A concise introduction to the use of Java "package"

A concise introduction to the use of Java "package" 1. The establishment of "package"

packages correspond to folders, for example, the package Yanwu corresponds to a folder Yanwu.

The package Yanwu in the program Wuhan.java is required Wuhan.java or WUHAN.CALSS should be placed in the folder Yanwu.

//文件名：wuhan.javapackage yanwu;public class wuhan{    public void pnt()     {        System.out.println("武汉理工大学\n");    }}

Put the above file Wuhan.java into the folder Yanwu, set up the package Yanwu, this package has class Wuhan.

2. Application of "package"

Like a schoolbag, the package Yanwu can be placed anywhere, for example, it can be placed in the C:\dosh folder, that is, the shape of C:\dosh\yaanwu\wuhan.java.
In order to use the class Wuhan in package Yanwu, the following two points must be done:
(1) The location of the package Yanwu, add the system variable classpath, that is, increase the C:\dosh; Indicates the search path of the package.
(2) To use class Wuhan in Package Yanwu, class Wuhan should be introduced in the program. such as import yanwu.*;

The reference routines are as follows:

//文件名：MyClass108.javaimport yanwu.*;class MyClass108{    public static void main(String[] args)     {        wuhan nn=new wuhan();  //建立wuhan类对象        nn.pnt();        System.out.println("Hello World!");    }}

A concise introduction to the use of Java "package"