业务场景:在web服务中添加日志,要求在刚进入方法和结束方法的时候打印开始和结束日志;进入方法好说,直接在第一行打印即可,但是return的时候可能会有很多分支,所以我们必须要在更上一层进行处理
实现步骤:
1.创建TestRequestBodyAdvice并实现RequestBodyAdvice接口,类上添加注解@ControllerAdvice
2.创建TestResponseBodyAdvice并实现ResponseBodyAdvice接口,类上添加注解@ControllerAdvice
3.修改其中的默认返回值;例如null改为对应值,false改为true(这个不要盲目的改)
4.引入logger类
5.在关键位置写入要打印的日志
具体代码如下:
@ControllerAdvice public class TestRequestBodyAdvice implements RequestBodyAdvice { private Logger logger= LoggerFactory.getLogger(TestRequestBodyAdvice.class); public boolean supports(MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) { return true; } public HttpInputMessage beforeBodyRead(HttpInputMessage httpInputMessage, MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) throws IOException { return httpInputMessage; } public Object afterBodyRead(Object object, HttpInputMessage httpInputMessage, MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) { logger.debug("即将进入{}方法",methodParameter.getMethod().getName()); return object; } public Object handleEmptyBody(Object object, HttpInputMessage httpInputMessage, MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) { return object; } } @ControllerAdvice public class TestResponseBodyAdvice implements ResponseBodyAdvice { private Logger logger= LoggerFactory.getLogger(TestResponseBodyAdvice.class); public boolean supports(MethodParameter methodParameter, Class aClass) { if (aClass.isAssignableFrom(MappingJackson2CborHttpMessageConverter.class)){ return true; } return false; } public Object beforeBodyWrite(Object object, MethodParameter methodParameter, MediaType mediaType, Class aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) { logger.debug("即将进入{}方法",methodParameter.getMethod().getName()); return object; } }
* 以上两个类并非只是打印日志的作用,他可以在所有请求的进入和返回时刻进行处理,例如进行简单的参数校验,或者查询为空时在此处理给前端一个默认返回值等 * 以上代码采用了适配器模式,通过supports函数来判断是否进入下面的函数进行逻辑处理