java 多线程上传文件

在Java中使用多线程上传文件可以提高上传速度和效率。下面是一个简单的示例代码，演示了如何使用多线程上传文件：

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class FileUploader implements Runnable {
    private String url;
    private File file;

    public FileUploader(String url, File file) {
        this.url = url;
        this.file = file;
    }

    @Override
    public void run() {
        try {
            uploadFile();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void uploadFile() throws IOException {
        HttpURLConnection connection = null;
        FileInputStream inputStream = null;
        OutputStream outputStream = null;

        try {
            URL uploadUrl = new URL(url);
            connection = (HttpURLConnection) uploadUrl.openConnection();
            connection.setDoOutput(true);
            connection.setRequestMethod("POST");

            inputStream = new FileInputStream(file);
            outputStream = connection.getOutputStream();

            byte[] buffer = new byte[4096];
            int bytesRead;
            while ((bytesRead = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, bytesRead);
            }

            int responseCode = connection.getResponseCode();
            if (responseCode == HttpURLConnection.HTTP_OK) {
                System.out.println("文件上传成功");
            } else {
                System.out.println("文件上传失败");
            }
        } finally {
            if (connection != null) {
                connection.disconnect();
            }
            if (inputStream != null) {
                inputStream.close();
            }
            if (outputStream != null) {
                outputStream.close();
            }
        }
    }
}

使用示例：

public class Main {
    public static void main(String[] args) {
        String url = "http://example.com/upload";
        File file = new File("path/to/file");

        FileUploader uploader = new FileUploader(url, file);
        Thread thread = new Thread(uploader);
        thread.start();
    }
}

在上述示例中，FileUploader类实现了Runnable接口，并在run()方法中执行文件上传的逻辑。在uploadFile()方法中，首先创建URL对象并打开连接，然后设置请求方法为POST，并将文件内容通过输出流写入到服务器。最后，根据服务器的响应码判断上传是否成功。

通过创建多个FileUploader对象，并将其放入不同的线程中运行，可以实现多线程上传多个文件。每个线程独立处理一个文件的上传任务，从而提高上传速度和效率。

请注意，这只是一个简单的示例，实际应用中可能还需要处理异常、添加进度监控等功能。