Java Spring MVC 3 表单验证器未在 .jsp 中显示错误消息
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Spring MVC 3 Form Validator not displaying Error message in .jsp
提问by ramlax
I entered in Spring Web MVC Frameworknot long ago thus I am a complete beginner. Right now I am implementing a basic formfor my first web application.
不久前进入Spring Web MVC 框架，所以我是一个完整的初学者。现在我正在为我的第一个web 应用程序实现一个基本的表单。
In the same time I would like to say that I've been seeking a solution for my problem for whole day. I apolgize in advance if the solution for similar problem was already published.
同时，我想说我一整天都在为我的问题寻求解决方案。如果类似问题的解决方案已经发布，我会提前道歉。
Source code:
源代码：
spring-servlet.xml
spring-servlet.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<context:component-scan base-package="si.src.controllers" />
<context:component-scan base-package="si.src.validators" />
<bean id="viewResolver"
class="org.springframework.web.servlet.view.UrlBasedViewResolver">
<property name="viewClass">
<value>org.springframework.web.servlet.view.JstlView</value>
</property>
<property name="prefix">
<value>/WEB-INF/jsp/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
</beans>
index.jsp
索引.jsp
<!-- language: lang-jsp -->
<html>
<head>
<title>Spring 3.0 MVC Series - Index</title>
</head>
<body>
<br>
<div align='center'>
<p>
<h1>Example - Spring Application</h1>
The "index.jsp" is the entry point for our application.
This is my first test. Work!
<p>
<a href="login.html">Welcome! Click Here to Login</a>
</div>
</body>
</html>
login.jsp
登录.jsp
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<html>
<head>
<title>Spring Sample - Login Page</title>
</head>
<body>
<h3>Login Page</h3><br>
<form:form id="form" method="post" commandName="loginForm">
<form:errors path="*" cssClass="errorblock" element="div" />
<table>
<tr>
<td><form:label path="username">Username</form:label></td>
<td><form:input path="username" /></td>
<td><form:errors path="username" cssClass="error"/></td>
</tr>
<tr>
<td><form:label path="username">Password</form:label></td>
<td><form:input path="password" /></td>
<td><form:errors path="password" cssClass="error"/></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="Sign in" /></td>
</tr>
</table>
</form:form>
</body>
</html>
LoginFormController.java
登录表单控制器.java
package si.src.controllers;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.validation.BindException;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.mvc.SimpleFormController;
import org.springframework.web.servlet.ModelAndView;
import si.src.logic.Login;
import si.src.validators.LoginValidator;
@Controller
@RequestMapping(value="/login")
public class LoginFormController extends SimpleFormController{
public LoginFormController(){
setCommandClass(Login.class); //Form's values will store into the Login object
setCommandName("loginForm"); //If HTML form action value with named "loginForm" is sumbitted, Spring will forward request to this form controller
}
@RequestMapping(method=RequestMethod.POST)
protected ModelAndView onSubmit(HttpServletRequest request,
HttpServletResponse response, Object command, BindException errors) throws Exception{
LoginValidator validator = new LoginValidator();
Login userLogin = (Login) command;
validator.validate(userLogin, errors.getBindingResult());
if(errors.hasErrors()){
userLogin.setUsername("");
userLogin.setPassword("");
System.out.println("Ne");
return new ModelAndView("login","loginForm", userLogin);
}
else{
System.out.println(userLogin);
System.out.println(userLogin.getUsername() + " " + userLogin.getPassword());
return new ModelAndView("success","userLogin", userLogin);
}
}
protected Object formBackingObject(HttpServletRequest request) throws Exception {
//Initialize the values in the form. Not necessary
Login userLogin = new Login();
userLogin.setUsername("Admin");
return userLogin;
}
}
LoginValidator.java
登录验证器.java
package si.src.validators;
import org.springframework.validation.Errors;
import org.springframework.validation.Validator;
import org.springframework.validation.ValidationUtils;
import si.src.logic.Login;
public class LoginValidator implements Validator{
public boolean supports(Class aClass) {
//just validate the Login instances
return Login.class.isAssignableFrom(aClass);
}
public void validate(Object obj, Errors errors) {
Login login = (Login) obj;
ValidationUtils.rejectIfEmptyOrWhitespace(errors, "username","required-username", "Enter username");
ValidationUtils.rejectIfEmptyOrWhitespace(errors, "password","required-password", "Enter password");
}
}
Login.java
登录.java
package si.src.logic;
public class Login {
private String username;
private String password;
public Login(){}
public void setUsername(String username){
this.username=username;
}
public String getUsername(){
return username;
}
public void setPassword(String password){
this.password=password;
}
public String getPassword(){
return password;
}
}
I suppose the error messages obtained by LoginValidatorobject are not correctly "binded" with my login.jspfile. I guess that is the reason why the error messagesi.e "Enter username"and "Enter password"don't show up when my form is poorly fulfilled.
我想LoginValidator对象获得的错误消息没有与我的login.jsp文件正确“绑定” 。我想这就是为什么当我的表单没有得到很好的满足时，错误消息，即“输入用户名”和“输入密码”不显示的原因。
My question is: Why the error messages are not showing up in a login.jsp?
我的问题是：为什么错误消息没有显示在 login.jsp 中？
采纳答案by user2983066
I have similar problem. Also I have changed the type of return, but I have the need to trasfert date from controller to JSP. I use object model, but I have the same result of object modelandview.
我有类似的问题。我也改变了返回的类型，但我需要将日期从控制器传输到 JSP。我使用对象模型，但对象模型和视图的结果相同。
How can I transfer data without losing the display of form:errors?
如何在不丢失表单显示的情况下传输数据：错误？
@RequestMapping(value="/addCaregiver", method= RequestMethod.POST)
public String addCaregiver(@ModelAttribute("caregiver") @Valid
Caregivers caregiver, BindingResult result,Principal principal, Model model){
caregiverValidator.validate(caregiver, result);
if(result.hasErrors()){
model.addAttribute("caregivers",pp.getCaregiverses(principal.getName()));
model.addAttribute("error", "true");
model.addAttribute("caregiver", new Caregivers());
return "caregiver";
}
return "intro";
}
I solved, don't create a new istance, I delete this row:
我解决了，不要创建一个新的实例，我删除了这一行：
model.addAttribute("caregiver", new Caregivers());
回答by M. Deinum
return new ModelAndView("login","loginForm", userLogin);
You are destroying the model yourself. You are constructing a ModelAndViewyourself with a new model, ignoring/abandoning the current model. As such that also destroys the binding errors.
您自己正在破坏模型。您正在ModelAndView使用新模型构建自己，忽略/放弃当前模型。因此，这也会破坏绑定错误。
Also your code is wrong, you are extending a SimpleFormControllerwhich is a Controllerand annotating it with @Controller. This is trouble waiting to happen, remove the extends SimpleFormControlleras that is deprecated.
此外，您的代码是错误的，您正在扩展SimpleFormControlleraController并用@Controller. 这是等待发生的麻烦，删除extends SimpleFormController已弃用的。
Change your controller to something like this
将您的控制器更改为这样的
@Controller
@RequestMapping(value="/login")
public class LoginFormController {
@ModelAttribute("loginForm")
public Login loginForm() {
return new Login();
userLogin.setUsername("Admin");
return userLogin;
}
@RequestMapping(method=RequestMethod.POST)
public String submit(@ModelAttribute Login loginForm, BindingResult model) {
LoginValidator validator = new LoginValidator();
validator.validate(loginForm, model);
if(errors.hasErrors()){
loginForm.setUsername("");
loginForm.setPassword("");
System.out.println("Ne");
return "login";
} else{
System.out.println(loginForm);
System.out.println(loginForm.getUsername() + " " + loginForm.getPassword());
return "success";
}
}
}
