cat监控http请求-CatFilter

背景

CatFilter是用于http监控，即web项目里的controller类里的方法的监控。

实现原理其实就是servlet里的filter。

本文主要讲springboot web项目和非springboot web项目如何实现监控url监控。

CatFilter

是cat客户端jar里的类，实现了servlet里的Filter接口。

非springboot web项目

直接配置即可，配置filter之后，就相当于引入了过滤器，这个和servlet filter的使用方法一样。

---

web.xml

<!-- cat监控http请求-->
    <filter>
        <filter-name>cat-filter</filter-name>
        <filter-class>com.dianping.cat.servlet.CatFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>cat-filter</filter-name>
        <url-pattern>*.do</url-pattern>
    </filter-mapping>

springboob web项目

如果是拦截所有请求，就直接用cat自带的CatFilter即可。

但是如果要排除静态资源，就需要扩展CatFilter，因为springboot filter不支持排除资源路径，只支持pattern匹配。

扩展CatFilter

package com.xxx.qrcode.ugate.payment.filter;

import com.dianping.cat.servlet.CatFilter;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import org.springframework.util.AntPathMatcher;

/**
 * 重写CatFilter，排除.js/.css/.html等静态资源
 *
 * @author gzh
 * @createTime 2021/2/23 2:54 PM
 */
public class QrcodeCatFilter extends CatFilter {

  /**
   * 排除.js/.css/.html等静态资源
   */
  private static List<String> excludeUrlPatterns = Arrays.asList("/**/*.html", "/**/*.jsp",
      "/**/*.css", "/**/*.js", "/**/*.png", "/**/*.jpg",
      "/**/*.jpeg", "/**/*.gif", "/**/*.svg");

  private static AntPathMatcher antPathMatcher = new AntPathMatcher();

  @Override
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
      throws IOException,    ServletException {
    //获取当前请求的相对路径(即去掉域名/项目名字之后的路径)
    HttpServletRequest httpServletRequest = (HttpServletRequest)request;
    String ServletPath = httpServletRequest.getServletPath();

    //校验路径是否匹配
    boolean b = excludeUrlPatterns.stream()
        .anyMatch(e -> antPathMatcher.match(e, ServletPath));
    if (b) { //如果是静态资源，不走CatFilter
      chain.doFilter(request, response);
    }else { //如果不是静态资源，才走CatFilter
      super.doFilter(request, response, chain);
    }
  }
}

说明
1.自定义扩展类，覆盖了拦截方法doFilter，会根据是否是静态资源请求路径，来决定要不要被拦截。

2.启动的时候，CatFilter的init等方法，还是会被执行，因为自定义的扩展类继承了CatFilter。

配置过滤器

配置过滤器

/**
   * 配置过滤器
   * @return
   */
  @Bean
  public FilterRegistrationBean registerFilter() {
    FilterRegistrationBean registration = new FilterRegistrationBean();
    registration.setFilter(new QrcodeCatFilter());
//    registration.addUrlPatterns("*.do");
//    registration.addInitParameter("exclusions", "*.css");
//    registration.setName("CatFilter");
    return registration;
  }

---

完整配置

package com.xxx.xxx.ugate.payment.config.webconfig;

import com.xxx.qrcode.ugate.payment.filter.QrcodeCatFilter;
import com.xxx.qrcode.ugate.payment.intercepter.LogPreInterceptor;
import xxx.log.logback.web.LogbackConfigListener;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * LogbackConfigListener配置
 * 输出日志文件
 */
@Configuration
public class WebConfig implements WebMvcConfigurer {

  @Bean
  public ServletListenerRegistrationBean<LogbackConfigListener> initLogbackConfigListener() {
    ServletListenerRegistrationBean<LogbackConfigListener> result = new ServletListenerRegistrationBean<>();
    result.setListener(new LogbackConfigListener());
    return result;
  }

  /**
   * 配置拦截器
   * @param registry
   */
  @Override
  public void addInterceptors(InterceptorRegistry registry) {
    registry.addInterceptor(new LogPreInterceptor())
//        .addPathPatterns("/**/*.do")
        .excludePathPatterns("/**/*.html", "/**/*.jsp",
                                  "/**/*.css", "/**/*.js", "/**/*.png", "/**/*.jpg",
                                    "/**/*.jpeg", "/**/*.gif", "/**/*.svg");
  }

  /**
   * 配置过滤器
   * @return
   */
  @Bean
  public FilterRegistrationBean registerFilter() {
    FilterRegistrationBean registration = new FilterRegistrationBean();
    registration.setFilter(new QrcodeCatFilter());
//    registration.addUrlPatterns("*.do");
//    registration.addInitParameter("exclusions", "*.css");
//    registration.setName("CatFilter");
    return registration;
  }
}

参考

https://github.com/spring-pro...

jdk8知识点

如何排除静态资源请求路径？

自定义扩展过滤器的源码

package com.xxx.qrcode.ugate.payment.filter;

import com.dianping.cat.servlet.CatFilter;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import org.springframework.util.AntPathMatcher;

/**
 * 重写CatFilter，排除.js/.css/.html等静态资源
 *
 * @author gzh
 * @createTime 2021/2/23 2:54 PM
 */
public class QrcodeCatFilter extends CatFilter {

  /**
   * 排除.js/.css/.html等静态资源
   */
  private static List<String> excludeUrlPatterns = Arrays.asList("/**/*.html", "/**/*.jsp",
      "/**/*.css", "/**/*.js", "/**/*.png", "/**/*.jpg",
      "/**/*.jpeg", "/**/*.gif", "/**/*.svg");

  private static AntPathMatcher antPathMatcher = new AntPathMatcher();

  @Override
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
      throws IOException,    ServletException {
    //获取当前请求的相对路径(即去掉域名/项目名字之后的路径)
    HttpServletRequest httpServletRequest = (HttpServletRequest)request;
    String ServletPath = httpServletRequest.getServletPath();

    //校验路径是否匹配
    boolean b = excludeUrlPatterns.stream()
        .anyMatch(e -> antPathMatcher.match(e, ServletPath));
    if (b) { //如果是静态资源，不走CatFilter
      chain.doFilter(request, response);
    }else { //如果不是静态资源，才走CatFilter
      super.doFilter(request, response, chain);
    }
  }
}

排除静态资源的时候，用了jdk8的知识点。

1.得到流stream
主要是从集合得到流，这个是jdk8才有的功能和方法。

2.得到流之后，要对流数据进行计算
什么计算？匹配数据。怎么匹配？用anyMatch方法来匹配。

3.anyMatch方法的入参是Predicate类型
源码

public interface Stream<T> extends BaseStream<T, Stream<T>> {
/**
     * Returns whether any elements of this stream match the provided
     * predicate.  May not evaluate the predicate on all elements if not
     * necessary for determining the result.  If the stream is empty then
     * {@code false} is returned and the predicate is not evaluated.
     *
     * <p>This is a <a href="package-summary.html#StreamOps">short-circuiting
     * terminal operation</a>.
     *
     * @apiNote
     * This method evaluates the <em>existential quantification</em> of the
     * predicate over the elements of the stream (for some x P(x)).
     *
     * @param predicate a <a href="package-summary.html#NonInterference">non-interfering</a>,
     *                  <a href="package-summary.html#Statelessness">stateless</a>
     *                  predicate to apply to elements of this stream
     * @return {@code true} if any elements of the stream match the provided
     * predicate, otherwise {@code false}
     */
    boolean anyMatch(Predicate<? super T> predicate);

Predicate类型是函数式接口

/**
 * Represents a predicate (boolean-valued function) of one argument.
 *
 * <p>This is a <a href="package-summary.html">functional interface</a>
 * whose functional method is {@link #test(Object)}.
 *
 * @param <T> the type of the input to the predicate
 *
 * @since 1.8
 */
@FunctionalInterface //有函数式接口注解，说明就是函数式接口，即入参可以是lambda表达式语句或代码块
public interface Predicate<T> {

4.e是什么？
e是遍历流的时候，流里的当前元素。

5.AntPathMatcher
pattern模式匹配路径，spring框架自带的匹配路径功能。核心有两点：

1）*.do  
*，表示匹配0或多个字符  
2）/**  
/**，表示匹配0或多个目录

---

参考

jdk8实战

---

总结

除了用Jdk8里的知识点，去排除静态资源请求路径，当然也可以用传统的代码去排除。具体实现就是遍历集合数据，然后一个个数据去匹配当前请求路径。

参考：https://blog.csdn.net/qq_2393...