获取得到项目的根路径

javaSE项目：

URL helloWorld = Thread.currentThread().getContextClassLoader().getResource("com/guang/hello/HelloWorld.class");
System.out.println(helloWorld);

对应输出：

file:/D:/liguang/project/helloworld-java/out/production/helloworld-java/com/guang/hello/HelloWorld.class

javaweb项目：

URL resource1 = Thread.currentThread().getContextClassLoader().getResource("");
 URL resource2 = Thread.currentThread().getContextClassLoader().getResource("com/guang/servlet/HelloServlet.class");
System.out.println("对应的路径是1："+resource1);
System.out.println("对应的路径是2："+resource2);

输出信息：

对应的路径是1file:/D:/liguang/project/helloworld-java/out/artifacts/testtomcat_war_exploded/WEB-INF/classes/
对应的路径是2file:/D:/liguang/project/helloworld-java/out/artifacts/testtomcat_war_exploded/WEB-INF/classes/com/guang/servlet/HelloServlet.class

非常nice