File

import java.io.File;
public class Main {
    public static void main(String[] args) {
        File f = new File("demo05/src/test.txt");
        System.out.println(f);
        System.out.println(f.getAbsolutePath());
        System.out.println(f.getPath());
        System.out.println(f.isFile());
        System.out.println(f.isDirectory());
        System.out.println(f.canRead());
    }
}

// 创建临时文件
public class Main {
    public static void main(String[] args) throws IOException {
        File f = File.createTempFile("tmp-", ".txt"); // 提供临时文件的前缀和后缀
        f.deleteOnExit(); // JVM退出时自动删除
        System.out.println(f.isFile());
        System.out.println(f.getAbsolutePath());
    }

import java.io.File;
import java.io.FilenameFilter;
public class GetFileDir {
    public static void main(String[] args) {
        File f = new File("C:\\Windows");
        File[] fs1 = f.listFiles();// 列出所有的文件和子目录
        printFiles(fs1);
        File[] fs2 = f.listFiles(new FilenameFilter() {
            @Override
            public boolean accept(File dir, String name) {
                return name.endsWith(".exe");//返回True表示接受该文件
            }
        });
        printFiles(fs2);
    }
    private static void printFiles(File[] files) {
        System.out.println("==========================================");
        if (files != null) {
            for (File f : files) {
                System.out.println(f);
            }
        }
        System.out.println("==========================================");
    }
}

// path路径
import java.io.File;
import java.nio.file.Path;
import java.nio.file.Paths;
public class PathTs {
    public static void main(String[] args) {
        // 构造一个Path对象
        Path p1 = Paths.get(".", "project", "study");
        System.out.println(p1);
        //转化为绝对路径
        Path p2 = p1.toAbsolutePath();
        System.out.println(p2);
        //转换为规范路径
        Path p3 = p2.normalize();
        System.out.println(p3);
        //转换为File对象
        File f = p3.toFile();
        System.out.println(f);
        for (Path p : Paths.get("..").toAbsolutePath()) {
            System.out.println(" " + p);
        }
    }
}