jave web项目取路径

System.out.println(Thread.currentThread().getContextClassLoader().getResource("").toURI());
System.out.println(TestIndex.class.getClassLoader().getResource("").toURI());
System.out.println(ClassLoader.getSystemResource(""));
System.out.println(TestIndex.class.getResource(""));
System.out.println(TestIndex.class.getResource("../../"));
System.out.println(new File("/").getAbsolutePath());
System.getProperty("user.dir");