认识达内从这里开始

拦截器

拦截器分同步拦截器和异步拦截器;

HandlerInterceptor

方法和执行时机

学JAVA成都可以看DispathcerServlet的原来确定它的三个方法的执行时机;

AsynHandlerInterceptor

看注释，主要用来清理在并发环境加清理ThreadLocal的数据;

ResponseBodyAdvice

对返回值备注了@ResponseBody或者返回ResponseEntity做了一些加工;

会在使用消息转换器转换为json数据之前进行数据转换输出;

package com.springbootpractice.interceptor.config;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.springbootpractice.interceptor.config.interceptor.MyInterceptor;

import lombok.SneakyThrows;

import org.springframework.context.annotation.Configuration;

import org.springframework.core.MethodParameter;

import org.springframework.http.HttpStatus;

import org.springframework.http.MediaType;

import org.springframework.http.ResponseEntity;

import org.springframework.http.server.ServerHttpRequest;

import org.springframework.http.server.ServerHttpResponse;

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

import org.springframework.web.servlet.HandlerInterceptor;

import org.springframework.web.servlet.config.annotation.InterceptorRegistry;

import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;

import java.util.HashMap;

import java.util.Map;

/**

* 说明：配置拦截器和设置统一返回格式

* @author carter

* 创建时间： 2020年02月19日 11:03 下午

**/

@Configuration

@ControllerAdvice

public class WebConfig implements WebMvcConfigurer, ResponseBodyAdvice {

@Override

public void addInterceptors(InterceptorRegistry registry) {

HandlerInterceptor myIntercepter = new MyInterceptor() ;

registry.addInterceptor(myIntercepter).addPathPatterns("/**");

}

@Override

public boolean supports(MethodParameter returnType, Class converterType) {

return true;

}

@SneakyThrows

@Override

public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {

Map map = new HashMap();

map.put("result","true");

map.put("data",body);

return new ObjectMapper().writeValueAsString(map);

}

}

小结

通过本小节，你可以学到：

学JAVA成都如何配置拦截器，打印每个http接口的耗时;

如何设置接口的统一返回格式;