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【Java学习20170427】Servlet过滤器和监听器

2017-04-27 18:52 375 查看
JavaWeb

Servlet过滤器和监听器















package com.tx.demo2;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

/**
* 统计过滤器
*/
public class CountFilter implements Filter {
// 来访数量
private int count;

@Override
public void init(FilterConfig filterConfig) throws ServletException {
// 获取初始化参数
String param = filterConfig.getInitParameter("count");
// 将字符串转换为int
count = Integer.valueOf(param);
}

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
// 访问数量自增
count++;
// 将ServletRequest转换成HttpServletRequest
HttpServletRequest req = (HttpServletRequest) request;
// 获取ServletContext
ServletContext context = req.getSession().getServletContext();
// 将来访数量值放入到ServletContext中
context.setAttribute("count", count);
// 向下传递过滤器
chain.doFilter(request, response);
}

@Override
public void destroy() {
}
}

<%@ 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>人数统计</title>
</head>
<body>
<h2>
欢迎光临，<br>
您是本站的第【
<%=application.getAttribute("count") %>
】位访客！
</h2>
</body>
</html>

<?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>FilerTest</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-f
4000
ile>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<!-- 过滤器声明 -->
<filter>
<!-- 过滤器的名称 -->
<filter-name>CountFilter</filter-name>
<!-- 过滤器的完整类名 -->
<filter-class>com.tx.demo2.CountFilter</filter-class>
<!-- 设置初始化参数 -->
<init-param>
<!-- 参数名 -->
<param-name>count</param-name>
<!-- 参数值 -->
<param-value>5000</param-value>
</init-param>
</filter>
<!-- 过滤器映射 -->
<filter-mapping>
<!-- 过滤器名称 -->
<filter-name>CountFilter</filter-name>
<!-- 过滤器URL映射 -->
<url-pattern>/index.jsp</url-pattern>
</filter-mapping>

</web-app>





package com.tx.demo3;

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;

/**
* 添加图书信息的Servlet
*/
public class AddServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

// 处理GET请求
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}

// 处理POST请求
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 获取 PrintWriter
PrintWriter out = response.getWriter();
// 获取图书编号
String id = request.getParameter("id");
// 获取名称
String name = request.getParameter("name");
// 获取作者
String author = request.getParameter("author");
// 获取价格
String price = request.getParameter("price");
// 输出图书信息
out.print("<h2>图书信息添加成功</h2><hr>");
out.print("图书编号：" + id + "<br>");
out.print("图书名称：" + name + "<br>");
out.print("作者：" + author + "<br>");
out.print("价格：" + price + "<br>");
// 刷新流
out.flush();
// 关闭流
out.close();
}
}

package com.tx.demo3;

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;
// 字符编码过滤器
public class CharactorFilter implements Filter {
// 字符编码
String encoding = null;
@Override
public void destroy() {
encoding = null;
}

@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
// 判断字符编码是否为空
if(encoding != null){
// 设置request的编码格式
request.setCharacterEncoding(encoding);
// 设置response字符编码
response.setContentType("text/html; charset="+encoding);
}
// 传递给下一过滤器
chain.doFilter(request, response);
}

@Override
public void init(FilterConfig filterConfig) throws ServletException {
// 获取初始化参数
encoding = filterConfig.getInitParameter("encoding");
}

}

<%@ 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>添加图书信息</title>
</head>
<body>
<form action="AddServlet" method="get">
<table align="center" border="1" width="350">
<tr>
<td class="2" align="center" colspan="2">
<h2>添加图书信息</h2>
</td>
</tr>
<tr>
<td align="right">图书编号：</td>
<td>
<input type="text" name="id">
</td>
</tr>
<tr>
<td align="right">图书名称：</td>
<td>
<input type="text" name="name">
</td>
</tr>
<tr>
<td align="right">作　　者：</td>
<td>
<input type="text" name="author">
</td>
</tr>
<tr>
<td align="right">价　　格：</td>
<td>
<input type="text" name="price">
</td>
</tr>
<tr>
<td class="2" align="center" colspan="2">
<input type="submit" value="添　加">
</td>
</tr>
</table>
</form>
</body>
</html>

<?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>FilerTest2</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>
<!-- 声明过滤器 -->
<filter>
<!-- 过滤器名称 -->
<filter-name>CharactorFilter</filter-name>
<!-- 过滤器的完整类名 -->
<filter-class>com.tx.demo3.CharactorFilter</filter-class>
<!-- 初始化参数 -->
<init-param>
<!-- 参数名 -->
<param-name>encoding</param-name>
<!-- 参数值 -->
<param-value>UTF-8</param-value>
</init-param>
</filter>
<!-- 过滤器映射 -->
<filter-mapping>
<!-- 过滤器名称 -->
<filter-name>CharactorFilter</filter-name>
<!-- URL映射 -->
<url-pattern>/*</url-pattern>
</filter-mapping>
<!-- 声明Servlet -->
<servlet>
<!-- Servlet名称 -->
<servlet-name>AddServlet</servlet-name>
<!-- Servlet完整类名 -->
<servlet-class>com.tx.demo3.AddServlet</servlet-class>
</servlet>
<!-- Servlet映射 -->
<servlet-mapping>
<!-- Servlet名称 -->
<servlet-name>AddServlet</servlet-name>
<!-- URL映射 -->
<url-pattern>/AddServlet</url-pattern>
</servlet-mapping>
</web-app>




package com.tx.listener;

import java.util.*;

public class LoginList {
private static LoginList user = new LoginList();
private Vector<String> vector = null;

// private调用构造函数，
// 防止被外界类调用产生新的instance对象
private LoginList() {
this.vector = new Vector<String>();
}

// 外界使用的instance对象
public static LoginList getInstance() {
return user;
}

// 用户登录
public boolean addLoginList(String user) {
if (user != null) {
this.vector.add(user);
return true;
} else {
return false;
}
}

// 获取用户列表
public Vector<String> getList() {
return vector;
}

// 删除用户
public void removeLoginList(String user) {
if (user != null) {
vector.removeElement(user);
}
}
}

package com.tx.listener;

import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionBindingListener;

public class LoginNote implements HttpSessionBindingListener {
private String user;
private LoginList container = LoginList.getInstance();

public LoginNote() {
user = "";
}

public void setUser(String user) {
this.user = user;
}

public String getUser() {
return this.user;
}

public void valueBound(HttpSessionBindingEvent arg0) {
System.out.println(this.user + "该用户己经上线");
}

public void valueUnbound(HttpSessionBindingEvent arg0) {
System.out.println(this.user + "该用户己经下线");
if (user != "") {
container.removeLoginList(user);
}
}
}









文件上传
package com.share.putfile;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;

import org.apache.catalina.core.ApplicationPart;

/**
* Servlet implementation class UploadServlet
*/
@WebServlet("/UploadServlet")
@MultipartConfig()
public class UploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {

request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
String path = this.getServletContext().getRealPath("/"); //获取服务器地址
Part p = request.getPart("file1"); //获取用户选择的上传文件
if (p.getContentType().contains("image")) { // 仅处理上传的图像文件
ApplicationPart ap = (ApplicationPart) p;
System.out.println(ap.getHeaderNames());
System.out.println(ap.getHeader("content-disposition"));
// String fname1 = ap.getFilename(); //获取上传文件名
// int path_idx = fname1.lastIndexOf("\\") + 1; //对上传文件名进行截取
// String fname2 = fname1.substring(path_idx, fname1.length());

String content = ap.getHeader("content-disposition");
String fname1 = content.substring(content.lastIndexOf("\\")+1);
fname1 = fname1.substring(0, fname1.length()-1);
File file = new File(path + "/upload/" + fname1);
p.write(file.getPath()); // 写入 web 项目根路径下的upload文件夹中
out.write("文件上传成功");
}
else{
out.write("请选择图片文件！！！");
}
}
}

<%@ 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>Insert title here</title>
</head>
<body>
<form action="UploadServlet" enctype="multipart/form-data" method ="post" >
选择文件<input type="file" name="file1" />
<input type="submit" name="upload" value="上传" />
</form>
</body>
</html>
Filter 和Servlet实现用户角色验证1
package com.tx.control;

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.annotation.WebFilter;
import javax.servlet.http.HttpServletResponse;

@WebFilter(value="/tx")
public class MyFile_1 implements Filter {

@Override
public void destroy() {
// TODO Auto-generated method stub

}

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
// TODO Auto-generated method stub
String people = request.getParameter("user");
if("teacher".equals(people)){
chain.doFilter(request, response);//放行
}else{
((HttpServletResponse)response).sendRedirect("/FilerWebTest3/error.html");
}
}

@Override
public void init(FilterConfig arg0) throws ServletException {
// TODO Auto-generated method stub

}

}


package com.tx.control;

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.annotation.WebFilter;
import javax.servlet.http.HttpServletResponse;

@WebFilter(value="/tx/test.do")
public class MyFile_2 implements Filter{

@Override
public void destroy() {
// TODO Auto-generated method stub

}

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
// TODO Auto-generated method stub

String username = request.getParameter("username");
if("tx".equals(username)){
chain.doFilter(request, response);
}else{
((HttpServletResponse)response).sendRedirect("/FilerWebTest3/error.html");
}

}

@Override
public void init(FilterConfig arg0) throws ServletException {
// TODO Auto-generated method stub

}

}

package com.tx.control;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(value="/tx/test.do")
public class MyServlet extends HttpServlet{

@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

// 设置request的编码
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html; charset=utf-8");
String username = request.getParameter("username");
String password = request.getParameter("password");
PrintWriter pw = response.getWriter();
pw.println("账号："+username+"密码："+password);
pw.flush();
pw.close();

}

}
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="tx/test.do" method="post">
<select name="user">
<option value="student">学生</option>
<option value="teacher">老师</option>
</select>
<br/>
用户名：<input name="username" type="text" >
<br>
密码： <input name="password" type="text">
<br>
<input type="submit" value="登录">
</form>
</body>
</html>


<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
没有访问权限
</body>
</html>


Filter 和Servlet实现用户权限角色验证
package com.tx.util;

import java.util.Hashtable;

public class Jurisdiction {
/** 管理员*/
private Hashtable<String,String> administrator;
/** 开发人员*/
private Hashtable<String,String> engineer;
/** 游客*/
private Hashtable<String,String> visitor;

private Hashtable<String,String> people;

//初始化代码块
{
administrator = new Hashtable<String,String>();
engineer = new Hashtable<String,String>();
visitor = new Hashtable<String,String>();
people = new Hashtable<String,String>();
init();
}

private static Jurisdiction
aeff
j;

static {
j = new Jurisdiction();
}

public static Jurisdiction getnewInstance(){
return j;
}

private Jurisdiction(){}

/**
* 初始化
*/
public void init(){
administrator.put("王二狗", "123465");
engineer.put("帅哥", "123");
visitor.put("user", "112233");
people.putAll(administrator);
people.putAll(engineer);
people.putAll(visitor);
}

/**
* 检查权限等级
* @param username
* @return
*/
public int examine(String username){
if(administrator.containsKey(username)){
return 1;
}else if(engineer.containsKey(username)){
return 2;
}else if(visitor.containsKey(username)){
return 3;
}else {
return 4;
}
}

public Hashtable<String, String> getAdministrator() {
return administrator;
}

public Hashtable<String, String> getEngineer() {
return engineer;
}

public Hashtable<String, String> getVisitor() {
return visitor;
}

public Hashtable<String, String> getPeople() {
return people;
}

}


package com.tx.action;

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.annotation.WebFilter;

@WebFilter(value = "/*")
public class CharactorFilter implements Filter {

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
System.out.println("DoFilter");
// 设置request的编码格式
request.setCharacterEncoding("UTF-8");
// 设置response字符编码
response.setContentType("text/html; charset=UTF-8");
// 传递给下一过滤器
chain.doFilter(request, response);
}

@Override
public void init(FilterConfig filterConfig) throws ServletException {
}

@Override
public void destroy() {

}

}

package com.tx.action;

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.annotation.WebFilter;
import javax.servlet.http.HttpServletResponse;

import com.tx.util.Jurisdiction;

@WebFilter(value = "/show.do")
public class MyFilter implements Filter {

@Override
public void destroy() {
// TODO Auto-generated method stub

}

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
Jurisdiction j = Jurisdiction.getnewInstance();
String username = request.getParameter("user");
String password = request.getParameter("password");
switch (j.examine(username)) {
case 1:
if (j.getAdministrator().containsValue(password)) {
request.getRequestDispatcher("WEB-INF/jsp/admin.jsp").forward(request, response);
} else {
request.getRequestDispatcher("WEB-INF/jsp/error.html").forward(request, response);
}
break;
case 2:
if (j.getEngineer().containsValue(password)) {
request.getRequestDispatcher("WEB-INF/jsp/engineer.jsp").forward(request, response);
} else {
request.getRequestDispatcher("WEB-INF/jsp/error.html").forward(request, response);
}
break;
case 3:
if (j.getVisitor().containsValue(password)) {
request.getRequestDispatcher("WEB-INF/jsp/visitor.jsp").forward(request, response);
} else {
request.getRequestDispatcher("WEB-INF/jsp/error.html").forward(request, response);
}
break;

default:
request.getRequestDispatcher("WEB-INF/jsp/warning.html").forward(request, response);
break;
}

}

@Override
public void init(FilterConfig arg0) throws ServletException {
// TODO Auto-generated method stub

}

}

package com.tx.action;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(value="/show.do")
public class MyServlet extends HttpServlet{

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
doPost(req,resp);

}

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
PrintWriter pw = resp.getWriter();
pw.println("逻辑出错");
pw.flush();
pw.close();
}

}

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="show.do" method="post" >

<table align=center border="1">
<caption>欢迎来到XXX后台系统</caption>
<tr>
<td>账号：</td>
<td><input type="text" name="user"></td>
</tr>
<tr>
<td>密码：</td>
<td><input type="password" name="password"></td>
</tr>
<tr align="center">
<td colspan="2"><input type="submit" value="登录"></td>
</tr>
</table>

</form>
</body>
</html>


以下文件放在WebRoot---WEB-INF（为了防止用户根据链接拼接接入）
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1 align="center">无访问权限，请联系管理员</h1>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h3 align="center">账号或密码错误</h3>
</body>
</html>

<%@page import="java.util.Map"%>
<%@page import="java.util.Set"%>
<%@page import="java.util.Hashtable"%>
<%@page import="com.tx.util.Jurisdiction"%>
<%@ 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>
<table>
<%
Jurisdiction j = Jurisdiction.getnewInstance();
Hashtable<String, String> admin = j.getPeople();
Set<Map.Entry<String, String>> s = admin.entrySet();
for (Map.Entry<String, String> e : s) {
out.println("<tr>");
out.println("<td>账号：" + e.getKey() + "</td><td>密码：" + e.getValue() + "</td>");
out.println("</tr>");
}
%>
<tr>
<td><input type="button" value="删除"></td>
</tr>
</table>
</body>
</html>

<%@ 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>
<%
String name = request.getParameter("user");
String password = request.getParameter("password");
%>
<table>
<tr>
<td>
账号：<%=name %>
</td>
</tr>
<tr>
<td>
密码：<%=password %>
</td>
</tr>
<tr>
<td>
<input type="button" value="修改">
</td>
</tr>
</table>
</body>
</html>

<%@ 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>
<%
String name = request.getParameter("user");
String password = request.getParameter("password");
%>
<table>
<tr>
<td>
账号：<%=name %>
</td>
</tr>
<tr>
<td>
密码：<%=password %>
</td>
</tr>
</table>
</body>
</html>
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