关于相对路径

public class FileTest {
    public static void main(String[] args){
        System.out.println(FileTest.class.getClassLoader().getResource("1.txt").getPath());
        System.out.println(FileTest.class.getClassLoader().getResource("").getPath());
        System.out.println(FileTest.class.getClassLoader().getResource("tools/1.txt").getPath());
    }

}

结果输出如下：/C:/Users/Jane/workspace/StudyProject/bin/1.txt/C:/Users/Jane/workspace/StudyProject/bin/Exception in thread "main" java.lang.NullPointerExceptionat com.example.test.FileTest.main(FileTest.java:9)

1.txt在工程的bin目录下存在时，运行不会报空指针异常。

tools/1.txt是在工程下（非bin目录）新建的文件夹文件</p></div>