SpringBoot拦截器原理解析及使用方法

import java.io.IOException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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

private class AuthenticationInterceptor implements HandlerInterceptor {
	// 在请求处理之前进行调用（Controller方法调用之前）
  @Override
  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws IOException{
  	System.out.println(request.getRequestURL());
  	User user = (User)request.getSession().getAttribute("USER");
    if(user != null){
    	return true;
    }else {
    	System.out.println("no login...");
    	// request.getRequestDispatcher("/index.html").forward(request, response);
    	response.sendRedirect(request.getContextPath()+"login.html");
    	return false;
    }
    return false;
  }
  
  // 在请求处理之后视图被渲染之前进行调用（Controller方法调用之后）
  @Override
  public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {
    System.out.println("postHandle...");
  }

	// 在请求结束之后、也就是视图被渲染之后进行调用（主要是用于进行资源清理工作）
  @Override
  public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
    System.out.println("afterCompletion...");
  }
}

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class WebSecurityConfig implements WebMvcConfigurer{
  @Override
  public void addInterceptors(InterceptorRegistry registry){
    registry.addInterceptor(new AuthenticationInterceptor())
    		//所有路径都被拦截
    		.addPathPatterns("/**")
    		//添加不拦截的路径
    		.excludePathPatterns("/userLogin", "/css/**", "/images/**", "/js/**", "/login.html");
    registry.addInterceptor(new OtherInterceptor())
        .addPathPatterns("/**");
  }
}