• jsp2


    JSP内置对象
    1：内置对象简介
      JSP内置对象是WEB容器创建的一组对象，不是用new 关键就可以使用的
    2：四种作用域范围
    3：out
    4:request/response
    5:seession
    6:applicaton
    7:其他

        
    JSP内置对象是WEB容器中创建的一组对象，可以直接使用不需要new，如截图中的out 对象



    五大常用对象： out、request、response、session、application<br>
    其它四个不常用对象：page、pageContext、exception、config
    1. <%@ page language="java" import="java.util.*" contentType="text/html; charset=UTF-8"%>
    2. <%
    3. String path = request.getContextPath();
    4. String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    5. %>
    7. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    8. <html>
    9.   <head>
    10.     <base href="<%=basePath%>">
    11.     
    12.     <title>My JSP 'MyJsp.jsp' starting page</title>
    13.     
    14. 	<meta http-equiv="pragma" content="no-cache">
    15. 	<meta http-equiv="cache-control" content="no-cache">
    16. 	<meta http-equiv="expires" content="0">    
    17. 	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    18. 	<meta http-equiv="description" content="This is my page">
    19. 	<!--
    20. 	<link rel="stylesheet" type="text/css" href="styles.css">
    21. 	-->
    23.   </head>
    24.   
    25.   <body>
    26.    
       <h1>out内置对象</h1>
          <%
          //clear()清除缓冲区
          out.println("<h2>静夜思</h2>");
          out.println("床前明月光<br>");
          out.println("床前明月光<br>");
          out.flush();//没任何区别输出，缓冲区变大，调用clear()的话，会打印前几句，false
          //clearBuffer() 不会抛出异常
          out.println("床前明月光<br>");
          out.println("床前明月光<br>");
          %>
          缓冲区大小:<%=out.getBufferSize() %>byte<br>
          缓冲区剩余大小：<%=out.getRemaining() %>byte<br>
        是否清空缓冲区：<%=out.isAutoFlush() %><br>
        </body>
    27. </html>

    1. <%@ page language="java" import="java.util.*"
    2. 	contentType="text/html; charset=UTF-8"%>
    3. <%
    4. 	String path = request.getContextPath();
    5. 	String basePath = request.getScheme() + "://"
    6. 			+ request.getServerName() + ":" + request.getServerPort()
    7. 			+ path + "/";
    8. %>
    10. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    11. <html>
    12. <head>
    13. <base href="<%=basePath%>">
    15. <title>My JSP 'login.jsp' starting page</title>
    17. <meta http-equiv="pragma" content="no-cache">
    18. <meta http-equiv="cache-control" content="no-cache">
    19. <meta http-equiv="expires" content="0">
    20. <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    21. <meta http-equiv="description" content="This is my page">
    22. <!--
    23. 	<link rel="stylesheet" type="text/css" href="styles.css">
    24. 	-->
    26. </head>
    28. <body>
    29. 	<h1>用户登录</h1>
    30. 	<hr> 
    31. 	<from action="dologin.jsp" name="loginForm" method="get"><%--post --%>
    32. 	<table>
    33. 		<tr>
    34. 			<td>用户名:</td>
    35. 			<td><input type="text" name="username"></td>
    36. 		</tr>
    37. 		<tr>
    38. 			<td>密码:</td>
    39. 			<td><input type="password" name="password"></td>
    40. 		</tr>
    41. 		<tr>
    42. 			<td colspan="2"><input type="submit" value="登陆"></td>
    43. 		</tr>
    44. 	</table>
    45. 	</from>
    46. </body>
    47. </html>

    1. <body>
    2.    <h1>登陆成功</h1>
    3.    <hr>
    4.   </body>


    1. <%@ page language="java" import="java.util.*"
    2. 	contentType="text/html; charset=UTF-8"%>
    3. <%
    4. 	String path = request.getContextPath();
    5. 	String basePath = request.getScheme() + "://"
    6. 			+ request.getServerName() + ":" + request.getServerPort()
    7. 			+ path + "/";
    8. %>
    10. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    11. <html>
    12. <head>
    13. <base href="<%=basePath%>">
    15. <title>My JSP 'req.jsp' starting page</title>
    17. <meta http-equiv="pragma" content="no-cache">
    18. <meta http-equiv="cache-control" content="no-cache">
    19. <meta http-equiv="expires" content="0">
    20. <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    21. <meta http-equiv="description" content="This is my page">
    22. <!--
    23. 	<link rel="stylesheet" type="text/css" href="styles.css">
    24. 	-->
    26. </head>
    28. <body>
    29. 	<h1>用户注册</h1>
    30. 	<hr>
    31. 	<form name="regForm" action="request.jsp" method="post">
    32. 		<table>
    33. 			<tr>
    34. 				<td>用户名:</td>
    35. 				<td><input type="text" name="username"></td>
    36. 			</tr>
    37. 			<tr>
    38. 				<td>爱好:</td>
    39. 				<td><input type="checkbox" name="favorite" value="read">读书
    40. 					<input type="checkbox" name="favorite" value="music">音乐 <input
    41. 					type="checkbox" name="favorite" value="movie">电影 <input
    42. 					type="checkbox" name="favorite" value="internet">上网</td>
    43. 			</tr>
    44. 			<tr>
    45. 				<td colspan="2"><input type="submit" value="登陆"></td>
    46. 			</tr>
    47. 		</table>
    48. 	</form>
    49. 	<br>
    50. 	<a href="request.jsp?username=lisi"> 测试url传参</a>  <!-- 中文“李四”会出问题，通过tomcat-conf-server-Connector标签+URLEncoding="utf-8"-重启tomcat -->
    51. </body>
    52. </html>
    1. <body>
    3. 	<h1>requst内置对象</h1>
    4. 	<%
    5. 		request.setCharacterEncoding("utf-8");//可以提交汉字
    6. 		request.setAttribute("password", "123456");
    7. 	%>
    8. 	用户名:<%=request.getParameter("username")%><br> 爱好：<%
    9. 		if (request.getParameterValues("favorite") != null) {
    10. 			String[] favorites = request.getParameterValues("favorite");
    11. 			for (int i = 0; i < favorites.length; i++) {
    12. 				out.println(favorites[i] + "&nbsp;");
    13. 			}
    14. 		}
    15. 	%><br> 密码：<%=request.getAttribute("password")%><br>
    16. 	请求体的MIME类型：<%=request.getContentType()%><br> 协议类型及版本号：<%=request.getProtocol()%><br>
    17. 	服务器主机名：<%=request.getServerName()%><br> 服务器端口号：<%=request.getServerPort()%><br>
    18. 	请求文件的长度（字节）：<%=request.getContentLength()%><br> 请求客户端的ip地址：<%=request.getRemoteAddr()%><br>
    19. 	请求真实路径 ：<%=request.getRealPath("request.jsp")%><br> 请求上下文路径：<%=request.getContextPath()%><br>
    20. </body>
    response对象
    -
    1. <%@page import="java.io.PrintWriter"%>
    2. <%@ page language="java" import="java.util.*"
    3. 	contentType="text/html; charset=UTF-8"%>
    4. <%
    5. 	response.setContentType("text/html; charset=UTF-8");//设置的响应的MIMI类型
    6. 	out.println("<h1>reponse内置对象</h1>");
    7. 	out.println("<br>tttt");
    8. 	PrintWriter out = response.getWriter();//获取输出流对象
    9. 	outer.println("大家好，我是response输出流");//输出 提前与内置out，用.fluse(清缓存)可以将out提前
    10. 	response.sendRedirect("reg.jsp");//请求重定向（直接跳转）
    1. %>
    -请求重定向
      客户端行为-----response.sendRedirect(),两次请求，地址栏地址改变
    -请求转发
      服务器行为-----request.getRequestDispatcher().forward(req,resp);地址不改变
    1. <body>
    2. 	<h1>用户注册</h1>
    3. 	<hr>
    4. 	<form name="regForm" action="response.jsp" method="post">
    5.           <-- action="response.jsp"-->
    6. 		<table>
    7. 			<tr>
    8. 				<td>用户名:</td>
    9. 				<td><input type="text" name="username"></td>
    10. 			</tr>
    11. 			<tr>
    12. 				<td>爱好:</td>
    13. 				<td><input type="checkbox" name="favorite" value="read">读书
    14. 					<input type="checkbox" name="favorite" value="music">音乐 <input
    15. 					type="checkbox" name="favorite" value="movie">电影 <input
    16. 					type="checkbox" name="favorite" value="internet">上网</td>
    17. 			</tr>
    18. 			<tr>
    19. 				<td colspan="2"><input type="submit" value="登陆"></td>
    20. 			</tr>
    21. 		</table>
    22. 	</form>
    23. 	<br>
    24. 	<a href="request.jsp?username=lisi"> 测试url传参</a>
    25. 	<!-- 中文“李四”会出问题，通过tomcat-conf-server-Connector标签+URLEncoding="utf-8"-重启tomcat -->
    26. </body>

    1. <%@page import="java.io.*,java.util.*"%>
    2. <%@ page language="java" import="java.util.*"
    3. 	contentType="text/html; charset=UTF-8"%>
    4. <%
    5. 	response.setContentType("text/html; charset=UTF-8");//设置的响应的MIMI类型
    6. 	out.println("<h1>reponse内置对象</h1>");
    7. 	out.println("<br>tttt");
    8. 	PrintWriter outer = response.getWriter();//获取输出流对象
    9. 	outer.println("大家好，我是response输出流");//输出 提前与内置out，用.fluse(清缓存)可以将out提前
    10. 	//response.sendRedirect("reg.jsp");//请求重定向（直接跳转）
    11. 	//请求重定向	response.sendRedirect("request.jsp");
    12. 	//请求转发
    13. 	request.getRequestDispatcher("request.jsp").forward(request, response);
    14. %>
    session
     客户端和服务器一次对话----用户浏览网站花费的时间
      在服务器内存中保存着不同用户session
                     内置对象
    1. <body>
    3. 	<h1>session内置对象</h1>
    4. 	<hr>
    5. 	<%
    6. 	SimpleDateFormat sdf=new SimpleDateFormat("yyyy年MM月dd日  HH:mm:ss");
    7. 	Date d=new Date(session.getCreationTime());/* 时间化 */
    8. 	session.setAttribute("username", "admin");
    9. 	%>
    10. 	Session创建时间：<%=sdf.format(d) %><br><!-- 直接session.getCreationTime()会出现一长串代码 -->
    11. 	Session的ID编号：<%=session.getId() %><br>
    12. 	从Session获取用户名：<%=session.getAttribute("username") %><br>
    13. </body>
    1. <body>
    3. 	<h1>session内置对象1</h1>
    4. 	<hr>
    5. 	<%
    6. 	SimpleDateFormat sdf=new SimpleDateFormat("yyyy年MM月dd日  HH:mm:ss");
    7. 	Date d=new Date(session.getCreationTime());/* 时间化 */
    8. 	session.setAttribute("username", "admin");
    9. 	session.setAttribute("password", "123456");
    10. 	session.setAttribute("age", "18");
    11. 	//设置当前session最大生成期限单位是秒
    12. 	session.setMaxInactiveInterval(10);//10s
    13. 	%>
    14. 	Session创建时间：<%=sdf.format(d) %><br><!-- 直接session.getCreationTime()会出现一长串代码 -->
    15. 	Session的ID编号：<%=session.getId() %><br>
    16. 	从Session获取用户名：<%=session.getAttribute("username") %><br>
    17. 	<a href="session2.jsp" target="_blank">用超链接跳转到Session2</a>
    18. </body>
    1. <body>
    3. 	<h1>session内置对象2</h1>
    4. 	<hr>
    5. 	<%
    6. // 	SimpleDateFormat sdf=new SimpleDateFormat("yyyy年MM月dd日  HH:mm:ss");
    7. //  Date d=new Date(session.getCreationTime());/* 时间化 */
    8. //	session.setAttribute("username", "admin"); 
    9. 	%>
    10. 	Session的ID编号：<%=session.getId()%><br> 从Session获取用户名：<%=session.getAttribute("username")%><br>
    11. 	session中保存的全部属性：<%
    12. 		String[] names = session.getValueNames();
    13. 		for (int i = 0; i < names.length; i++) {
    14. 			out.println(names[i] + "&nbsp;");
    15. 		}
    16. 	%>
    17. </body>
    session生命周期
    创建-活动-销毁
      session对象
    Tomcat默认超时30s
    .设置Session超时两种方式
     1.session.setMaxInactiveInterval(时间)//单位是秒
    2：在web.xml配置
     <session-confi> <session-timeout>10</session-timeout></session-confi>//单位分
    application
    实现用户间数据共享，可存放全局变量
    开始与服务器启动，终止服务器关闭
      public void setAttribute(String,Object)使用指定名称将对象绑定到对话
    public Object getAttribute(String)返回uzai次对话中指定名称绑定在一起的对象，没有返回null
    Enumeration getAttributeNames()返回可用属性名枚举
    String getServerInfo()返回JSP（SERVET）引擎名及版本号
    1. <%@ page language="java" import="java.util.*" contentType="text/html; charset=UTF-8"%>
    2. <%
    3. String path = request.getContextPath();
    4. String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    5. %>
    7. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    8. <html>
    9.   <head>
    10.     <base href="<%=basePath%>">
    11.     
    12.     <title>My JSP 'application.jsp' starting page</title>
    13.     
    14. 	<meta http-equiv="pragma" content="no-cache">
    15. 	<meta http-equiv="cache-control" content="no-cache">
    16. 	<meta http-equiv="expires" content="0">    
    17. 	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    18. 	<meta http-equiv="description" content="This is my page">
    19. 	<!--
    20. 	<link rel="stylesheet" type="text/css" href="styles.css">
    21. 	-->
    23.   </head>
    24.   
    25.   <body>
    26.    <h1>application内置对象</h1>
    27. 	<hr>
    28. 	<%
    29. 	application.setAttribute("city", "北京");
    30. 	application.setAttribute("postcode", "10000");
    31. 	application.setAttribute("email", "lisi@126.com");
    32. 	%>
    33. 	所在城市：<%=application.getAttribute("city") %><br>
    34. 	application所有属性：<%
    35. 	Enumeration attibute=application.getAttributeNames();
    36. 	while(attibute.hasMoreElements()){
    37. 		out.println(attibute.nextElement()+"
");
    38. 	}
    39. 	%><br>
    40. 	JSp(SERVET)引擎名及版本号:<%=application.getServerInfo() %>
    41.   </body>
    42. </html>
    Page
    指向当前JSP页面本身，java.lang.Object
    1.  
    2.   <body>
    3.     <h1>page内置对象</h1>
    4. 	<hr>
    5. 	当前page页面对象的字符串描述：<%=page.toString() %>
    6.   </body>
    PageContext
    提供对JSP页面内所有对象及名字空间的访问
    可以访问本页所在session---也可以application的某一属性
    1.  <body>
    2.     <h1>pageContext内置对象</h1>
    3. 	<hr>
    4. 	用户名是：<%=pageContext.getSession().getAttribute("username") %><br>
    5. 	<%//跳转到注册页面
    6. 	//pageContext.forward("req.jsp");
    7. 	//包含include.jsp内容
    8. 	pageContext.include("include.jsp");
    9. 	%>
    10.   </body>
    1. <%@page import="javax.enterprise.inject.New"%>
    2. <%@page import="java.text.*"%>
    3. <%@ page language="java" import="java.util.*" contentType="text/html; charset=UTF-8"%>
    4. <%
    5. String path = request.getContextPath();
    6. String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    7. Date date=new Date();
    8. SimpleDateFormat sdf=new SimpleDateFormat("yyyy年MM月dd日");
    9. String s=sdf.format(date);
    10. out.println(s+"<br>");
    11. %>

    Config
    在一个Servet初始化时，JSP引擎向它传递信息，
    Exception
    是一个异常对象，
    1. <%@ page language="java" import="java.util.*"  contentType="text/html; charset=UTF-8" errorPage="exception.jsp"%>
    2. <!--  errorPage="exception.jsp"将异常交给 exception.jsp处理 -->
    3. <%
    4. String path = request.getContextPath();
    5. String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    6. %>
    8. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    9. <html>
    10.   <head>
    11.     <base href="<%=basePath%>">
    12.     
    13.     <title>My JSP 'exception.jsp' starting page</title>
    14.     
    15. 	<meta http-equiv="pragma" content="no-cache">
    16. 	<meta http-equiv="cache-control" content="no-cache">
    17. 	<meta http-equiv="expires" content="0">    
    18. 	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    19. 	<meta http-equiv="description" content="This is my page">
    20. 	<!--
    21. 	<link rel="stylesheet" type="text/css" href="styles.css">
    22. 	-->
    24.   </head>
    25.   
    26.   <body>
    27.    <h1>测试异常页面</h1>
    28.    <%
    29.    System.out.println(100/0);//抛出算数异常
    30.    %>
    31.   </body>
    32. </html>
    1. <%@ page language="java" import="java.util.*"  contentType="text/html; charset=UTF-8" isErrorPage="true"%>
    2. <%
    3. String path = request.getContextPath();
    4. String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    5. %>
    7. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    8. <html>
    9.   <head>
    10.     <base href="<%=basePath%>">
    11.     
    12.     <title>My JSP 'excepton.jsp' starting page</title>
    13.     
    14. 	<meta http-equiv="pragma" content="no-cache">
    15. 	<meta http-equiv="cache-control" content="no-cache">
    16. 	<meta http-equiv="expires" content="0">    
    17. 	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    18. 	<meta http-equiv="description" content="This is my page">
    19. 	<!--
    20. 	<link rel="stylesheet" type="text/css" href="styles.css">
    21. 	-->
    23.   </head>
    24.   
    25.   <body>
    26.    <h1>exception内置对象</h1>
    27.    异常消息:<%=exception.getMessage() %><br>
    28.    异常字符串描述：<%=exception.toString() %>
    29.   </body>
    30. </html>
    用户登录例子：用户名admin,登陆成功内部转发login_success.jspbong提示成功，失败则请求重定向login_failure.jsp
    indexs.jsp
    1. <%@ page language="java" import="java.util.*" contentType="text/html; charset=UTF-8"%>
    2. <%
    3. 	String path = request.getContextPath();
    4. 	String basePath = request.getScheme() + "://"
    5. 			+ request.getServerName() + ":" + request.getServerPort()
    6. 			+ path + "/";
    7. %>
    9. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    10. <html>
    11. <head>
    12. <base href="<%=basePath%>">
    14. <title>My JSP 'index.jsp' starting page</title>
    15. <meta http-equiv="pragma" content="no-cache">
    16. <meta http-equiv="cache-control" content="no-cache">
    17. <meta http-equiv="expires" content="0">
    18. <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    19. <meta http-equiv="description" content="This is my page">
    20. <!--
    21. 	<link rel="stylesheet" type="text/css" href="styles.css">
    22. 	-->
    23. </head>
    25. <body>
    26. 	<div id="container">
    27. 		<div></div>
    28. 		<div id="box">
    29. 			<form action="doologin.jsp" method="post">
    30. 				<p class="main">
    31. 					<label>用户名：</label><input name="username" value="" /> 
    32. 					<label>密码：</label><input	type="possword" name="password" value="" />
    33. 				</p>
    34. 				<p cclass="space">
    35. 					<input type="submit" value="登录" class="login" style="cursor:poin">
    36. 				</p>
    37. 			</form>
    38. 		</div>
    39. 	</div>
    40. </body>
    41. </html>
    doologin.jsp
    1. <%@ page language="java" import="java.util.*"
    2. 	contentType="text/html; charset=UTF-8"%>
    3. <%
    4. 	String path = request.getContextPath();
    5. 	String basePath = request.getScheme() + "://"
    6. 			+ request.getServerName() + ":" + request.getServerPort()
    7. 			+ path + "/";
    8. 	String username = "";
    9. 	String password = "";
    10. 	request.setCharacterEncoding("utf-8");//防止中文乱码
    11. 	username = request.getParameter("username");
    12. 	password = request.getParameter("password");
    13. 	if ("admin".equals(username) && "admin".equals(password)) {
    14. 		session.setAttribute("loginUser", username);
    15. 		request.getRequestDispatcher("login_success.jsp").forward(
    16. 				request, response);
    17. 	} else {
    18. 		response.sendRedirect("login_failure.jsp");
    19. 	}
    20. %>
    login_success.jsp
    1. <%@ page language="java" import="java.util.*" contentType="text/html; charset=UTF-8"%>
    2. <%
    3. 	String path = request.getContextPath();
    4. 	String basePath = request.getScheme() + "://"
    5. 			+ request.getServerName() + ":" + request.getServerPort()
    6. 			+ path + "/";
    7. %>
    9. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    10. <html>
    11. <head>
    12. <base href="<%=basePath%>">
    14. <title>My JSP 'index.jsp' starting page</title>
    15. <meta http-equiv="pragma" content="no-cache">
    16. <meta http-equiv="cache-control" content="no-cache">
    17. <meta http-equiv="expires" content="0">
    18. <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    19. <meta http-equiv="description" content="This is my page">
    20. <!--
    21. 	<link rel="stylesheet" type="text/css" href="styles.css">
    22. 	-->
    23. </head>
    25. <body>
    26. 	<div id="container">
    27. 		<div></div>
    28. 		<div id="box">
    29. 		<%
    30. 		  String loginUser="";
    31. 		if(session.getAttribute("loginUser")!=null){
    32. 			loginUser=session.getAttribute("loginUser").toString();
    33. 		}
    34. 		%>
    35. 			欢迎你<font color="red"><%=loginUser %></font>，登陆成功
    36. 		</div>
    37. 	</div>
    38. </body>
    39. </html>
    login_failure.jsp
    1. <%@ page language="java" import="java.util.*" contentType="text/html; charset=UTF-8"%>
    2. <%
    3. 	String path = request.getContextPath();
    4. 	String basePath = request.getScheme() + "://"
    5. 			+ request.getServerName() + ":" + request.getServerPort()
    6. 			+ path + "/";
    7. %>
    9. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    10. <html>
    11. <head>
    12. <base href="<%=basePath%>">
    14. <title>My JSP 'index.jsp' starting page</title>
    15. <meta http-equiv="pragma" content="no-cache">
    16. <meta http-equiv="cache-control" content="no-cache">
    17. <meta http-equiv="expires" content="0">
    18. <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    19. <meta http-equiv="description" content="This is my page">
    20. <!--
    21. 	<link rel="stylesheet" type="text/css" href="styles.css">
    22. 	-->
    23. </head>
    25. <body>
    26. 	<div id="container">
    27. 		<div></div>
    28. 		<div id="box">
    29. 			登陆失败；
    30. 			<a href="index.jsp">返回</a>
    31. 		</div>
    32. 	</div>
    33. </body>
    34. </html>
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  • 原文地址：https://www.cnblogs.com/liuruimiku/p/5405315.html
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