java中只有值传递,当一个引用对象当做参数传递时其实传递是对象的拷贝。
代码:
public static void update(int a){
a= 4;
}
public static void updateObject(User user){
user.setUsername("shuiage");
}
public static void main(String[]args){
a = 5;
update(a);
System.out.println(a); ///a=5;
User user = new User("xiaoshuaige","123");
updateObject(user);
System.out.println(user.getUsername()); //等于shuaige;
}
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