1. Inject properties
Inject properties directly:
public String userName;public String getUserName() {return userName;}public void setUserName(String userName) {this.userName = userName;}@Overridepublic String execute() throws Exception {// TODO Auto-generated method stubUser user = new User();user.setUserName(userName);// Here you need to receive and use the username. UserDAO dao = new UserDAO();HttpServletResponse response= ServletActionContext.getResponse();PrintWriter out = response.getWriter();if(dao.checkExists(user)){out.print("");}else{out.print("");}return null;}2.Domain Model This is a commonly used method
I won't repeat the explanation here.
3.ModelDriven
The third method is not commonly used, you only need to understand;
The process is divided into 4 steps:
(1) Action implements ModelDriven<User> interface
(2) Add abstract methods
(3) Define and initialize a model
User user=new User();
(4) Generate setters and getters
public class CheckUserAction extends ActionSupport implements ModelDriven<User>{private User user = new User();public User getUser() {return user;}public void setUser(User user) {this.user = user;}@Overridepublic String execute() throws Exception {// TODO Auto-generated method stubUserDAO dao = new UserDAO();HttpServletResponse response= ServletActionContext.getResponse();PrintWriter out = response.getWriter();if(dao.checkExists(user)){out.print("");}else{out.print("");}return null;}@Overridepublic User getModel() {// TODO Auto-generated method stubreturn user;}Note: When using methods 1 and 3, there is no need to change the front-end and jsp code parts, because it is the userName attribute that is called directly.
Method 2 requires changing the username in jquery to user.username.