Java NIO关于文件读写、拷贝、删除操作备忘

import java.io.IOException;
import java.nio.channels.FileChannel;
import java.nio.charset.Charset;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.StandardCopyOption;
import java.nio.file.StandardOpenOption;
import java.nio.file.attribute.BasicFileAttributes;
import java.nio.file.attribute.FileTime;
import java.time.Instant;

public class NioRelateApiTest {
    public static void main(String[] args) throws IOException {
//        testCopyFileByFileChannel();
//        testCopyFileByFiles();
//        testDelete(getFilePath("temp"));
//        testWite();
//          testRead();
    }

    static void testWrite() throws IOException {
        String text = "hello world";
        Files.write(getFilePath("abc.txt"),text.getBytes(),StandardOpenOption.APPEND);
    }

    static void testRead() throws IOException {
        System.out.println(new String(Files.readAllBytes(getFilePath("abc.txt")), Charset.forName("utf-8")));
    }

    static void testDelete(Path path) throws IOException {
        if(Files.isDirectory(path)){
            Files.walkFileTree(path,new SimpleFileVisitor(){
                @Override
                public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
                    Files.delete(file);
                    return FileVisitResult.CONTINUE;
                }

                @Override
                public FileVisitResult postVisitDirectory(Path dir, IOException exc)
                        throws IOException
                {
                    // 如果不排除根目录，会报DirectoryNotEmptyException异常                    
                    if(!dir.equals(path)){
                        Files.delete(dir);
                    }
                    return FileVisitResult.CONTINUE;
                }
            });
            // 根目录最后删除
            Files.delete(path);
        }else{
            Files.deleteIfExists(path);
        }
    }

    static void testCopyFileByFiles(){
        try {
            Files.copy(getFilePath("abc.txt"),getFilePath("efg.txt"), StandardCopyOption.REPLACE_EXISTING);
            Files.setLastModifiedTime(getFilePath("efg.txt"), FileTime.from(Instant.now()));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    static void testCopyFileByFileChannel(){
        try (
                FileChannel srcChannel = FileChannel.open(getFilePath("abc.txt"), StandardOpenOption.READ);
                FileChannel targetChannel = FileChannel.open( getFilePath("efg.txt"), StandardOpenOption.TRUNCATE_EXISTING,StandardOpenOption.WRITE);
        ) {
            srcChannel.transferTo(0, srcChannel.size(),targetChannel);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    static Path getFilePath(String fileName){
        return Paths.get(fileName);
    }
}