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，
 
 





posted @ 2016-05-04 11:23  半夏来福  阅读(239)  评论(0)    收藏  举报