Spring编程：@ResponseBody 注解

Posted 2022-06-07 志波同学

1.定义

@ResponseBody 注解是一个标识型注解，无需设置任何参数值。该注解的作用是：将 Controller 方法返回的对象，转换为 JSON 格式，通过 response 对象返回给客户端。

2.源代码

package org.springframework.web.bind.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Annotation that indicates a method return value should be bound to the web
 * response body. Supported for annotated handler methods in Servlet environments.
 *
 * <p>As of version 4.0 this annotation can also be added on the type level in
 * which case it is inherited and does not need to be added on the method level.
 *
 * @author Arjen Poutsma
 * @since 3.0
 * @see RequestBody
 * @see RestController
 */
@Target(ElementType.TYPE, ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ResponseBody 

该注解指示方法的返回值应该被绑定到 web 响应体中。仅在 servlet 环境中可注解的方法上使用。从 4.0 开始，该注解可以被添加的类级别上，该类中的方法会继承类上的注解，无需单独的为类中方法添加注解。

3.代码示例

产品 Controller 类

package org.learn.controller;

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


@Controller
@RequestMapping("/product")
public class ProductController 

    @ResponseBody
    @RequestMapping("/detail")
    public ProductDO getUser()
        ProductDO productDO = new ProductDO();
        productDO.setName("华为手机Mate20");
        productDO.setDescription("华为手机");
        return productDO;
    

产品类：

package org.learn.controller;

import java.io.Serializable;

/**
 * 产品类
 *
 * @author zhibo
 * @date 2019-07-25 10:39
 */
public class ProductDO implements Serializable 
    private static final long serialVersionUID = 6550342067524547999L;
    private String name;
    private String description;

    public String getName() 
        return name;
    
    public void setName(String name) 
        this.name = name;
    
    public String getDescription() 
        return description;
    
    public void setDescription(String description) 
        this.description = description;
    

运行代码，执行结果如下图所示：

4.@RestController注解

@RestController 注解作用于类上，等于 @Controller 与 @ResponseBody 同时作用于类。

@RestController
@RequestMapping("/product")
public class ProductController 
    @RequestMapping("/detail")
    public ProductDO getUser()
        ProductDO productDO = new ProductDO();
        productDO.setName("华为手机Mate20");
        productDO.setDescription("华为手机");
        return productDO;
    

等同于

@Controller
@ResponseBody
@RequestMapping("/product")
public class ProductController 
    @RequestMapping("/detail")
    public ProductDO getUser()
        ProductDO productDO = new ProductDO();
        productDO.setName("华为手机Mate20");
        productDO.setDescription("华为手机");
        return productDO;
    

本文内容适合于初学 springmvc 的同学。文章内容仅代表个人观点，如有不正之处，欢迎批评指正，谢谢大家。