package com.filter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
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 StateFilter implements Filter {
private ArrayList<String> list = new ArrayList();
@Override
public void destroy() {
// TODO 自动生成的方法存根
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest)request;
HttpServletResponse rep=(HttpServletResponse)response;
HttpSession session = req.getSession();
String path1=req.getRequestURI();
String path2=req.getContextPath();
String target =path1.substring(path2.length());
if(list.contains(target)==false){
if(session.getAttribute("user")==null){
rep.sendRedirect("login.jsp");
}
else{
chain.doFilter(req, rep);
}
}
else{
chain.doFilter(req, rep);
}
}
@Override
public void init(FilterConfig cfg) throws ServletException {
String val=cfg.getInitParameter("allowpage");
String[] arr=val.split(",");
list.addAll(Arrays.asList(arr));
}
}
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;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class TestFilter implements Filter{
@Override
public void destroy() {
// TODO 自动生成的方法存根
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
// TODO 自动生成的方法存根
//HttpServletRequest req=(HttpServletRequest)request;
//HttpServletResponse rep = (HttpServletResponse)response;
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
//response.getWriter().write("kaishi");
chain.doFilter(request, response);
//response.getWriter().write("jieshu");
}
@Override
public void init(FilterConfig arg0) throws ServletException {
// TODO 自动生成的方法存根
}
}
<?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">
<filter>
<filter-name>testfilter</filter-name>
<filter-class>com.filter.TestFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>testfilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter>
<filter-name>loginfilter</filter-name>
<filter-class>com.filter.StateFilter</filter-class>
<init-param>
<param-name>allowpage</param-name>
<param-value>/login.jsp,/login</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>loginfilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<display-name>Test0213am</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>
login.jsp界面:
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h1>1aasdasd</h1>
</body>
</html>
NewFile.jsp界面:
<%@ 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>
<h2>JSP文件</h2>
</body>
</html>

在地址栏输入除了login和login.jsp之外任何地址都跳转到login.jsp界面

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