观察者模式及java实现

function User() {
var name = 'username';
var password = 'password';
//持有对象的this用于内部方法间调用
var $this = User.prototype;
$this.setName = function(_name) {
name = _name;
};
$this.getName = function() {
return name;
};
$this.setPassword = function(_password) {
password = _password;
};
$this.getPassword = function() {
return password;
};
$this.getUser = function() {
alert($this.getName() + $this.getPassword());
};
}
var user = new User();
user.getUser();