Java开发指南：快速对接七牛云云存储服务

<dependency>
    <groupId>com.qiniu</groupId>
    <artifactId>qiniu-java-sdk</artifactId>
    <version>7.0.0</version>
</dependency>

// 七牛云配置参数
String accessKey = "your-access-key";
String secretKey = "your-secret-key";
String bucket = "your-bucket-name";
String domain = "your-bucket-domain";
Auth auth = Auth.create(accessKey, secretKey);

// 创建上传管理器
UploadManager uploadManager = new UploadManager();

// 设置上传策略
StringMap policy = new StringMap();
policy.put("returnBody", "{"key":"$(key)","hash":"$(etag)","bucket":"$(bucket)","fname":"$(x:fname)"}");

// 构建上传凭证
String upToken = auth.uploadToken(bucket, null, 3600, policy);

// 指定本地文件路径和文件名，并设置文件上传后的文件名
String localFilePath = "/path/to/your/local/file";
String key = "your-upload-key";

try {
    // 执行文件上传
    Response response = uploadManager.put(localFilePath, key, upToken);
    // 获取上传结果
    DefaultPutRet putRet = new Gson().fromJson(response.bodyString(), DefaultPutRet.class);
    // 打印上传结果
    System.out.println("上传成功，文件key：" + putRet.key + "，hash：" + putRet.hash);
} catch (QiniuException ex) {
    Response r = ex.response;
    System.err.println(r.toString());
}

// 文件下载地址
String downloadUrl = "http://" + domain + "/" + key;

// 生成文件下载链接
String finalUrl = auth.privateDownloadUrl(downloadUrl, 3600);

// 执行文件下载
URL url = new URL(finalUrl);
URLConnection conn = url.openConnection();
InputStream inputStream = conn.getInputStream();

// 保存文件到本地
String saveFilePath = "/path/to/save/file";
FileOutputStream outputStream = new FileOutputStream(saveFilePath);
byte[] buffer = new byte[1024];
int bytesRead;
while ((bytesRead = inputStream.read(buffer)) != -1) {
    outputStream.write(buffer, 0, bytesRead);
}
outputStream.close();
inputStream.close();

System.out.println("文件下载成功，保存路径为：" + saveFilePath);

// 指定文件的存储Key
String deleteKey = "your-delete-key";

// 执行文件删除
try {
    Response response = bucketManager.delete(bucket, deleteKey);
    System.out.println("文件删除成功，状态码：" + response.statusCode);
} catch (QiniuException ex) {
    Response r = ex.response;
    System.err.println(r.toString());
}