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  • jsp3 javabean

     Javabean
    解决的代码重复编写，
    1公有类2无参公有构造方法3属性私有4getter和aetter方法
    JSP动作元素
      为请求阶段体
    1：在JSP页面使用Javabean
    ---new    像普通java类
    Uers.java
    1. package com.po;
    3. public class Users {
    4. 	private String username;// 用户名
    5. 	private String password;// mima
    7. 	public Users() {
    8. 		// 默认构造方法
    9. 	}
    11. 	public String getUsername() {
    12. 		return username;
    13. 	}
    15. 	public void setUsername(String username) {
    16. 		this.username = username;
    17. 	}
    19. 	public String getPassword() {
    20. 		return password;
    21. 	}
    23. 	public void setPassword(String password) {
    24. 		this.password = password;
    25. 	}
    27. }
    .jsp
    1. <%@ page language="java" import="java.util.*" contentType="text/html; charset=UTF-8" %>
    2. <%@page import="com.po.Users" %>
    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 'index.jsp' starting page</title>
    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. 	-->
    22.   </head>
    23.   
    24.   <body>
    25.   <%
    26.     Users user=new Users();
    27.   user.setUsername("admin");
    28.   user.setPassword("123456");
    29.   %>
    30.     <h1>使用普通方式使用Javabean</h1>
    31.      <hr>
    32.      用户名:<%=user.getUsername() %><br>
    33.      密码:<%=user.getPassword() %><br>
    34.   </body>
    35. </html>

    ---使用jsp动作标签使用javabean
    <jsp:useBeans> 在jsp页面实例化或在指定范围使用javabean;
    <jsp:useBen id="标识符" class="java类名"  scope="作用范围"/>
    1. <%@ page language="java" import="java.util.*" contentType="text/html; charset=UTF-8" %>
    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 'index.jsp' starting page</title>
    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. 	-->
    22.   </head>
    23.   
    24.   <body>
    25.   <jsp:useBean id="myUsers" class="com.po.Users" scope="page"/>
    26.     <h1>使用useBean使用Javabean</h1>
    27.      <hr>
    28.      用户名:<%=myUsers.getUsername() %><br>
    29.      密码:<%=myUsers.getPassword() %><br>
    30.   </body>
    31. </html>
    <jsp:setProperty>给已经实例化的javaBean对象属性赋值：4



    login.jsp
    1. <body>
    2. 	<h1>系统登录</h1>
    3. 	<hr>
    4. 	<form name="loginForm" action="dologin.jsp?mypass=999999" methood="post">
    5. 		<table>
    6. 			<tr>
    7. 				<td>用户名</td>
    8. 				<td><input type="text" name="username" value="" /></td>
    9. 			</tr>
    10. 			<tr>
    11. 				<td>密码</td>
    12. 				<td><input type="password" name="password" value="" /></td>
    13. 			</tr>
    14. 			<tr>
    15. 				<td colspan="2" align="center"><input type="submit" value="登录" /></td>
    16. 			</tr>
    17. 		</table>
    18. 	</form>
    19. </body>
    dologin.jsp
    1. <%@ page language="java" import="java.util.*" contentType="text/html; charset=UTF-8" %>
    2. <%@page import="com.po.Users" %>
    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 'index.jsp' starting page</title>
    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. 	-->
    22.   </head>
    23.   
    24.   <body>
    25.    <jsp:useBean id="myUsers" class="com.po.Users" scope="page"/>
    26.     <h1>setProperty动作</h1>
    27.      <hr>
    28.      <!-- 根据表单自动匹配所有的属性 -->
    29.      <%-- <jsp:setProperty name="myUsers" property="*"/> --%>
    30.      <!-- 根据表单匹配部分的属性 -->
    31.      <%-- <jsp:setProperty property="username" name="myUsers"/> --%>
    32.      <!-- 于表单无关，手工赋值属性 -->
    33.      <%-- <jsp:setProperty name="myUsers" property="username" value="ilas"/>
    34.      <jsp:setProperty name="myUsers" property="password" value="12345"/> --%>
    35.      <!-- 通过URL传参数，给属性赋值 -->
    36.      <jsp:setProperty property="username" name="myUsers"/>
    37.      <jsp:setProperty name="myUsers" property="password" param="mypass"/>
    38.             用户名:<%=myUsers.getUsername() %><br> 
    39.             密码:<%=myUsers.getPassword() %><br>
    40.   </body>
    41. </htm l>
    <jsp:getProperty>获取指定javanbean对象属性值
     <jsp:getProperty name="javaBean实例名" property="属性名">
      
    1.       <!-- 使用getProperty来获取用户名和密码 -->    
    2.        用户名：<jsp:getProperty name="myUsers" property="username"/><br>  
    3.           密码：<jsp:getProperty name="myUsers" property="password"/><br>
    javabean作用域
       使用useBean的scope属性，来指定javabean的作用范围
    page//仅在当前页面有效
    request//通过HtttpRequest.getAttribute()
    session//通过HttpSession.getAttribute()
    applicatoin//通过applicatoin.getAttribute()---可以作用 整个WEB应用

    1.  <h1>JAVAbean的四个作用范围</h1><hr>
    2.     <jsp:useBean id="myUsers" class="com.po.Users" scope="page"/><!-- page applicatio session request -->
    3.        用户名：<jsp:getProperty name="myUsers" property="username"/><br>  
    4.           密码：<jsp:getProperty name="myUsers" property="password"/><br>  
    5.            <!-- 使用内置对象获取用户名和密码 -->
    6.          <hr>
    7.          <%--  
    8.             用户名：<%=((Users)application.getAttribute("myUsers")).getUsername() %><br>  
    9.           密码：<%=((Users)application.getAttribute("myUsers")).getPassword() %><br>   --%>
    10.            <hr> 
    11.            <%--  用户名：<%=((Users)session.getAttribute("myUsers")).getUsername() %><br>  
    12.           密码：<%=((Users)session.getAttribute("myUsers")).getPassword() %><br>   --%>
    13.           <hr>
    14.           <%--  用户名：<%=((Users)request.getAttribute("myUsers")).getUsername() %><br>  
    15.           密码：<%=((Users)request.getAttribute("myUsers")).getPassword() %><br>   --%>
    Model1模式
     jsp接受页面，
     
     
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  • 原文地址：https://www.cnblogs.com/liuruimiku/p/5457802.html
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