java 对于java.nio.file.Files

Posted 2021-05-08

import org.junit.Test;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.Charset;
import java.nio.file.FileVisitOption;
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.util.EnumSet;
import java.util.List;

/**
 * @author piumnl
 * @version 1.0.0
 * @since on 2016-12-29.
 */
public class FilesDemo {

  @Test
  public void test_readAllBytes() throws IOException {
    byte[] bytes = Files.readAllBytes(Paths.get("E:", "xuan.png"));
    Path png = Paths.get("E:", "m.png" );
    Files.deleteIfExists(png);
    Files.write(png, bytes, StandardOpenOption.CREATE_NEW);
  }

  @Test
  public void test_readAllLines() throws IOException {
    String userDir = System.getProperty("user.dir");
    Path imlFile = Paths.get(userDir, "io.iml");
    List<String> strings = Files.readAllLines(imlFile, Charset.forName("UTF-8"));
    Path path = Paths.get(userDir, "write.iml");
    if (Files.notExists(path)) {
      Files.createFile(path);
    }
    Files.write(path, strings, Charset.forName("UTF-8"));
  }

  @Test
  public void test_stream() throws IOException {
    Path inPath = Paths.get(System.getProperty("user.dir"), "io.iml");
    Path outPath = Paths.get(System.getProperty("user.dir"), "write.iml");
    InputStream inputStream = Files.newInputStream(inPath, StandardOpenOption.APPEND);
    OutputStream outputStream = Files.newOutputStream(outPath);
    BufferedReader bufferedReader = Files.newBufferedReader(inPath, Charset.forName("UTF-8"));
    BufferedWriter bufferedWriter = Files.newBufferedWriter(outPath, Charset.forName("UTF-8"));
  }

  @Test
  public void test_copy() throws IOException {
    Files.copy(Paths.get(System.getProperty("user.dir"), "io.iml"),
      Paths.get(System.getProperty("user.dir"), "io_copy.iml"),
      StandardCopyOption.REPLACE_EXISTING);
  }

  @Test
  public void test_move() throws IOException {
    Files.move(Paths.get(System.getProperty("user.dir"), "io_copy.iml"),
      Paths.get(System.getProperty("user.dir"), "mm"));
  }

  @Test
  public void test_delete() throws IOException {
//    Files.delete(Paths.get(System.getProperty("user.dir"), "mm"));
    Files.deleteIfExists(Paths.get(System.getProperty("user.dir"), "mm"));
  }

  @Test
  public void test_createDirectory() throws IOException {
//    Files.createDirectory(Paths.get(System.getProperty("user.dir"), "mm", "xx"));
//    Files.createDirectory(Paths.get(System.getProperty("user.dir"), "mm"));
    Files.createDirectories(Paths.get(System.getProperty("user.dir"), "mm1", "xx"));
  }

  @Test
  public void test_createFile() throws IOException {
    Files.createFile(Paths.get(System.getProperty("user.dir"), "createFile.txt"));
  }

  @Test
  public void test_createTempFile() throws IOException, InterruptedException {
    Path path = Paths.get(System.getProperty("user.dir"), "temp");
    if (Files.notExists(path))
      Files.createDirectory(path);
    Files.createTempFile(path, "log", ".txt");
  }

  @Test
  public void test_createTempDirectory() throws IOException {
    Path tempPath = Paths.get(System.getProperty("user.dir"), "temp");
    if (Files.notExists(tempPath)) {
      Files.createDirectory(tempPath);
    }
    Files.createTempDirectory(tempPath, "xx");
  }


  @Test
  public void test_SymbolLink() throws IOException {
    Path link = Paths.get("E:", "scp", "mmm.link");
    Files.createSymbolicLink(link, Paths.get(System.getProperty("user.dir")));
  }

  @Test
  public void test_walk() throws IOException {
    Path path = Paths.get(System.getProperty("user.dir"));
    ListTree listTree = new ListTree();
    Files.walkFileTree(path, listTree);

    EnumSet<FileVisitOption> followLinks = EnumSet.of(FileVisitOption.FOLLOW_LINKS);
    Files.walkFileTree(path, followLinks, Integer.MAX_VALUE, listTree);
  }

  // NIO2 递归遍历文件目录的接口实现
  class ListTree extends SimpleFileVisitor<Path> {
    @Override
    public FileVisitResult postVisitDirectory(Path dir, IOException exc) {
      System.out.println("Visited directory: " + dir.toString());
      return FileVisitResult.CONTINUE;
    }

    @Override
    public FileVisitResult visitFileFailed(Path file, IOException exc) {
      System.out.println(exc);
      return FileVisitResult.CONTINUE;
    }
  }
}