java基础:maven项目获取resources资源文件

public class ClassResoucePath {

    public static void main(String[] args) throws ClassNotFoundException, IOException {
        //取当前类Class对象的三种方式
        Class<ClassResoucePath> clazz1 = ClassResoucePath.class;
        Class<? extends ClassResoucePath> clazz2 = new ClassResoucePath().getClass();
        Class<ClassResoucePath> clazz3 = (Class<ClassResoucePath>) Class.forName("indepth.study.io.ClassResoucePath");

        //maven 项目在编译时会将resources 目录下的所有资源文件copy到 classpath下
        //因此,通过类加载可以找到指定的资源文件
        URL resource1 = clazz1.getClassLoader().getResource("input.txt");
        System.out.println(resource1.getPath());
        //通过urlpath获取文件
        File rf = new File(resource1.getPath());
        System.out.println(rf.exists());
        //直接返回资源文件数据流
        InputStream resourceAsStream = clazz2.getClassLoader().getResourceAsStream("input.txt");

        //当前系统路径分隔符
        String pathSeparator = File.pathSeparator;
        //当前系统路径名称分隔符
        String separator = File.separator;
        //从要路径下查找文件
        File file = new File(separator+"input.txt");
        String canonicalPath = file.getCanonicalPath();
        System.out.println(file.exists());
        System.out.println(canonicalPath);
        //从根路径下查找文件，项目根目录下
        File file2 = new File("input.txt");
        String canonicalPath2 = file2.getCanonicalPath();
        System.out.println(canonicalPath2);
        System.out.println(file2.exists());

    }
}