jsp+过滤器实现跳过登录拦截功能
login.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<table>
<form action="/servlet/loginservlet" method="post">
<tr>
<td>用户名:</td>
<td><input type="text" name="username"></td>
</tr>
<tr>
<td><input type="submit"></td>
</tr>
</form>
</table>
</body>
</html>
success.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<h1><%=session.getAttribute("username")%>，欢迎您</h1>
<a href="/servlet/loginoutservlet">退出登录</a>
</body>
</html>
error.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<h2>权限不足</h2>
<a href="login.jsp">请重新登录</a>
</body>
</html>
过滤器succFilter.java
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class succFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
HttpServletRequest request=(HttpServletRequest)servletRequest;
HttpServletResponse response=(HttpServletResponse)servletResponse;
if(request.getSession().getAttribute("username")==null){
response.sendRedirect("/error.jsp");
}
filterChain.doFilter(request,response);
}
@Override
public void destroy() {
}
}
退出servlet
package servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class loginoutservlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String username = (String) req.getSession().getAttribute("username");
if(username!=null){
req.getSession().removeAttribute("username");
resp.sendRedirect("/login.jsp");
}else {
resp.sendRedirect("/login.jsp");
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
}
登录验证servlet
package servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class loginservlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String username = req.getParameter("username");
if("admin".equals(username)){
req.getSession().setAttribute("username",username);
String username1 = (String) req.getSession().getAttribute("username");
resp.sendRedirect("/success/success.jsp");
}else {
resp.sendRedirect("/error.jsp");
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
}
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
<servlet-name>loginservlet</servlet-name>
<servlet-class>servlet.loginservlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>loginservlet</servlet-name>
<url-pattern>/servlet/loginservlet</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>loginoutservlet</servlet-name>
<servlet-class>servlet.loginoutservlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>loginoutservlet</servlet-name>
<url-pattern>/servlet/loginoutservlet</url-pattern>
</servlet-mapping>
<filter>
<filter-name>succFilter</filter-name>
<filter-class>filter.succFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>succFilter</filter-name>
<url-pattern>/success/*</url-pattern>
</filter-mapping>
</web-app>
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.liu</groupId>
<artifactId>javaweb-login</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>javax.servlet.jsp-api</artifactId>
<version>2.3.3</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>taglibs</groupId>
<artifactId>standard</artifactId>
<version>1.1.2</version>
</dependency>
</dependencies>
</project>
项目结构
