static 方法

static 方法就是没有this 的方法,在static 内部不能调用非静态方法,反过来倒是可以,而且可以在没有创建任何其他对象的前提下,仅仅通过类本身调用static 方法,

static 成员初始化顺序

package object;

class Bowl {
    Bowl(int marker)
    {
        System.out.printf("Bowl("+marker+")\n");
    }
    void f1(int marker)
    {
        System.out.printf("f1("+marker+")\n");
    }
}
class Table{
    static Bowl bowl1 =new Bowl(1);
    Table()
    {
        System.out.println("table()");
    }
    void f2(int marker)
    {
        System.out.println("f2("+marker+")");
    }
    static Bowl bowl2 = new Bowl(2);
}
class Cupboard
{
    Bowl  bowl3 = new Bowl(3);
    static Bowl bowl4 = new Bowl(4);
    Cupboard()
    {
        System.out.print("Cupboard\n");
        bowl4.f1(2);
    }
    void f3(int marker)
    {
        System.out.println("f3("+marker+")");
    }
    static Bowl bowl5 = new Bowl(5);
}
public class StaticInitialization{
    public static void main(String args[])
    {
        System.out.println("Creating new Cupboard() in main");
        new Cupboard();  //静态成员只有在第一个Cupboard在创建时才会初始化,此后,静态成员不会再次初始化
        System.out.println("Creating new Cupboard() in main");
        Cupboard cupboard = new Cupboard();
        new Table().f2(1);
        new Cupboard().f3(1);
    }
}/* output:
Creating new Cupboard() in main
Bowl(4)
Bowl(5)
Bowl(3)
Cupboard
f1(2)
Creating new Cupboard() in main
Bowl(3)
Cupboard
f1(2)
Bowl(1)
Bowl(2)
table()
f2(1)
Bowl(3)
Cupboard
f1(2)
f3(1)
*///~

显示的初始化静态方法

package object;
//: initialization/ExplicitStatic.java

import static net.mindview.util.Print.*;

class Cup
{
    Cup(int marker)
    {    
        print("Cup("+ marker +")");
    }
    void f(int marker)
    {
        print("f("+marker+")");
    }
}
class Cups
{
    static Cup cup1;
    static Cup cup2; //静态域
    static{
        cup1 = new Cup(1);
        cup2 = new Cup(2);
    }    //静态块
    Cups()
    {
        print("Cups()");
    }
}

public class ExplicitStatic{
    public static void main(String args[])
    {
        print("Inside main()");
        Cups.cup1.f(99); // (1)     无论时通过(1)还是注释掉(1)运行(2),Cups的静态初始化都会执行
                         // 静态初始化只会执行一次,如果(1)(2)全部注释掉则不会执行初始化

    }
     //static Cups cups1 = new Cups(); //(2)
     //static Cups cups2 = new Cups(); //(2)
}/* output:
Inside main()
Cup(1)
Cup(2)
f(99)
*///~