jsp学习

来源：互联网发布：口腔耗材淘宝哪家好编辑：程序博客网时间：2024/06/05 00:47

javabeans及其作用域范围

http://blog.csdn.net/u014038534/article/details/50537065

 <h1>系统登录</h1>    <hr>    <form name="loginForm" action="dologin.jsp?mypass=999999" method="post">      <table >        <tr>          <td>用户名：</td>          <td><input type="text" name="username" value=""/></td>        </tr>        <tr>          <td>密码：</td>          <td><input type="password" name="password" value=""/></td>        </tr>        <tr>          <td colspan="2" align="center"><input type="submit" value="登录"/></td>                  </tr>      </table>    </form>

dologin.jsp:

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'dologin.jsp' starting page</title>    <meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">-->  </head>    <body>    <jsp:useBean id="myUsers" class="com.po.Users" scope="page"/>    <h1>setProperty动作元素</h1>    <hr>   <!--根据表单自动匹配所有的属性 -->   <%--    <jsp:setProperty name="myUsers" property="*"/>     --%>   <!--根据表单匹配所有部分的属性 -->   <%--    <jsp:setProperty name="myUsers" property="username"/>     --%>   <!--根表单无关，通过手工赋值给属性 -->   <%--    <jsp:setProperty name="myUsers" property="username" value="lisi"/>   <jsp:setProperty name="myUsers" property="password" value="888888"/>   --%>   <!--通过URL传参数给属性赋值 -->   <jsp:setProperty name="myUsers" property="username"/>   <jsp:setProperty name="myUsers" property="password" param="mypass"/>   <!-- 使用传统的表达式方式来获取用户名和密码 -->   <%--            用户名：<%=myUsers.getUsername() %><br>       密码：<%=myUsers.getPassword() %><br>    --%>   <!-- 使用getProperty方式来获取用户名和密码 -->      用户名：<jsp:getProperty name="myUsers" property="username"/> <br>      密码：<jsp:getProperty name="myUsers" property="password"/><br>   <br>   <br>      <a href="testScope.jsp">测试javabean的四个作用域范围</a>      <%          request.getRequestDispatcher("testScope.jsp").forward(request, response);      %>  </body></html>

scope_test.jsp:

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%><%@ page import="com.po.Users" %><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'testScope.jsp' starting page</title>    <meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">-->  </head>    <body>    <h1>Javabean的四个作用域范围</h1>    <hr>    <jsp:useBean id="myUsers" class="com.po.Users" scope="page"/>       用户名：<jsp:getProperty name="myUsers" property="username"/><br>       密码：<jsp:getProperty name="myUsers" property="password"/><br>    <!-- 使用内置对象获取用户名和密码 -->    <hr>   <%--        用户名：<%=((Users)application.getAttribute("myUsers")).getUsername()%><br>       密码：<%=((Users)application.getAttribute("myUsers")).getPassword() %><br>   --%>   <%--        用户名：<%=((Users)session.getAttribute("myUsers")).getUsername()%><br>       密码：<%=((Users)session.getAttribute("myUsers")).getPassword() %><br>   --%>   <%--        用户名：<%=((Users)request.getAttribute("myUsers")).getUsername()%><br>       密码：<%=((Users)request.getAttribute("myUsers")).getPassword() %><br>   --%>   <%    //这样做当scope="page"的时候 才不会出现空指针异常 会获得空值       String username = "";       String password = "";       if(pageContext.getAttribute("myUsers")!=null )       {          username = ((Users)pageContext.getAttribute("myUsers")).getUsername();          password = ((Users)pageContext.getAttribute("myUsers")).getPassword();       }          %>           用户名：<%=username%><br>       密码：<%=password%><br>           </body></html>

0 0