struts2中JSP页面给action类赋值的问题

package com.test.action;import com.opensymphony.xwork2.ActionSupport;import com.test.model.User;public class ValideAction extends ActionSupport{/** *  */private static final long serialVersionUID = 1L;private String username;public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}private String password;private User user=new User();/*构造函数中，不会将jsp值赋给action对象*/public ValideAction(){System.out.println(this.getUsername());}/*execute函数中，会将jsp值赋给action对象*/public String execute(){System.out.println(this.getUsername());return SUCCESS;}}

在构造函数中，仍然无法取到对象的值。