Springmvc学习-Springmvc05-return_springmvc的return写法-优快云博客

本文链接：https://blog.youkuaiyun.com/Fu_si/article/details/104617842

本文介绍SpringMVC中如何使用Model、Map、ModelMap传递数据到视图，设置响应编码格式，并封装JSON对象返回给前端。探讨了直接在Controller拼装JSON字符串的方法。

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Springmvc05-return

1. 承载信息的对象

Model、Map<String, Object>、ModelMap

package com.caorui.handlers;

import java.util.Map;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;

//后端控制器
@Controller //该注解表示将当前类给spring容器管理
@Scope("prototype")
@RequestMapping("/springmvc")//该注解起了限定范围的作用
public class MyController {

	@RequestMapping("/hello")  //承载信息的对象
	public String hello(String username, int age, Model model, Map<String, Object> map, ModelMap modelMap ) { 
		System.out.println(username + " " + age);
		model.addAttribute("username", username);
		map.put("age", age);
		modelMap.addAttribute("gender", "female");
		return "welcome";
	}
	
}

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!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">
<title>Insert title here</title>
</head>
<body>
欢迎页面!+${username}+${age} + ${gender}
</body>
</html>

2. 设置响应编码格式、封装json对象返回给success

设置响应编码格式
@RequestMapping(value = “/hello”, produces = “text/html;charset=utf-8”) //响应编码格式
封装json对象返回给success(data)
@ResponseBody //放在方法上, 把返回的值封装成对象返回给success

package com.caorui.handlers;



import java.util.List;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;

import com.caorui.pojo.Star;

//后端控制器
@Controller //该注解表示将当前类给spring容器管理
@Scope("prototype")
@RequestMapping("/springmvc")//该注解起了限定范围的作用
public class MyController {
	@RequestMapping(value = "/hello", produces = "text/html;charset=utf-8") //响应编码格式 
	@ResponseBody //把返回的值封装成对象返回给success
	public String hello() { 
		return "china:瓷器";
	}
}

直接在controller里拼装json字符串，在页面用eval()方法转换成json对象

package com.caorui.handlers;



import java.io.IOException;


import javax.servlet.http.HttpServletResponse;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;


//后端控制器
@Controller //该注解表示将当前类给spring容器管理
@Scope("prototype")
@RequestMapping("/springmvc")//该注解起了限定范围的作用
public class MyController {
	@RequestMapping(value = "/hello", produces = "text/html;charset=utf-8") //响应编码格式 
	public void hello(HttpServletResponse response) throws IOException { 
		String json = "{\"name\":\"weilong\",\"flavor\":\"hot\"}";
		response.getWriter().println(json);
	}
}