其它常用类

1. System类

    @Test
    public void test1() {
        String javaVersion = System.getProperty("java.version");
        System.out.println("java的version:" + javaVersion);

        String javaHome = System.getProperty("java.home");
        System.out.println("java的home:" + javaHome);

        String osName = System.getProperty("os.name");
        System.out.println("os的name:" + osName);

        String osVersion = System.getProperty("os.version");
        System.out.println("os的version:" + osVersion);

        String userName = System.getProperty("user.name");
        System.out.println("user的name:" + userName);

        String userHome = System.getProperty("user.home");
        System.out.println("user的home:" + userHome);

        String userDir = System.getProperty("user.dir");
        System.out.println("user的dir:" + userDir);

    }

2. Math类

2.1 常用方法