本文介绍如何使用上传回调。

OSS在上传文件完成的时候可以提供回调（Callback）给应用服务器。您只需要在发送给OSS的请求中携带相应的Callback参数，即能实现回调。因为加入了回调请求和响应的过程，相比简单上传，使用回调通知机制一般会导致客户端花费更多的等待时间。

以下代码用于上传回调：

PutObjectRequest put = new PutObjectRequest(testBucket, testObject, uploadFilePath);

put.setCallbackParam(new HashMap<String, String>() {
	{
		put("callbackUrl", "110.75.82.106/callback");
        put("callbackHost", "oss-cn-hangzhou.aliyuncs.com");
        put("callbackBodyType", "application/json");
		put("callbackBody", "{\"mimeType\":${mimeType},\"size\":${size}}");
	}
});

OSSAsyncTask task = oss.asyncPutObject(put, new OSSCompletedCallback<PutObjectRequest, PutObjectResult>() {
	@Override
	public void onSuccess(PutObjectRequest request, PutObjectResult result) {
		Log.d("PutObject", "UploadSuccess");

		// 只有设置了servercallback，这个值才有数据
		String serverCallbackReturnJson = result.getServerCallbackReturnBody();

		Log.d("servercallback", serverCallbackReturnJson);
	}

	@Override
	public void onFailure(PutObjectRequest request, ClientException clientExcepion, ServiceException serviceException) {
		// 异常处理
	}
});

如果需要支持自定义参数，参考如下设置：

put.setCallbackParam(new HashMap<String, String>() {
    {
        put("callbackUrl", "http://182.92.192.125/leibin/notify.php");
        put("callbackHost", "oss-cn-hangzhou.aliyuncs.com");
        put("callbackBodyType", "application/json");
        put("callbackBody", "{\"object\":${object},\"size\":${size},\"my_var1\":${x:var1},\"my_var2\":${x:var2}}");
    }
});

put.setCallbackVars(new HashMap<String, String>() {
    {
        put("x:var1", "value1");
        put("x:var2", "value2");
    }
});

有关Callback的更多信息，请参考Callback API文档说明。