package-info.java文件

 
@PackageAnotation(version="1.0")

package com.ltao.package.test

class PackageInfo {

    public void common() {

        System.out.println("sa");

    }

}

class PackageInfoGeneric<T extends Throwable> {

    private T obj;

    public void set(T obj) {

        this.obj = obj;

    }

    public void common() {

        System.out.println(obj + "sa");

    }

}

interface packageInfoInteger {

    public void test();

}

class PackageConstants {

    public static final String ERROE_CODE = "100001";

}

PackageAnotation.java 定义修饰包的注解

@Target(ElementType.PACKAGE)

@Retention(RetentionPolicy.RUNTIME)

@interface PackageAnotation
{
    public String version() default "";
}

package com.lt.package.test;  

import java.io.IOException;  

/**

 * 测试package-info.java文件的作用

 * 1、为标注在包上Annotation提供便利；<br>

 * 2、声明包的私有类和常量；<br>

 * @author JoyoungZhang@gmail.com

 *

 */

public class TestPackageInfo {  

    public static void main(String[] args) {

        //1

        Package p = Package.getPackage("com.lt.package.test");

        if(p != null && p.isAnnotationPresent(PackageAnotation.class)){

            PackageAnotation nav = p.getAnnotation(PackageAnotation.class);

            if(nav != null){

                System.out.println("package version:" + nav.version());

            }

        }

    }

}