以用户名注册为例分析三种Action获取数据的方式

public String userName;
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
@Override
public String execute() throws Exception {
// TODO Auto-generated method stub

User user = new User();
user.setUserName(userName);//在这里需要将username接收到并且去使用。
UserDAO dao = new UserDAO();
HttpServletResponse response= ServletActionContext.getResponse();
PrintWriter out = response.getWriter();
if(dao.checkExists(user))
{
out.print("");
}
else
{
out.print("");
}
return null;
}

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;
}
@Override
public String execute() throws Exception {
// TODO Auto-generated method stub
UserDAO dao = new UserDAO();
HttpServletResponse response= ServletActionContext.getResponse();
PrintWriter out = response.getWriter();
if(dao.checkExists(user))
{
out.print("");
}
else
{
out.print("");
}
return null;
}
@Override
public User getModel() {
// TODO Auto-generated method stub
return user;
}