JavaWeb过滤器详解

<%@ page language="java" import="java.util.*" cOntentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>



 
  
  
  
  
  
  
    
  
  
  

 
 
 
 /servlet/LoginServlet" method="post" >
  用户名:
 密码:
 
 
 

<%@ page language="java" import="java.util.*" pageEncoding="utf-8" cOntentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>



 
  
  
  
  
  
    
  
  
  
 
 
 
  
 

<%@ page language="java" import="java.util.*" cOntentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>



 
  
  
  
  
  
  
    
  
  
  

 
 
 
 登录失败，请检查用户名或密码！
 

package com.cityhuntshou.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.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class LoginFilter implements Filter {
  private FilterConfig config;
  public void destroy() {
    

  }

  public void doFilter(ServletRequest arg0, ServletResponse arg1,
      FilterChain arg2) throws IOException, ServletException {
    HttpServletRequest request = (HttpServletRequest) arg0;
    HttpServletResponse respOnse= (HttpServletResponse) arg1;
    HttpSession session = request.getSession();
    
    
    //过滤器实际应用场景之二-----编码转换
    
    String charset = config.getInitParameter("charset");
    
    if(charset == null)
    {
      charset = "UTF-8";
    }
    
    request.setCharacterEncoding(charset);
    
    String noLoginPaths = config.getInitParameter("noLoginPaths");
    
    
    
    if(noLoginPaths != null)
    {
    String[] strArray = noLoginPaths.split(";");
    for(int i = 0; i 

package com.cityhuntshou.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;
import javax.servlet.http.HttpSession;

public class LoginServlet extends HttpServlet {

  /**
   * Constructor of the object.
   */
  public LoginServlet() {
    super();
  }

  /**
   * Destruction of the servlet. 

   */
  public void destroy() {
    super.destroy(); // Just puts "destroy" string in log
    // Put your code here
  }

  /**
   * The doGet method of the servlet. 

   *
   * This method is called when a form has its tag value method equals to get.
   * 
   * @param request the request send by the client to the server
   * @param response the response send by the server to the client
   * @throws ServletException if an error occurred
   * @throws IOException if an error occurred
   */
  public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {

    
  }

  /**
   * The doPost method of the servlet. 

   *
   * This method is called when a form has its tag value method equals to post.
   * 
   * @param request the request send by the client to the server
   * @param response the response send by the server to the client
   * @throws ServletException if an error occurred
   * @throws IOException if an error occurred
   */
  public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {

    String username = request.getParameter("username");
    String password = request.getParameter("password");
    //new String(username.getBytes("ISO-8859-1"),"UTF-8")
    System.out.println(username);
    if("admin".equals(username) && "admin".equals(password))
    {
      //校验通过
      HttpSession session = request.getSession();
      session.setAttribute("username", username);
      response.sendRedirect(request.getContextPath()+"/success.jsp");
    }
    else 
    {
      //校验失败
      response.sendRedirect(request.getContextPath()+"/failure.jsp");
    }
  }

  /**
   * Initialization of the servlet. 

   *
   * @throws ServletException if an error occurs
   */
  public void init() throws ServletException {
    // Put your code here
  }

}

<&＃63;xml version="1.0" encoding="UTF-8"&＃63;>

 
 
  This is the description of my J2EE component
  This is the display name of my J2EE component
  LoginServlet
  com.cityhuntshou.servlet.LoginServlet
 

 
  LoginServlet
  /servlet/LoginServlet
   
 
  index.jsp
 
  
    LoginFilter
    com.cityhuntshou.filter.LoginFilter
    
      noLoginPaths
      login.jsp;failure.jsp;loginServlet
    
    
      charset
      UTF-8
    
  
  
    LoginFilter
    /*