Explication détaillée d'exemples d'intercepteurs en Java

package com.example.interceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
public class IndexInterceptor implements HandlerInterceptor{
  @Override
  public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
      throws Exception {
    System.out.println(">>>IndexInterceptor>>>>>>>在整个请求结束之后被调用，也就是在DispatcherServlet 渲染了对应的视图之后执行（主要是用于进行资源清理工作）");
  }
  @Override
  public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
      throws Exception {
    System.out.println(">>>IndexInterceptor>>>>>>>请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后）");
  }
  @Override
  public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2) throws Exception {
     System.out.println(">>>IndexInterceptor>>>>>>>在请求处理之前进行调用（Controller方法调用之前）");
     // 只有返回true才会继续向下执行，返回false取消当前请求
     return true;
  }
}

package com.example.interceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
public class IndexInterceptor2 implements HandlerInterceptor{
  @Override
  public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
      throws Exception {
    System.out.println(">>>IndexInterceptor2>>>>>>>在整个请求结束之后被调用，也就是在DispatcherServlet 渲染了对应的视图之后执行（主要是用于进行资源清理工作）");
  }
  @Override
  public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
      throws Exception {
    System.out.println(">>>IndexInterceptor2>>>>>>>请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后）");
  }
  @Override
  public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2) throws Exception {
     System.out.println(">>>IndexInterceptor2>>>>>>>在请求处理之前进行调用（Controller方法调用之前）");
     // 只有返回true才会继续向下执行，返回false取消当前请求
     return false;
  }
}

package com.example.config;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import com.example.interceptor.IndexInterceptor;
import com.example.interceptor.IndexInterceptor2;
//只要能被springboot扫描到即可
@Configuration
public class SimpleWebAppConfigurer extends WebMvcConfigurerAdapter{
  @Override
  public void addInterceptors(InterceptorRegistry registry) {
    // 多个拦截器组成一个拦截器链
    // addPathPatterns 用于添加拦截规则
    // excludePathPatterns 用户排除拦截
    registry.addInterceptor(new IndexInterceptor()).addPathPatterns("/**");
    registry.addInterceptor(new IndexInterceptor2()).addPathPatterns("/**");
    super.addInterceptors(registry);
  }
}