我正在使用Java servlet和JSP创建一个登录页面.我只是发布了我的doPost方法和validateData方法.我担心的是我想在页面上输出两个以上的错误消息.errorMessageList是负责保存String消息的数组.最初,我试图通过在两个字段中输入数字来输入无效的名字和姓氏.相应的错误消息存储在数组中,但不会显示.仅显示第一个错误消息,即错误:无效的名字.不能为空/包含数字,但下一个错误错误:姓氏无效.即使errorMessageList已经存在,也不能显示空/包含数字.我也提供我的JSP.一些帮助将不胜感激!
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// We are creating all the parameters on the browsers and sending them to the server
String uName = req.getParameter("userName");
String pWord = req.getParameter("password");
String cPass = req.getParameter("confirmPassword");
String fName = req.getParameter("firstName");
String lName = req.getParameter("lastName");
String gender = req.getParameter("gender");
Client client = new Client();
client.setClientName(uName);
client.setPassword(pWord);
client.setConfirmPassword(cPass);
client.setFirstName(fName);
client.setLastName(lName);
client.setGender(gender);
List<String> errorMessageList = validateServlet(client);
boolean isEmpty = errorMessageList.isEmpty();
System.out.println("the errorMessageList is empty:"+isEmpty);
if(errorMessageList.size()==0){//Successful registration
ClientDao clientDao = new ClientDaoImpl();
clientDao.createClient(client);
req.getRequestDispatcher("/WEB-INF/jsp/registrationSuccess.jsp").forward(req, resp);
}
// Error in the submission data. Therefore show registration page.
for(int i = 0; i < errorMessageList.size(); i++){
req.setAttribute("errorMessages", errorMessageList.get(i));
req.getRequestDispatcher("/WEB-INF/jsp/registration.jsp").forward(req, resp);
}
super.doPost(req, resp);
}
public List<String> validateServlet(Client client){
List<String> errorMessages = new ArrayList<String>();
if(client.getClientName() == null || client.getClientName().trim().length() == 0){// Null or Empty
errorMessages.add("Error: Your forgot to type in User Name");
}
if(client.getFirstName() == null || client.getFirstName().trim().length() == 0 || client.getFirstName().matches(NUMBERS_PATTERN)){
errorMessages.add("Error: Invalid First Name. Cannot be empty / contain numbers");
}
if(client.getLastName() == null || client.getLastName().trim().length() == 0 || client.getLastName().matches(NUMBERS_PATTERN)){
errorMessages.add("Error: Invalid Last Name. Cannot be empty / contain numbers");
}else if(!client.getClientName().matches(EMAIL_PATTERN)){
errorMessages.add("Error: Invalid user. User Name should be user@domain.com");
}else if(client.getPassword() == null || client.getPassword().trim().length() == 0){// Null or Empty
errorMessages.add("Error: Your forgot to type in Password");
}else if(client.getConfirmPassword() == null || client.getConfirmPassword().trim().length() == 0){// Null or Empty
errorMessages.add("Error: Your forgot to confirm password");
}else if(!client.getPassword().equals(client.getConfirmPassword())){
errorMessages.add("Error: Password and confirm password do not match..");
}
return errorMessages;
}
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Client Registration Page</title>
</head>
<body style="background-color:#EEFFEE" align="center">
<%
String eMessage = (String)request.getAttribute("errorMessages");
%>
<form action = "/iservlet-webapp/registration" method = "post">
<%if(eMessage != null){ %>
<div style = "color:#CC3300; align:center">
<%=eMessage%>
</div>
<%} %>
<font face="Arial" color="green">User Registration Page</font>
<hr>
<br>
<table align="center" border="1" bordercolor= "green" bgcolor="CCFF99">
<tr>
<td>User Name</td>
<td><input type ="text" name ="userName" maxlength = "50"/></td>
</tr>
<tr>
<td>Password</td>
<td><input type ="password" name ="password" maxlength = "15"/></td>
</tr>
<tr>
<td>Confirm Password</td>
<td><input type ="password" name ="confirmPassword" maxlength = "45"/></td>
</tr>
<tr>
<td>First Name</td>
<td><input type ="text" name ="firstName" maxlength = "45"/></td>
</tr>
<tr>
<td>Last Name</td>
<td><input type ="text" name ="lastName" maxlength = "45"/></td>
</tr>
<tr>
<td>Gender</td>
<td><input type ="text" name ="gender" maxlength = "1"/></td>
</tr>
<tr>
<td colspan="2"><input type = "submit" name ="Login"/></td>
</tr>
</table>
</form>
</body>
</html>
// Error in the submission data. Therefore show registration page.
for(int i = 0; i < errorMessageList.size(); i++){
req.setAttribute("errorMessages", errorMessageList.get(i));
req.getRequestDispatcher("/WEB-INF/jsp/registration.jsp").forward(req, resp);
}
通过上面的代码,你只设置1 error是在0th列表的索引,因为要调用forward()每个迭代法.
相反,您应该添加完整errorList的属性:
req.setAttribute("errorMessages", errorMessageList);
req.getRequestDispatcher("/WEB-INF/jsp/registration.jsp").forward(req, resp);
现在只需在JSP中迭代列表.
更新
如何在JSP中迭代列表？
<c:forEach items="${errorMessages}" var="error">
<h2>${error}</h2>
</c:forEach>
要使用,<c:forEach>您需要jstl.jar在类路径中添加并在jsp中添加以下行.
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
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