Servlet@WebFilter注解方式——过滤器链的执行顺序

Servlet@WebFilter注解方式——过滤器链的执行顺序

执行顺序和类名字符排序有关！

以下是测试代码:

Filter0 .java

package Filter;

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.annotation.WebFilter;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
 * 过滤器链
 * @author xanwidtf@foxmail.com
 *
 */

@WebFilter(filterName="FirstFilter",urlPatterns="/index.jsp")
public class Filter0 implements Filter {

    @Override
    public void destroy() {
        System.out.println("FirstFilter过滤器destroy方法执行~");
    }

    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
            throws IOException, ServletException {
        System.out.println("Start……doFilter……FirstFilter");
        arg2.doFilter(arg0, arg1);
//       HttpServletRequest request = (HttpServletRequest) arg0;
//       HttpServletResponse response = (HttpServletResponse) arg1;
//       response.sendRedirect(request.getContextPath()+"/First.jsp");
        System.out.println("End……doFilter……FirstFilter");
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        System.out.println("过滤器init()执行了~");
    }

}

Filter1.java

package Filter;

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.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebFilter(filterName="SecondFilter",urlPatterns="/index.jsp")
public class Filter1 implements Filter {

    @Override
    public void destroy() {
        System.out.println("SecondFilter过滤器destroy方法执行~");
    }

    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
            throws IOException, ServletException {
        System.out.println("Start……doFilter……SecondFilter");
        arg2.doFilter(arg0, arg1);
//       HttpServletRequest request = (HttpServletRequest) arg0;
//       HttpServletResponse response = (HttpServletResponse) arg1;
//       response.sendRedirect(request.getContextPath()+"/Second.jsp");
        System.out.println("End……doFilter……SecondFilter");

    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        System.out.println("SecondFilter过滤器destroy方法执行~");

    }

}

输出：

Start……doFilter……FirstFilter
Start……doFilter……SecondFilter
处理过程执行了~
End……doFilter……SecondFilter
End……doFilter……FirstFilter

如果把Filter0改名为Filter2将会输出：

Start……doFilter……SecondFilter
Start……doFilter……FirstFilter
处理过程执行了~
End……doFilter……FirstFilter
End……doFilter……SecondFilter