You can use username registration to analyze three actions to obtain data, and three actions.

Source: Internet
Author: User

You can use username registration to analyze three actions to obtain data, and three actions.

1. Inject attributes


Directly inject attributes:

1 public String userName; 2 3 4 public String getUserName () {5 return userName; 6} 7 8 9 public void setUserName (String userName) {10 this. userName = userName; 11} 12 13 14 @ Override15 public String execute () throws Exception {16 // TODO Auto-generated method stub17 18 User user = new User (); 19 user. setUserName (userName); // here you need to receive and use username. 20 UserDAO dao = new UserDAO (); 21 HttpServletResponse response = ServletActionContext. getResponse (); 22 PrintWriter out = response. getWriter (); 23 if (dao. checkExists (user) 24 {25 out. print ("1"); 26} 27 else28 {29 out. print ("0"); 30} 31 return null; 32}

 


2. Domain Model this is a common method

This is not repeated here,

3. ModelDriven

The third method is not commonly used. You only need to understand it;

The process is divided into four steps:
(1) Implement the ModelDriven <User> interface for action
(2) Add Abstract METHODS
(3) Define and initialize a model
User user = new User ();
(4) generate setter and getter

 1 public class CheckUserAction extends ActionSupport implements ModelDriven<User>{ 2     private User user = new User(); 3     public User getUser() { 4         return user; 5     } 6  7     public void setUser(User user) { 8         this.user = user; 9     }10 11     @Override12     public String execute() throws Exception {13         // TODO Auto-generated method stub14         15         16         UserDAO dao = new UserDAO();17         HttpServletResponse response= ServletActionContext.getResponse();18         PrintWriter out = response.getWriter();19         if(dao.checkExists(user))20         {21             out.print("1");22         }23         else24         {25             out.print("0");26         }27         return null;28     }29 30     @Override31     public User getModel() {32         // TODO Auto-generated method stub33         return user;34     }35     

Note: you do not need to change the front-end and jsp code when using methods 1 and 3, because the userName attribute is directly called.

Method 2: Change username in jquery to user. username.

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