创建一个java记事本管理器。要求如下: ①从键盘上输入1，在当前目录下创建文件iotest6txt②从键盘上输入2，将E盘iotest2txt复制iotest3txt. ③从键盘上输入3，修改E盘iotest3txt文件的内容为”修改文件3内容“. 4.从键盘上输入4.统计当前目录下文件的个数，并输出每 个文件的文件名，大小，最近修改时间。

好的，以下是一个基本的Java记事本管理器的实现，你可以根据需要进行修改和优化。

import java.io.*;
import java.nio.file.*;
import java.nio.file.attribute.*;
import java.text.SimpleDateFormat;
import java.util.*;

public class MyFileManager {
    public static void main(String[] args) throws IOException {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.println("Please select an operation:");
            System.out.println("1. Create file");
            System.out.println("2. Copy file");
            System.out.println("3. Modify file");
            System.out.println("4. List files");
            System.out.println("5. Quit");
            String choice = scanner.nextLine();
            switch (choice) {
                case "1":
                    createFile();
                    break;
                case "2":
                    copyFile();
                    break;
                case "3":
                    modifyFile();
                    break;
                case "4":
                    listFiles();
                    break;
                case "5":
                    System.exit(0);
                default:
                    System.out.println("Invalid choice. Please try again.");
                    break;
            }
        }
    }

    public static void createFile() throws IOException {
        String filename = "iotest6.txt";
        Path path = Paths.get(filename);
        if (!Files.exists(path)) {
            Files.createFile(path);
            System.out.println("File " + filename + " created successfully!");
        } else {
            System.out.println("File already exists!");
        }
    }

    public static void copyFile() throws IOException {
        Path srcPath = Paths.get("E:/iotest2.txt");
        Path destPath = Paths.get("iotest3.txt");
        if (Files.exists(srcPath)) {
            Files.copy(srcPath, destPath, StandardCopyOption.REPLACE_EXISTING);
            System.out.println(srcPath + " copied to " + destPath + " successfully!");
        } else {
            System.out.println(srcPath + " does not exist!");
        }
    }

    public static void modifyFile() throws IOException {
        String filename = "iotest3.txt";
        Path path = Paths.get(filename);
        if (Files.exists(path)) {
            Files.write(path, "Modified file 3 content.\n".getBytes());
            System.out.println("File " + filename + " modified successfully!");
        } else {
            System.out.println("File does not exist!");
        }
    }

    public static void listFiles() throws IOException {
        DirectoryStream.Filter<Path> filter = new DirectoryStream.Filter<Path>() {
            @Override
            public boolean accept(Path entry) throws IOException {
                return Files.isRegularFile(entry);
            }
        };
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        try (DirectoryStream<Path> stream = Files.newDirectoryStream(Paths.get("."), filter)) {
            for (Path path : stream) {
                BasicFileAttributes attrs = Files.readAttributes(path, BasicFileAttributes.class);
                long size = attrs.size();
                String mtime = sdf.format(new Date(attrs.lastModifiedTime().toMillis()));
                System.out.println(path.getFileName() + "\t" + size + "\t" + mtime);
            }
            System.out.println("Total " + ((List<Path>) stream).size() + " files in the current directory.");
        }
    }
}

请注意，此代码忽略了文件类型，所以如果你的当前目录下有子目录或其他非文件类型的项目，它们也会被列出来。此外，此代码假定你的Java程序在当前目录下运行，并且使用了Java 8的新特性，如果你使用其他版本的Java或其他操作系统，需要进行修改。