在java滤波器中计算响应时间

Question

我不知道java滤波器中doFilter（）方法的生命周期。 我想知道如果我要在方法开始的请求中设置一个开始时间，是否有方法或地方在方法中设置一个停止时间，该方法可以让我从请求开始时的总耗用时间到响应时间？ 我见过一个带有finally块的doFilter（）方法，我想知道在响应中设置停止时间是否合适？

Answer 1

import java.io.IOException; 
import javax.servlet.Filter; 
import javax.servlet.FilterChain; 
import javax.servlet.FilterConfig; 
import javax.servlet.ServletException; 
import javax.servlet.ServletRequest; 
import javax.servlet.ServletResponse; 
import javax.servlet.http.HttpServletRequest; 

public class ResponseTimerFilter implements Filter { 
    protected FilterConfig config; 

    public void init(FilterConfig config) throws ServletException { 
    this.config = config; 
    } 

    public void destroy() { 
    } 

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) 
     throws ServletException, IOException { 
    long startTime = System.currentTimeMillis(); 
    chain.doFilter(request, response); 
    long elapsed = System.currentTimeMillis() - startTime; 
    String name = "servlet"; 
    if (request instanceof HttpServletRequest) { 
     name = ((HttpServletRequest) request).getRequestURI(); 
    } 

    config.getServletContext().log(name + " took " + elapsed + " ms"); 
    } 
} 

web.xml 
<filter> 
    <filter-name>Timing Filter</filter-name> 
    <filter-class>com.omh.filters.ResponseTimerFilter</filter-class> 
</filter> 

<filter-mapping> 
    <filter-name>Timing Filter</filter-name> 
    <url-pattern>/*</url-pattern> 
</filter-mapping>