Filter实现表单登陆过滤验证

来源：互联网发布：与该网络签署协议编辑：程序博客网时间：2024/05/21 19:40

1:login.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<font color="red">${message}</font><br/><br/>
<form action="hello.jsp" method="post">
userName:<input type="text" name="username" value="${param.username}"/><br/>
passWord:<input type="password" name="password"/><br/>
<input type="submit" value="登录"/>
</form>
</body>
</html>

2:web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
<display-name>Filter</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<filter>
<filter-name>helloFilter</filter-name>
<filter-class>com.filter.HelloFilter</filter-class>
<init-param>
<param-name>name</param-name>
<param-value>root</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>helloFilter</filter-name>
<url-pattern>/test.jsp</url-pattern>
</filter-mapping>
<filter>
<filter-name>secondFilter</filter-name>
<filter-class>com.filter.SecondFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>secondFilter</filter-name>
<url-pattern>/test.jsp</url-pattern>
</filter-mapping>
<filter>
<filter-name>UserNameFilter</filter-name>
<filter-class>com.filter.UserNameFilter</filter-class>
<init-param>
<param-name>username</param-name>
<param-value>Tom</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>UserNameFilter</filter-name>
<url-pattern>/hello.jsp</url-pattern>
</filter-mapping>
<filter>
<filter-name>PasswordFilter</filter-name>
<filter-class>com.filter.PasswordFilter</filter-class>
<init-param>
<param-name>password</param-name>
<param-value>12345</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>PasswordFilter</filter-name>
<url-pattern>/hello.jsp</url-pattern>
</filter-mapping>
</web-app>

3:UserNameFilter

package com.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 UserNameFilter implements Filter {
private FilterConfig fConfig=null;
public UserNameFilter() {
}
public void destroy() {
System.out.println("destory...");
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
String initUsername=fConfig.getInitParameter("username");
String username=request.getParameter("username");
if(!initUsername.equals(username))
{
request.setAttribute("message", "用户名不正确!");
request.getRequestDispatcher("/login.jsp").forward(request, response);
}
chain.doFilter(request, response);

}

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

}

4:PasswordFilter

package com.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 PasswordFilter implements Filter {
private FilterConfig fConfig=null;
public PasswordFilter() {
}
public void destroy() {
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
String initPassword=fConfig.getInitParameter("password");
String password=request.getParameter("password");
if(!initPassword.equals(password))
{
request.setAttribute("message", "密码不正确!");
request.getRequestDispatcher("/login.jsp").forward(request, response);
}
chain.doFilter(request, response);
}

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

}

5:hello.sjp

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