Filter 过滤程序过滤非法ip地址

「爱情、让人受尽委屈。」 2022-02-05 11:04 184阅读 0赞

登录界面

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
    <%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    %>
    
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
      <head>
        <base href="<%=basePath%>">
        
        <title>My JSP 'login_form.jsp' starting page</title>
        
    	<meta http-equiv="pragma" content="no-cache">
    	<meta http-equiv="cache-control" content="no-cache">
    	<meta http-equiv="expires" content="0">    
    	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    	<meta http-equiv="description" content="This is my page">
    	
    
      </head>
      
      <body>
      <pre>
      <form action="login_accept" method="post">
       用户名：<input type="text" name="name"/><br/>
       身  份：<input type="text" name="identity"/><br/>
              <input type="submit" value="提交"/><br/>  
     </form>
     </pre>
     ${errorip }
      </body>
    </html>

Servlet 处理程序

LoginAcceptServlet.java

package servlet;
    import java.io.IOException;
    import java.io.PrintWriter;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    public class LoginAcceptServlet extends HttpServlet {
    
    	public void doGet(HttpServletRequest request, HttpServletResponse response)
    			throws ServletException, IOException {
            String name=request.getParameter("name");
            String identity=request.getParameter("identity");
            PrintWriter out=response.getWriter();
            System.out.println(name+" "+identity);
            out.println(name+"<br/>");
            out.println(identity);
    	}
    	public void doPost(HttpServletRequest request, HttpServletResponse response)
    			throws ServletException, IOException {
    
    		 doGet(request,response);
    	}
    }

Filter 过滤程序

FilterTest1.java 过滤字符集

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;
    
    public class FilterTest1 implements Filter {
    
    	
        private String encoding=null;
    	public void destroy() {
    		// TODO Auto-generated method stub
    	}
    	public void doFilter(ServletRequest request, ServletResponse response,
    			FilterChain chain) throws IOException, ServletException {
    		request.setCharacterEncoding(encoding);
    		response.setCharacterEncoding(encoding);
    		
    		response.setContentType("text/html;charset=utf-8");
    	
    		chain.doFilter(request, response);
    	}
    	public void init(FilterConfig config) throws ServletException {
    		encoding=config.getInitParameter("characterencoding");
    	}
       
    }

FilterTest2.java 过滤非法ip

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;
    
    public class FilterTest2 implements Filter {
    
    	public void destroy() {}
    	public void doFilter(ServletRequest request, ServletResponse response,
    			FilterChain chain) throws IOException, ServletException {
    		String ip=request.getRemoteAddr();
    		System.out.println(ip+"  ");
    		if(ip.startsWith("127"))
    		{
    			System.out.println(ip+"  ");
    			chain.doFilter(request, response);
    		}
    		else
    		{
    			System.out.println("防止非法ip登陆");
    			request.setAttribute("errorip", "地址不正确，不能登录");
    			request.getRequestDispatcher("login_form.jsp").forward(request, response);
    		}
    	}
    	public void init(FilterConfig arg0) throws ServletException {}
    
    	
    
    }

配置文件 web.xml

<?xml version="1.0" encoding="UTF-8"?>
    <web-app version="2.5" 
    	xmlns="http://java.sun.com/xml/ns/javaee" 
    	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
    	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    	<filter>
      <filter-name>encodingFilter</filter-name>
      <filter-class>filter.FilterTest1</filter-class>
      <init-param>
       <param-name>characterencoding</param-name>
       <param-value>utf-8</param-value>
      </init-param>
     </filter>
     <filter>
      <filter-name>ipFilter</filter-name>
      <filter-class>filter.FilterTest2</filter-class>
     </filter>
     <filter-mapping>
      <filter-name>encodingFilter</filter-name>
      <url-pattern>/*</url-pattern>
     </filter-mapping>
      <filter-mapping>
      <filter-name>ipFilter</filter-name>
      <url-pattern>/*</url-pattern>
     </filter-mapping>
      <servlet>
        <description>This is the description of my J2EE component</description>
        <display-name>This is the display name of my J2EE component</display-name>
        <servlet-name>LoginAcceptServlet</servlet-name>
        <servlet-class>servlet.LoginAcceptServlet</servlet-class>
      </servlet>
    
      <servlet-mapping>
        <servlet-name>LoginAcceptServlet</servlet-name>
        <url-pattern>/login_accept</url-pattern>
      </servlet-mapping>
      <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
      </welcome-file-list>
    </web-app>