【原】program arguments，vm arguments，environment variable

作者：david_zhang@sh 【转载时请以超链接形式标明文章】

https://www.cnblogs.com/david-zhang-index/p/16846493.html

参数太多，傻傻分不清楚，简单说

1，program arguments是main函数args[]参数

2，vm arguments是java环境变量

3，environment variable是jvm环境变量

看代码如何获取这些参数：

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public class TestProgram {     public static void main(String[] args) {         // program arguments对应的args参数         for (String arg : args) {             System.out.println(arg);         }         System.out.println("==============program arguments对应的args参数===============");         System.out.println();           // getProperty()获取java的环境变量         String value1 = System.getProperty("key1");         String value2 = System.getProperty("key2");         System.out.println("System.getProperty(\"key1\")----->" + value1);         System.out.println("System.getProperty(\"key2\")----->" + value2);         Properties properties = System.getProperties();         System.out.println("System.getProperties():=======>" + properties);         System.out.println("==============getProperty()获取java的环境变量===============");         System.out.println();             // 获取运行jvm环境变量         System.getenv();         Map<String, String> getenv = System.getenv();         System.out.println("System.getenv():----->" + getenv);         String env1 = System.getenv("env1");         String env2 = System.getenv("env2");         System.out.println("System.getenv(\"env1\")=======>" + env1);         System.out.println("System.getenv(\"env2\")=======>" + env2);         System.out.println("===============获取运行jvm环境变量===============");         System.out.println();     } }

-argu=111
-arge=222
==============program arguments对应的args参数===============

System.getProperty("key1")----->v1
System.getProperty("key2")----->v2

==============getProperty()获取java的环境变量===============

System.getenv("env1")=======>test
System.getenv("env2")=======>prod
==============获取运行jvm环境变量===============

参数设置

 总结：

System.getProperty();

System.getProperties();

System.getenv();