JAVA原生

一、系统属性的获取：

package org.eclipse.winery.repository;

import java.util.Properties;

public class Main {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Properties properties = System.getProperties();
        String str = properties.toString();
        String[] strplits = str.split(",");
        for (String i : strplits) {
            System.out.println(i);
        }
        System.out.println(System.getProperty("user.dir"));

    }

}

二、本地属性的获取Properties：

package org.eclipse.winery.repository;

import java.util.Properties;

public class Main {

    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub
        Properties properties = new Properties();
        properties.load(Main.class.getResourceAsStream("/config.properties"));
        System.out.println(properties.toString());

    }

}

二、获取本地ip

String ip = Inet4Address.getLocalHost().getHostAddress();

 三、java的类与对象的从属关系的判断：

1、isAssignableFrom  class1.isAssignableFrom(class2)  

    class1是class2的父类或者接口返回true
    class1和class2是同一个接口或者类返回true

2、instance of     (obj instance of class)
   
3、isInstance    (class.isInstance(obj))
   
四、URL与URI