java web 课上实验
一、对站点应用filter几时，是局域网中指定IP地址不能访问你的网站，其它IP地址可以
二、使用过滤器处理中文乱码问题
三、未登录的用户不能看见页面中的图片，登录之后才能看见
第一题：
filter文件：
package ch06;
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;
/**
* 定义IpFilter过滤器，过滤掉自己配置的ip列表禁止访问系统
* ip列表在配置的filter中加入初始化参数即可。
* @author Administrator
*
*/
public class IP_filter implements Filter{
String [] forbidIps = null;
@Override
public void destroy() {
// TODO Auto-generated method stub
}
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain filterChain) throws IOException, ServletException {
//由于拦截器定义的拦截规范是/* ,所以所有的请求都会被拦截，为了防止死循环 开一个特例显示具体的访问结果
if(((HttpServletRequest)request).getRequestURI().contains("forbid.jsp")){
filterChain.doFilter(request, response);
return;//不加return 会继续执行请求。
}
String remoteAddr = request.getRemoteAddr(); //获取客户端IP地址进行比较
if(forbidIps!=null){
for (int i=0; i<forbidIps.length; i++) {
if(forbidIps[i].equals(remoteAddr)){
//如果访问的ip与配置的ip相等 则直接过滤掉。
((HttpServletResponse)response).sendRedirect("error.jsp");
return;
}
}
}
filterChain.doFilter(request, response);
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
//获取在web.xml中配置的<filter>的初始化参数
String initParamter = filterConfig.getInitParameter("forbidIps");
if(initParamter != null){
forbidIps = initParamter.split(",");
}
}
}
XML文件：
<web-app>
<filter>
<display-name>IP_filter</display-name>
<filter-name>IP_filter</filter-name>
<filter-class>ch06.IP_filter</filter-class>
<init-param>
<param-name>forbidIps</param-name>
<param-value>192.168.12.133,192.168.6.99</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>IP_filter</filter-name>
<url-pattern>/IP.jsp</url-pattern>
</filter-mapping>
</web-app>
JSP文件:
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>只有没有过滤的IP才能访问</title>
</head>
<body>
hello
</body>
</html>
第二题：
JSP文件：
<%@ 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>中文乱码</title>
</head>
<body>
<%
System.out.println(request.getContextPath());
%>
<form action="ZhonWentijiao" method="post">
<input type="text" name="username"><br/>
<input type="submit" value="提交">
</form>
</body>
</html>
Filter文件：
package ch06;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class ZhonWenfile 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;
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
filterChain.doFilter(request,response);
}
@Override
public void destroy() {
}
}
servlet文件：
package ch06;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
* Created by YYBJ on 2018/9/18.
* ZCL
*/
public class ZhonWentijiao extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String munber = req.getParameter("munber");
System.out.println("username===="+munber);
resp.getWriter().write(munber);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
}
XML文件：
<servlet>
<description></description>
<display-name>ZhonWentijiao</display-name>
<servlet-name>ZhonWentijiao</servlet-name>
<servlet-class>ch06.ZhonWentijiao</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ZhonWentijiao</servlet-name>
<url-pattern>/ZhonWentijiao</url-pattern>
</servlet-mapping>
<filter>
<display-name>ZhonWenfile</display-name>
<filter-name>ZhonWenfile</filter-name>
<filter-class>ch06.ZhonWenfile</filter-class>
</filter>
<filter-mapping>
<filter-name>ZhonWenfile</filter-name>
<url-pattern>/ZhonWentijiao</url-pattern>
</filter-mapping>
第三题：
JSP文件：
<%@ page language="java" import="java.awt.Image" import="java.io.FileInputStream" import="java.io.FileNotFoundException" import="java.awt.image.BufferedImage" import="java.util.Iterator" import="java.io.File" import="javax.imageio.stream.ImageInputStream" import="javax.imageio.ImageIO" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html"; charset=UTF-8>
<title>
Insert titile here
</title>
</head>
<body>
<form action="Loginsave" method="post" >
用户名：<input type="text" name="username" /><br>
密 码：<input type="password" name="password" /><br>
<input type="submit" value="登录" />
</form>
</body>
</html>
servlet文件：
package ch06;
import java.io.*;
import javax.servlet.ServletException;
import javax.servlet.http.*;
public class Loginsave extends HttpServlet {
private static final long serialVersionUID = 1L;
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter(); //输出流
String username = (String) request.getParameter("username"); //从html文件中获取用户名密码,cookie时间
String password = (String) request.getParameter("password");
Users user = new Users(); //构造用户对象的方法
user.setUsername(username); //写入用户对象方法
user.setPassword(password);
request.getSession().setAttribute("user", user); //将用户名保存在session中
response.sendRedirect("xianshitupian.jsp"); //转到登陆页面
}
public void doPost(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException{
doGet(request,response);
}
}
User类对象：
package ch06;
public class Users { //用户对象
private String username;
private String password;
private String time;
public String getUsername() {
return username;
}
public void setUsername(String username) { //用户对象写入方法
this.username = username;
}
public String getPassword() { //用户对象获取方法
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
Filter文件：
package ch06;
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;
/**
* Servlet Filter implementation class LoginChecs
*/
public class LoginChecs implements Filter {
/**
* Default constructor.
*/
public LoginChecs() {
// TODO Auto-generated constructor stub
}
/**
* @see Filter#destroy()
*/
public void destroy() {
// TODO Auto-generated method stub
}
/**
* @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
*/
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) servletRequest;
HttpServletResponse response = (HttpServletResponse) servletResponse;
// 获得session
HttpSession session = request.getSession(); //使用session对象
// 从session中获取SessionKey对应值,若值不存在,则重定向到redirectUrl
Object users = session.getAttribute("user");
System.out.println("username===="+users);
if (users != null) {
request.getSession().removeAttribute("user"); //从session中删除用户名记录
filterChain.doFilter(request, response);
} else {
response.sendRedirect("error.jsp");
}
}
/**
* @see Filter#init(FilterConfig)
*/
public void init(FilterConfig fConfig) throws ServletException {
// TODO Auto-generated method stub
}
}
