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