关于JSP的一点疑问小结

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我是靠谱客的博主强健高山，最近开发中收集的这篇文章主要介绍关于JSP的一点疑问小结，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

希望谁能帮我看一看问题出在哪?谢谢!
register.html部分:

复制代码代码如下:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 
<html> 
<head> 
<title>register.html</title> 
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 
<meta http-equiv="description" content="this is my page"> 
<meta http-equiv="content-type" content="text/html; charset=UTF-8"> 
<!--<link rel="stylesheet" type="text/css" href="./styles.css">--> 
</head> 
<body> 
<br> 
<form action="register.jsp" method = "Post" name = "frm"> 
用户名:<input type = "text" name = "in_username"><br> 
密码:<input type = "password" name = "in_password"><br> 
<input type = "submit" name = "submit" value = "提交"> 
</form> 
</body> 
</html> 

复制代码代码如下:

<%@ page language="java" import = java.util.* pageEncoding="ISO-8859-1"%> 
<% 
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 'register.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"> 
<meta http-equiv = "content-type" content = "text/html;charset = gb2312"> 
<!-- 
<link rel="stylesheet" type="text/css" href="styles.css"> 
--> 
</head> 
<body> 
<br> 
<%! boolean isnotlogin = false;%> 
<% 
String username = request.getParameter("username"); 
String password = request.getParameter("password"); 
if(username == null || password == null) 
{ 
response.sendRedirect("error.jsp"); 
return; 
} 
%> 
<jsp:useBean id="person" scope = "page" class = "mypack.register"> 
<jsp:setProperty name = "person" property = "username" param = "username"/> 
<jsp:setProperty name = "person" property = "pwd" param = "password"/> 
</jsp:useBean> 
<% 
isnotlogin = person.judge(); 
if(!isnotlogin) 
{ 
response.sendRedirect("error.jsp"); 
return; 
} 
else 
{ 
session.setAttribute("username", request.getParameter("username")); 
%> 
<jsp:forward page = "sbmt"> 
<jsp:param name = "username" value = "<%=username%>"/> 
</jsp:forward> 
<% 
} 
%> 
</body> 
</html> 

复制代码代码如下:

package mypack; 
public class register { 
private String username = ""; 
private String pwd = ""; 
public void setUserName(String nm) 
{ 
this.username = nm; 
} 
public String getUserName() 
{ 
return this.username; 
} 
public void setPwd(String pd) 
{ 
this.pwd = pd; 
} 
public String getPwd() 
{ 
return this.pwd; 
} 
public boolean judge() 
{ 
boolean temp = false; 
if(username.equals("teacher") && pwd.equals("teacher")) 
{ 
temp = true; 
} 
return temp; 
} 
} 
sbmt.java(Servlet)部分: 
package mypack; 
import java.io.IOException; 
import java.io.PrintWriter; 
import javax.servlet.ServletException; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import javax.servlet.http.HttpSession; 
public class sbmt extends HttpServlet { 
private static final long serialVersionUID = 1L; 
public sbmt() { 
super(); 
} 
public void destroy() { 
super.destroy(); 
} 
public void doGet(HttpServletRequest request, HttpServletResponse response) 
throws ServletException, IOException { 
response.setContentType("text/html"); 
PrintWriter out = response.getWriter(); 
out 
.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">"); 
out.println("<HTML>"); 
out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>"); 
out.println(" <BODY>"); 
out.print(" This is "); 
out.print(this.getClass()); 
out.println(", using the GET method"); 
out.println(" </BODY>"); 
out.println("</HTML>"); 
out.flush(); 
out.close(); 
} 
public void doPost(HttpServletRequest request, HttpServletResponse response) 
throws ServletException, IOException { 
HttpSession session = request.getSession(false); 
if(session == null) 
{ 
response.sendRedirect("error.jsp"); 
return; 
} 
String usernameone = (String)session.getAttribute("username"); 
String usernametwo = request.getParameter("username"); 
if(!usernameone.equals(usernametwo)) 
{ 
response.sendRedirect("error.jsp"); 
return; 
} 
response.setContentType("text/html;charset = GBK"); 
request.setAttribute("username", usernametwo); 
if(usernametwo.equals("teacher")) 
{ 
response.sendRedirect("teacher.jsp"); 
return; 
} 
else 
{ 
response.sendRedirect("error.jsp"); 
return; 
} 
} 
} 
} 