SpringBoot中的一些注解总结

1：@RestController

那么这个注解和@Controller有什么区别？

嗯哼，事情开始变得有意思起来了

1. Controller, RestController的共同点

     都是用来表示spring某个类的是否可以接收HTTP请求

2.  Controller, RestController的不同点

     @Controller标识一个Spring类是Spring MVC controller处理器

     @RestController： @RestController是@Controller和@ResponseBody的结合体，两个标注合并起来的作用。

下面是@RestController的源码，看了之后你会更清晰的看出来他们之间的区别

 * Copyright 2002-2016 the original author or authors.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;import org.springframework.stereotype.Controller;/** * A convenience annotation that is itself annotated with * {@link Controller @Controller} and {@link ResponseBody @ResponseBody}. * <p> * Types that carry this annotation are treated as controllers where * {@link RequestMapping @RequestMapping} methods assume * {@link ResponseBody @ResponseBody} semantics by default. * * <p><b>NOTE:</b> {@code @RestController} is processed if an appropriate * {@code HandlerMapping}-{@code HandlerAdapter} pair is configured such as the * {@code RequestMappingHandlerMapping}-{@code RequestMappingHandlerAdapter} * pair which are the default in the MVC Java config and the MVC namespace. * In particular {@code @RestController} is not supported with the * {@code DefaultAnnotationHandlerMapping}-{@code AnnotationMethodHandlerAdapter} * pair both of which are also deprecated. * * @author Rossen Stoyanchev * @author Sam Brannen * @since 4.0 */@Target(ElementType.TYPE)@Retention(RetentionPolicy.RUNTIME)@Documented@Controller@ResponseBodypublic @interface RestController {/** * The value may indicate a suggestion for a logical component name, * to be turned into a Spring bean in case of an autodetected component. * @return the suggested component name, if any * @since 4.0.1 */String value() default "";}

这里需要注意一点：当你在springboot中使用模板模式返回一个字符串去匹配对应的页面的时候，方法所在的类是不能使用@RestController而应该使用@Controller，为什么？看上面。当然，如果http请求是通过ajax发送到服务端，还是要使用@RestController注解的。