java oss文件下载进度条

你可以使用阿里云的Java SDK来实现OSS文件下载，并且通过多线程和进度条来显示下载进度。以下是一个示例代码：

import com.aliyun.oss.OSS;
import com.aliyun.oss.event.ProgressEvent;
import com.aliyun.oss.event.ProgressEventType;
import com.aliyun.oss.event.ProgressListener;
import com.aliyun.oss.model.GetObjectRequest;
import com.aliyun.oss.model.OSSObject;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class OSSDownloadWithProgress {
    private static final String ACCESS_KEY_ID = "<yourAccessKeyId>";
    private static final String ACCESS_KEY_SECRET = "<yourAccessKeySecret>";
    private static final String ENDPOINT = "<yourEndpoint>";
    private static final String BUCKET_NAME = "<yourBucketName>";
    private static final String OBJECT_KEY = "<yourObjectKey>";
    private static final String DOWNLOAD_FILE_NAME = "<yourDownloadFileName>";
    private static final int THREAD_POOL_SIZE = 5;

    public static void main(String[] args) {
        // 创建OSSClient实例
        OSS ossClient = new OSSClientBuilder().build(ENDPOINT, ACCESS_KEY_ID, ACCESS_KEY_SECRET);

        // 创建线程池
        ExecutorService executorService = Executors.newFixedThreadPool(THREAD_POOL_SIZE);

        // 创建GetObjectRequest对象并设置进度监听器
        GetObjectRequest getObjectRequest = new GetObjectRequest(BUCKET_NAME, OBJECT_KEY);
        getObjectRequest.setProgressListener(new ProgressListener() {
            private long bytesWritten = 0;
            private long totalBytes = -1;
            private boolean succeed = false;

            @Override
            public void progressChanged(ProgressEvent progressEvent) {
                long bytes = progressEvent.getBytes();
                ProgressEventType eventType = progressEvent.getEventType();
                switch (eventType) {
                    case TRANSFER_STARTED_EVENT:
                        System.out.println("Start to download...");
                        break;
                    case RESPONSE_CONTENT_LENGTH_EVENT:
                        this.totalBytes = bytes;
                        System.out.println(this.totalBytes + " bytes in total will be downloaded to a local file");
                        break;
                    case RESPONSE_BYTE_TRANSFER_EVENT:
                        this.bytesWritten += bytes;
                        if (this.totalBytes != -1) {
                            int percent = (int) (this.bytesWritten * 100.0 / this.totalBytes);
                            System.out.println(bytes + " bytes have been written at this time, download progress: " + percent + "% (" + this.bytesWritten + "/" + this.totalBytes + ")");
                        } else {
                            System.out.println(bytes + " bytes have been written at this time, download ratio: unknown" + "(" + this.bytesWritten + "/...)");
                        }
                        break;
                    case TRANSFER_COMPLETED_EVENT:
                        this.succeed = true;
                        System.out.println("Succeed to download, " + this.bytesWritten + " bytes have been transferred in total");
                        break;
                    case TRANSFER_FAILED_EVENT:
                        System.out.println("Failed to download, " + this.bytesWritten + " bytes have been transferred");
                        break;
                    default:
                        break;
                }
            }
        });

        // 提交下载任务到线程池
        executorService.submit(() -> {
            try {
                // 下载OSS文件到本地
                OSSObject ossObject = ossClient.getObject(getObjectRequest);
                BufferedInputStream in = new BufferedInputStream(ossObject.getObjectContent());
                File file = new File(DOWNLOAD_FILE_NAME);
                FileOutputStream out = new FileOutputStream(file);
                byte[] buffer = new byte[8192];
                int len;
                while ((len = in.read(buffer)) != -1) {
                    out.write(buffer, 0, len);
                }
                out.close();
                in.close();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                // 关闭OSSClient和线程池
                ossClient.shutdown();
                executorService.shutdown();
            }
        });
    }
}

在上面的代码中，我们通过创建GetObjectRequest对象并设置进度监听器来实现OSS文件的下载进度显示。然后，我们将下载任务提交到线程池中，并在下载完成后关闭OSSClient和线程池。