spring boot 注册拦截器过程详解

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MyInterceptor implements HandlerInterceptor{
  @Override
  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    System.out.println("preHandler");
    return true;//这里一定要返回true要不然后面的不会执行
  }

  @Override
  public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    System.out.println("postHandler");
  }

  @Override
  public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
    System.out.println("afterHandler");
  }
}

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {

  @Override
  public void addInterceptors(InterceptorRegistry registry) {
    registry.addInterceptor(myInterceptor()).addPathPatterns("/**");//将自己的拦截器注册到spring中并添加拦截的路径
  }
  @Bean
  MyInterceptor myInterceptor(){
    return new MyInterceptor();//提供自己的拦截器的bean
  }
}

@RestController
public class HelloController {
  @GetMapping("gethello")
  public String getHello(){
    System.out.println("get hello");
    return "get hello";
  }
}