I have recently started working with JSPs in Spring framework and I tried implementing a form handling page.
I created a basic form page that takes user input and after they hit submit they receive a confirmation page with the input that they entered.
These are the two mapped methods I have in my controller class:
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import com.redcup.model.Person;
import com.redcup.model.User;
import com.redcup.test.ServletTestBean;
import javax.annotation.PostConstruct;
@Controller
public class RedCupController {
private final Logger logger = LoggerFactory.getLogger(RedCupController.class);
@PostConstruct
public void intializeComplete() {
logger.info("Controller initialized");
}
@RequestMapping(method=RequestMethod.GET, value="/health")
@ResponseBody
public String getHealth()
{
logger.info("GET /health invoked.");
return "hello world!";
}
@RequestMapping(method=RequestMethod.GET, value="/welcome")
public String getWelcome(Model model) {
User user = new User();
model.addAttribute("userform", user);
return "welcome";
}
@RequestMapping(method=RequestMethod.POST, value="/confirmation")
public String getConfirmation(@ModelAttribute("userform") User user, @ModelAttribute("pew") User user2,
@ModelAttribute("whomp")Person person, Model model) {
user = getUserForm();
user2 = getUserForm2();
System.out.println("hello: " + user);
System.out.println("goodbye: " + user2);
System.out.println("user: " + user.getFirstName());
System.out.println("user: " + user.getLastName());
System.out.println("user: " + user.getEmail());
System.out.println("user: " + user.getAge());
System.out.println("user2: " + user2.getFirstName());
System.out.println("user2: " + user2.getLastName());
System.out.println("user2: " + user2.getEmail());
System.out.println("user2: " + user2.getAge());
System.out.println("person: " + person.getName());
System.out.println("person: " + person.getNum2());
model.addAttribute("user", user);
model.addAttribute("user2", user2);
model.addAttribute("person", person);
return "confirmation";
}
@ModelAttribute("userform")
public User getUserForm() {
return new User();
}
@ModelAttribute("userform2")
public User getUserForm2() {
return new User();
}
}
The User class for the model:
public class User {
private String firstName;
private String lastName;
private String email;
private int age;
public User() {
firstName = "John";
lastName = "Smith";
email = "default email";
age = 1;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getFirstName () {
return firstName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getLastName() {
return lastName;
}
public void setEmail(String email) {
this.email = email;
}
public String getEmail() {
return email;
}
public void setAge (int age) {
this.age = age;
}
public int getAge() {
return age;
}
}
And below is the form entry page welcome.jsp:
<!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>Insert title here</title>
</head>
<body>
<div align="center">
<form:form action="confirmation" method="post" commandName="userform">
<form:input path="firstName"/>
<form:input path="lastName"/>
<form:input path="email"/>
<form:input path="age"/>
<input type="submit" value="Press this to submit"/>
</form:form>
</div>
</body>
</html>
In my controller handler: getConfirmation I have two User parameters (user and user2).The part I am confused about is that when I click submit in my welcome.jsp, user and user2 are populated with the same exact values from the Model in the welcome.jsp. I'm not sure why this happens as I thought that the @ModelAttribute will only assign the corresponding model attribute to the specified parameter (i.e. user will receive the model under the commandName userform).
But to me, it doesn't seem like the @ModelAttribute annotation is doing anything. The user and user2 parameters will be populated with the same field values (what I entered into the form) when the @ModelAttributes have different keys (i.e. userform vs userform2) and when I even remove the @ModelAttribute annotations, user and user2 will STILL be popoulated with the same field values.
Can someone explain to why this is occurring and what exactly the @ModelAttribute annotation does?
Thanks in advance!
EDIT
I have created a UserWrapper class per Alan's Hay's suggestion:
public class UserWrapper {
private User user1;
private User user2;
public User getUser1() {
return user1;
}
public User getUser2() {
return user2;
}
public void setUser1(User user) {
user1 = user;
}
public void setUser2(User user) {
user2 = user;
}
public void setUser1FirstName(String firstName) {
user1.setFirstName(firstName);
}
public String getUser1FirstName() {
return user1.getFirstName();
}
public void setUser2FirstName(String firstName) {
user2.setFirstName(firstName);
}
public String getUser2FirstName() {
return user2.getFirstName();
}
}
and updated my welcome.jsp with the following form:
<form:form action="confirmation" method="post" commandName="userform">
<form:input path="user1.firstName"/>
<form:input path="user1.lastName"/>
<form:input path="user1.email"/>
<form:input path="user1.age"/>
<input type="submit" value="Press this to submit"/>
</form:form>
