标签：web 拦截器 System Filter API org println import out

优先级按排序

1 过滤器(Filter)   最先进入拦截,只能获取到response,request 
2 拦截器(Interceptor) 可以获取到执行的类名,方法名
3 切片(Aspect) 可以获取到参数

具体使用哪一个看业务需求吧.

1 过滤器(Filter)

自定义Filter

package com.imooc.web.filter;
import org.springframework.stereotype.Component;
import java.io.IOException;
import java.util.Date;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
@Component  // 增加一个注解即可使用,不需要其他配置,会拦截所有请求
public class TimeFilter implements Filter {
	@Override
	public void destroy() {
		System.out.println("time filter destroy");
	}
	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {
		System.out.println("time filter start");
		long start = new Date().getTime();
		chain.doFilter(request, response); // 继续执行程序,不调用doFilter 不会往下执行
		System.out.println("time filter 耗时:"+ (new Date().getTime() - start));
		System.out.println("time filter finish");
	}
	@Override
	public void init(FilterConfig arg0) throws ServletException {
		// 程序启动会加载
		System.out.println("time filter init");
	}
}

　 如果是引用第三方的Filter 使用方法:

package com.imooc.web.config;
import java.util.ArrayList;
import java.util.List;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.imooc.web.filter.TimeFilter;
@Configuration
public class WebConfig {
	@Bean
	public FilterRegistrationBean timeFilter() {
		// 注册第三方Filter
		FilterRegistrationBean registrationBean = new FilterRegistrationBean();
		TimeFilter timeFilter = new TimeFilter();
		registrationBean.setFilter(timeFilter);
		// 需要拦截的url
		List<String> urls = new ArrayList<>();
		urls.add("/*");
		registrationBean.setUrlPatterns(urls);
		return registrationBean;
	}
}

2 拦截器(Interceptor)

　　2.1自定义Interceptor

package com.imooc.web.interceptor;
import java.util.Date;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

@Component
public class TimeInterceptor implements HandlerInterceptor {
	// 先进入该方法
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
			throws Exception {
		System.out.println("preHandle");
		System.out.println(((HandlerMethod)handler).getBean().getClass().getName());
		System.out.println(((HandlerMethod)handler).getMethod().getName());
		request.setAttribute("startTime", new Date().getTime());
		return true; // 返回true才能继续执行controller
	}
	// 如果Controller方法抛出了异常,不会进入该方法
	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
			ModelAndView modelAndView) throws Exception {
		System.out.println("postHandle");
		Long start = (Long) request.getAttribute("startTime");
		System.out.println("time interceptor 耗时:"+ (new Date().getTime() - start));

	}
	// 不管方法是不是抛出异常 都会进入该方法
	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
			throws Exception {
		System.out.println("afterCompletion");
		Long start = (Long) request.getAttribute("startTime");
		System.out.println("time interceptor 耗时:"+ (new Date().getTime() - start));
		System.out.println("ex is "+ex);

	}

}

　　　2.2 注入自定义的Interceptor

package com.imooc.web.config;

import com.imooc.web.interceptor.TimeInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
@Configuration
public class TimeInterceptorConfig extends WebMvcConfigurerAdapter {
    // 自定义的Interceptor
    @Autowired
    private TimeInterceptor timeInterceptor;

    // 注入spring
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(timeInterceptor);
    }

}

3 切片(Aspect)

自定义切片

package com.imooc.web.aspect;
import java.util.Date;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;
@Aspect
@Component
public class TimeAspect {
   // 切入具体的方法,拦截UserController的所有方法
   @Around("execution(* com.imooc.web.controller.UserController.*(..))")
   public Object handleControllerMethod(ProceedingJoinPoint pjp) throws Throwable {
      System.out.println("time aspect start");
      Object[] args = pjp.getArgs(); // 可以获取方法参数
      for (Object arg : args) {
         System.out.println("arg is "+arg);
      }
      long start = new Date().getTime();
      Object object = pjp.proceed(); // 继续往下执行Controller
      System.out.println("time aspect 耗时:"+ (new Date().getTime() - start));
      System.out.println("time aspect end");
      return object;
   }
}

标签：web,拦截器,System,Filter,API,org,println,import,out
来源： https://www.cnblogs.com/412013cl/p/14053607.html

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