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63 javabean的作用域范围

發(fā)布時間：2023/12/10 编程问答 36 豆豆

生活随笔收集整理的這篇文章主要介紹了 63 javabean的作用域范围小編覺得挺不錯的,現(xiàn)在分享給大家,幫大家做個參考.

定義一個users類

package srever;public class Users {private String username;private String password;public Users() {}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}}

定義一個login的jsp頁面

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%><!DOCTYPE html> <html> <head> <meta charset="ISO-8859-1"> <title>Insert title here</title> </head> <body> <h1>用戶登錄</h1> <hr> <form action="dologind.jsp?mypass=999999" name="loginForm" method="post"> <table> <tr> <td>用戶名:</td> <td><input type="text" name="username"/></td> </tr> <tr> <td>密碼:</td> <td><input type="password" name="password"/></td> </tr> <tr> <td colspan="2"><input type="submit" value="登錄"></td> </tr> </table> </body> </html>

定義一個dologind的jsp頁面

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%><!DOCTYPE html> <html> <head> <meta charset="ISO-8859-1"> <title>Insert title here</title> </head> <body> <jsp:useBean id="myUsers" class="srever.Users" scope="application"/> <h1>setproperty</h1><br>  <jsp:setProperty name="myUsers" property="username"/> <jsp:setProperty name="myUsers" property="password" param="mypass"/>  賬號:<jsp:getProperty name="myUsers" property="username"/> 密碼:<jsp:getProperty name="myUsers" property="password" /> <a href="testScope.jsp">測試作用域范圍</a> </body> </html>

定義一個testscope頁面

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> <%@ page import="srever.Users"%> <!DOCTYPE html> <html> <head> <meta charset="ISO-8859-1"> <title>Insert title here</title> </head> <body> <h1>Javabean的作用域</h1> <hr> <jsp:useBean id="myUsers" class="srever.Users" scope="application"/> 賬號:<jsp:getProperty name="myUsers" property="username"/> 密碼:<jsp:getProperty name="myUsers" property="password" />  用戶名:<%=((Users)application.getAttribute("myUsers")).getUsername() %><br> 密碼:<%=((Users)application.getAttribute("myUsers")).getPassword() %><br></body> </html>

運行結(jié)果

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> <%@ page import="srever.Users"%> <!DOCTYPE html> <html> <head> <meta charset="ISO-8859-1"> <title>Insert title here</title> </head> <body> <h1>Javabean的作用域</h1> <hr> <jsp:useBean id="myUsers" class="srever.Users" scope="session"/> 賬號:<jsp:getProperty name="myUsers" property="username"/> 密碼:<jsp:getProperty name="myUsers" property="password" />  <hr> 用戶名:<%=((Users)session.getAttribute("myUsers")).getUsername() %><br> 密碼:<%=((Users)session.getAttribute("myUsers")).getPassword() %><br></body> </html>

改為session

運行結(jié)果

改為request

dologin

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%><!DOCTYPE html> <html> <head> <meta charset="ISO-8859-1"> <title>Insert title here</title> </head> <body> <jsp:useBean id="myUsers" class="srever.Users" scope="application"/> <h1>setproperty</h1><br>  <jsp:setProperty name="myUsers" property="username"/> <jsp:setProperty name="myUsers" property="password" param="mypass"/>  賬號:<jsp:getProperty name="myUsers" property="username"/> 密碼:<jsp:getProperty name="myUsers" property="password" /> <a href="testScope.jsp">測試作用域范圍</a> <%request.getRequestDispatcher("tstScope.jsp").forward(request,response); %> </body> </html>

testscope

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> <%@ page import="srever.Users"%> <!DOCTYPE html> <html> <head> <meta charset="ISO-8859-1"> <title>Insert title here</title> </head> <body> <h1>Javabean的作用域</h1> <hr> <jsp:useBean id="myUsers" class="srever.Users" scope="request"/> 賬號:<jsp:getProperty name="myUsers" property="username"/> 密碼:<jsp:getProperty name="myUsers" property="password" />  <hr> 用戶名:<%=((Users)request.getAttribute("myUsers")).getUsername() %><br> 密碼:<%=((Users)request.getAttribute("myUsers")).getPassword() %><br></body> </html>

可以獲取數(shù)值

page的話只能在當(dāng)前頁面獲得，其他頁面是無效的。

dologin的jsp

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%><!DOCTYPE html> <html> <head> <meta charset="ISO-8859-1"> <title>Insert title here</title> </head> <body> <jsp:useBean id="myUsers" class="srever.Users" scope="page"/> <h1>setproperty</h1><br>  <jsp:setProperty name="myUsers" property="username"/> <jsp:setProperty name="myUsers" property="password" param="mypass"/>  賬號:<jsp:getProperty name="myUsers" property="username"/> 密碼:<jsp:getProperty name="myUsers" property="password" /> <a href="testScope.jsp">測試作用域范圍</a></body> </html>

testscope的jsp

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> <%@ page import="srever.Users"%> <!DOCTYPE html> <html> <head> <meta charset="ISO-8859-1"> <title>Insert title here</title> </head> <body> <h1>Javabean的作用域</h1> <hr> <jsp:useBean id="myUsers" class="srever.Users" scope="request"/> 賬號:<jsp:getProperty name="myUsers" property="username"/> 密碼:<jsp:getProperty name="myUsers" property="password" />  <hr> <%String username="";String password="";if(pageContext.getAttribute("myuser")!=null){username=((Users)pageContext.getAttribute("Users")).getUsername();password=((Users)pageContext.getAttribute("Users")).getPassword();} %> 用戶名:<%=username %> 密碼:<%=password %> </body> </html>

運行結(jié)果

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總結(jié)

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