java获取本地io速度

要获取本地IO速度，可以使用Java的NIO（New IO）库中的ByteBuffer和FileChannel类来实现。下面是一个示例代码：

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

public class IOBenchmark {

    public static void main(String[] args) throws IOException {
        File inputFile = new File("input.txt");
        File outputFile = new File("output.txt");
        int bufferSize = 1024 * 1024; // 1MB buffer size

        long startTime = System.currentTimeMillis();
        copyFile(inputFile, outputFile, bufferSize);
        long endTime = System.currentTimeMillis();

        long duration = endTime - startTime;
        double fileSize = inputFile.length() / 1024.0 / 1024.0;
        double ioSpeed = fileSize / (duration / 1000.0);

        System.out.printf("IO speed: %.2f MB/s\n", ioSpeed);
    }

    public static void copyFile(File inputFile, File outputFile, int bufferSize) throws IOException {
        try (FileInputStream inputStream = new FileInputStream(inputFile);
             FileOutputStream outputStream = new FileOutputStream(outputFile);
             FileChannel inputChannel = inputStream.getChannel();
             FileChannel outputChannel = outputStream.getChannel()) {

            ByteBuffer buffer = ByteBuffer.allocate(bufferSize);
            while (inputChannel.read(buffer) != -1) {
                buffer.flip();
                outputChannel.write(buffer);
                buffer.clear();
            }
        }
    }
}

这个程序会从本地文件系统中读取一个文件，并将其拷贝到另一个文件中，然后计算拷贝速度。你可以根据自己的需求修改bufferSize值来测试不同大小的缓冲区大小对IO速度的影响。