Java 上传大文件的代码

上传大文件的代码可以通过分块上传来实现，以下是一个示例：

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

import org.apache.commons.codec.binary.Base64;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class FileUploader {
    private static final int CHUNK_SIZE = 512 * 1024; // 512KB

    public static void upload(File file, String uploadUrl) throws IOException {
        CloseableHttpClient httpClient = HttpClients.createDefault();

        // 1. 分块上传
        FileInputStream inputStream = new FileInputStream(file);
        byte[] buffer = new byte[CHUNK_SIZE];
        int bytesRead = -1;
        int chunkIndex = 0;
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            String chunkData = Base64.encodeBase64String(buffer);
            String chunkUrl = uploadUrl + "?chunkIndex=" + chunkIndex;
            HttpPost chunkUploadRequest = new HttpPost(chunkUrl);
            chunkUploadRequest.setHeader("Content-Type", "application/json;charset=UTF-8");
            chunkUploadRequest.setEntity(new StringBody(chunkData, ContentType.APPLICATION_JSON));
            HttpResponse chunkUploadResponse = httpClient.execute(chunkUploadRequest);
            if (chunkUploadResponse.getStatusLine().getStatusCode() != HttpStatus.SC_OK) {
                throw new IOException("Failed to upload chunk " + chunkIndex + ", status code: " + chunkUploadResponse.getStatusLine().getStatusCode());
            }
            chunkIndex++;
        }
        inputStream.close();

        // 2. 合并分块
        String mergeUrl = uploadUrl + "?merge=true";
        HttpPost mergeRequest = new HttpPost(mergeUrl);
        HttpResponse mergeResponse = httpClient.execute(mergeRequest);
        HttpEntity mergeEntity = mergeResponse.getEntity();
        if (mergeResponse.getStatusLine().getStatusCode() != HttpStatus.SC_OK) {
            EntityUtils.consume(mergeEntity);
            throw new IOException("Failed to merge chunks, status code: " + mergeResponse.getStatusLine().getStatusCode());
        }
        EntityUtils.consume(mergeEntity);

        httpClient.close();
    }
}

这个代码示例使用了 Apache HttpComponents 库来进行 HTTP 请求，其中 `CHUNK_SIZE` 是指每个分块的大小，根据需要可以调整。具体的上传 URL 需要根据实际情况进行替换。