项目中查找文件路径
System.out.println(Thread.currentThread().getContextClassLoader().getResource(""));
//pageContext.getServletContext().getResourceAsStream("xml/book.xml")
System.out.println(XmlProcessor.class.getClassLoader().getResource(""));

System.out.println(ClassLoader.getSystemResource(""));
System.out.println(XmlProcessor.class.getResource(""));
System.out.println(XmlProcessor.class.getResource("/")); //Class文件所在路径
System.out.println(new File("/").getAbsolutePath());
System.out.println(System.getProperty("user.dir"));