NIO.2的文件系统I/O

Files：轻松复制、移动、删除或处理文件的工具类，有你需要的所有方法

public class FilesDemo {
    public static void main(String[] args) throws IOException {
        Path path = Paths.get("D:/work/zk/opensource/javase/ThinkingInJava/bak.txt");
        //Path file = Files.createFile(path);
        //System.out.println(file);
        Files.delete(path);
    }
    public static void copy() throws IOException {
        Path source = Paths.get("D:/work/zk/opensource/javase/ThinkingInJava/bak.txt");
        Path target = Paths.get("D:/demo.txt");
        //copy 可以设置选项  move方法类似
        Files.copy(source,target);
    }
    public static void read(){
        Path file = Paths.get("D:/work/zk/opensource/javase/ThinkingInJava/bak.txt");
        try(BufferedReader reader = Files.newBufferedReader(file, StandardCharsets.UTF_8)){
            String line;
            while ((line = reader.readLine())!=null){
                System.out.println(line);
            }
        }catch (IOException e){
        }
    }
      public static void write(){
        Path file = Paths.get("D:/work/zk/opensource/javase/ThinkingInJava/bak.txt");
        try(BufferedWriter writer = Files.newBufferedWriter(file, StandardCharsets.UTF_8, StandardOpenOption.WRITE)){
            //从头写
            //writer.write("hello world");
            writer.append("hello world");
        }catch (IOException e){
        }
    }
    //简化读写
     public static void simpleRead() throws IOException{
        Path file = Paths.get("D:/work/zk/opensource/javase/ThinkingInJava/bak.txt");
        List<String> allLines = Files.readAllLines(file, StandardCharsets.UTF_8);
        for (String line : allLines) {
            System.out.println(line);
        }
    }
    public static void simpleRead2() throws IOException{
        Path file = Paths.get("D:/work/zk/opensource/javase/ThinkingInJava/bak.txt");
        byte[] bytes = Files.readAllBytes(file);
        System.out.println(new String(bytes));
    }
}

WatchService：用来监视文件或目录的核心类，不管它们有没有变化

import java.io.IOException;
import java.nio.file.*;
import static java.nio.file.StandardWatchEventKinds.*;
public class WatchServiceDemo {
    private static boolean shutdown = false;
    public static void main(String[] args) {
        try {
            WatchService watcher = FileSystems.getDefault().newWatchService();
            //监听D盘根目录
            Path dir = FileSystems.getDefault().getPath("D:/");
            WatchKey key = dir.register(watcher, ENTRY_CREATE,ENTRY_DELETE);
            while (!shutdown) {
                key = watcher.take();
                for (WatchEvent<?> event : key.pollEvents()) {
                    //如果有修改 则发出通知
                    if (event.kind() == ENTRY_CREATE) {
                        System.out.println("有文件创建");
                    }
                    if (event.kind() == ENTRY_DELETE) {
                        System.out.println("有文件删除");
                    }
                }
                key.reset();
            }
        } catch (IOException | InterruptedException e) {
            System.out.println(e.getMessage());
        }
    }
}