Java File SDK

本节介绍如何将大文件传输功能以jar包形式直接集成到业务服务里。

前置条件

• 区块链FISCO-BCOS节点

  必选配置。WeEvent通过区块链FISCO-BCOS的P2P网络发布和订阅文件。

  具体安装步骤，请参见FISCO-BCOS安装。

集成SDK

• gradle依赖

implement 'com.webank.weevent:weevent-file:1.3.0'

• maven依赖

<dependency>
    <groupId>com.webank.weevent</groupId>
    <artifactId>weevent-file</artifactId>
    <version>1.3.0</version>
</dependency>

API接口

public interface IWeEventFileClient {
    static IWeEventFileClient build(String groupId, String filePath, int fileChunkSize, FiscoConfig fiscoConfig) {
        return new WeEventFileClient(groupId, filePath, fileChunkSize, fiscoConfig);
    }

    static IWeEventFileClient build(String groupId, String filePath, FtpInfo ftpInfo, int fileChunkSize, FiscoConfig fiscoConfig) {
        return new WeEventFileClient(groupId, filePath, ftpInfo, fileChunkSize, fiscoConfig);
    }

    /**
     * open transport for sender.
     *
     * @param topic topic name
     */
    void openTransport4Sender(String topic);

    /**
     * open transport for authentication sender.
     *
     * @param topic topic name
     * @param publicPem public pem InputStream
     * @throws BrokerException broker exception
     */
    void openTransport4Sender(String topic, InputStream publicPem) throws BrokerException;

    /**
     * open transport for authentication sender.
     *
     * @param topic topic name
     * @param publicPem public pem path string
     * @throws BrokerException broker exception
     * @throws BrokerException BrokerException
     */
    void openTransport4Sender(String topic, String publicPem) throws BrokerException, IOException;

    /**
     * Publish a file to topic.
     * The file's data DO NOT stored in block chain. Yes, it's not persist, may be deleted sometime after subscribe notify.
     *
     * @param topic binding topic
     * @param localFile local file to be send
     * @param overwrite if receiver has this file, overwrite it?
     * @return send result, SendResult.SUCCESS if success, and return SendResult.eventId
     * @throws BrokerException broker exception
     * @throws IOException IOException
     */
    FileChunksMeta publishFile(String topic, String localFile, boolean overwrite) throws BrokerException, IOException;

    /**
     * open transport for receiver.
     *
     * @param topic topic name
     * @param fileListener notify interface
     * @throws BrokerException broker exception
     */
    void openTransport4Receiver(String topic, FileListener fileListener) throws BrokerException;

    /**
     * open transport for authentication receiver.
     *
     * @param topic topic name
     * @param fileListener notify interface
     * @param privatePem private key pem InputStream
     * @throws BrokerException broker exception
     */
    void openTransport4Receiver(String topic, FileListener fileListener, InputStream privatePem) throws BrokerException;

    /**
     * open transport for authentication receiver.
     *
     * @param topic topic name
     * @param fileListener notify interface
     * @param privatePem private key pem path string
     * @throws IOException IOException
     * @throws BrokerException BrokerException
     */
    void openTransport4Receiver(String topic, FileListener fileListener, String privatePem) throws IOException, BrokerException;


    /**
     * Interface for file notify callback
     */
    interface FileListener {
        /**
         * Called while new file arrived.
         *
         * @param topicName topic name
         * @param fileName file name
         */
        void onFile(String topicName, String fileName);

        /**
         * Called while raise exception.
         *
         * @param e the e
         */
        void onException(Throwable e);
    }

    /**
     * close transport.
     *
     * @param topic topic name
     */
    void closeTransport(String topic);

    /**
     * query transport status.
     *
     * @param topic topic name
     * @return FileTransportStats
     */
    FileTransportStats status(String topic);

    /**
     * list received files.
     *
     * @param topic topic name
     * @return FileChunksMeta list
     * @throws BrokerException broker exception
     */
    List<FileChunksMeta> listFiles(String topic) throws BrokerException;

    /**
     * sign a file transport event.
     *
     * @param fileChunksMeta fileChunksMeta
     * @return send result and eventId
     * @throws BrokerException broker exception
     */
    SendResult sign(FileChunksMeta fileChunksMeta) throws BrokerException;

    /**
     * verify a file transport event.
     *
     * @param eventId eventId return by sign
     * @param groupId group id
     * @return file and block information
     * @throws BrokerException broker exception
     */
    FileChunksMetaPlus verify(String eventId, String groupId) throws BrokerException;

    /**
     * get DiskFiles.
     *
     * @return DiskFiles
     */
    DiskFiles getDiskFiles();

    /**
     * generate pem key pair.
     *
     * @param filePath output pem file path
     * @throws BrokerException BrokerException
     */
    void genPemFile(String filePath) throws BrokerException;
    
    /**
     * Check if the receiver end has a file.
     *
     * @param fileName file name
     * @param topic topic name
     * @param groupId group id
     * @return is file exist
     * @throws BrokerException BrokerException
     */
    boolean isFileExist(String fileName, String topic, String groupId) throws BrokerException;
}

代码样例

public static void main(String[] args) {
    try {
        FiscoConfig fiscoConfig = new FiscoConfig();
        fiscoConfig.load("");
        
        IWeEventFileClient weEventFileClient = IWeEventFileClient.build("1", "./logs", 1024 * 1024, fiscoConfig);
        String topicName = "com.weevent.file";

        // 订阅文件，接收到的文件存到"./logs"目录中
        weEventFileClient.openTransport4Receiver(topicName, new IWeEventFileClient.FileListener() {
            @Override
            public void onFile(String topicName, String fileName) {
                // 接收到文件，业务处理中
            }

            @Override
            public void onException(Throwable e) {
                e.printStackTrace();
            }
        });

        // 发布文件"log4j2.xml"
        weEventFileClient.openTransport4Sender(topicName);
        FileChunksMeta fileChunksMeta = weEventFileClient.publishFile(topicName,
                new File("src/main/resources/log4j2.xml").getAbsolutePath(), true);  

        // 对文件传输事件上链(可选)
        SendResult sendResult = weEventFileClient.sign(fileChunksMeta);
        
        // 验证文件传输事件(可选)
        FileChunksMetaPlus fileChunksMetaPlus = weEventFileClient.verify(sendResult.getEventId(), this.groupId);
          
    } catch (Exception e) {
        e.printStackTrace();
    }
}