Java学习之包

1 package mypack; //包
2 classPackageDemo
3 {
4     public static voidmain(String[] args)
5 {
6         System.out.println("Hello Package!");
7 }
8 }

1 package mypack; //包
2 classPackageDemo
3 {
4     public static voidmain(String[] args)
5 {
6         packa.DemoA d=newpacka.DemoA();
7 d.show();
8         System.out.println("Hello Package!");
9 }
10 }

1 packagepacka;
2 
3 //被访问的包中的类访问权限必须是public
4 public classDemoA
5 {
6     //被访问的包中的类的方法访问权限必须是public
7     public voidshow()
8 {
9         System.out.println("DemoA Show run");
10 }
11 }

1 package mypack; //包
2 
3 import packb.DemoB;//导入了packb包中的DemoB类
4 classPackageDemo
5 {
6     public static voidmain(String[] args)
7 {
8         //1.访问不同包中的类，需要写类的全名称
9         packa.DemoA d=newpacka.DemoA();
10 d.show();
11         DemoB b=newDemoB();
12 b.show();
13         System.out.println("Hello Package!");
14 }
15 }

1 packagepackb;
2 
3 public classDemoB
4 {
5     public voidshow()
6 {
7         System.out.println("DemoB Show run");
8 }
9 }

1 packagejarpack;
2 classJarPackDemo
3 {
4     public static voidmain(String[] args)
5 {
6         System.out.println("Hello Jar Package!");
7 }
8 }