你的意思是只想打开一个A窗口吧,不重复打开多个,这个就是java中的单例模式,把class A设置成单例就好了
public class A {
private static A instance;
private A() { }
public static A getInstance() {
if (instance == null) {
synchronized (A .class) {
if (instance == null) {
instance = new A ();
}
}
}
return instance;
}
}
public class B {
public static void main(String[] args) {
A obj = A.getInstance();
obj.a();
}
}