</html>

　　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">
	<servlet>
		<servlet-name>springmvc</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		 <init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>classpath:config/Spring-mvc.xml</param-value>
		</init-param>
		<load-on-startup>0</load-on-startup> 
	</servlet>
	 <servlet-mapping>
	 	<servlet-name>springmvc</servlet-name>
	 	<url-pattern>*.do</url-pattern>
	 </servlet-mapping>
	 <!-- 解决中文乱码 -->
<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>
</web-app>

　　

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原文地址：https://www.cnblogs.com/kaspar/p/12915144.html