我应该为“.thrift”-file定义什么样的服务,以便稍后在我的程序中使用它？

此文件传输应位于客户端和服务器之间,它应该“部分”.

StreamFileService.thrift：

struct FileChunk {
1: binary data
2: i64 remaining
}

service StreamFileService {    
FileChunk getBytes(1:string fileName, 2: i64 offset, 3: i32 size);    
}

StreamFileClient.java：

public class StreamFileClient {
private int fileChunkSize = 16;
private String filePath;

public String getFilePath() {
    return filePath;
}

public void setFilePath(String filePath) {
    this.filePath = filePath;
}

private void invoke() {

    try {

        TTransport theClientTransport = new TFramedTransport(new TSocket(
                "127.0.0.1", 7911));
        TProtocol theProtocol = new TBinaryProtocol(theClientTransport);
        StreamFileService.Client theClient = new StreamFileService.Client(
                theProtocol);
        theClientTransport.open();

        filePath = "/home/output/output.pdf";
        File theFile2 = new File(filePath);
        theFile2.createNewFile();
        FileInputStream stream = new FileInputStream(theFile2);
        long currentPosition = 0;

        FileChannel theFileChannel = stream.getChannel();
        boolean again = true;

        do {
            FileChunk chunk2 = theClient.getBytes(filePath,
                    currentPosition, fileChunkSize);
            currentPosition += fileChunkSize;

            theFileChannel.write(chunk2.data);

            if (chunk2.remaining == 0)
                again = false;

        } while (again);
        stream.close();

    } catch (TTransportException e) {
        e.printStackTrace();
    } catch (TException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

public static void main(String[] args) {
    StreamFileClient theClient = new StreamFileClient();

    theClient.invoke();

}

}

StreamFileServer.java：

public class StreamFileServer {

private void start() {
    try {

        TNonblockingServerTransport theServerSocket = new TNonblockingServerSocket(
                7911);
        StreamFileService.Processor theProcessor = new StreamFileService.Processor(
                new StreamFileServiceImpl());
        TServer theServer = new TNonblockingServer(
                new TNonblockingServer.Args(theServerSocket)
                        .processor(theProcessor));
        System.out.println("Server starting on port 7911...");

        theServer.serve();

    } catch (TTransportException e) {
        e.printStackTrace();
    }

}

public static void main(String[] args) {
    StreamFileServer theFileServer = new StreamFileServer();
    theFileServer.start();
}

}

StreamFileServiceImpl：

  public class StreamFileServiceImpl implements StreamFileService.Iface {

public FileChunk getBytes(String filePath, long offset, int size)
        throws TException {

    File theFile = new File("/home/input/kl_12.pdf");
    FileChunk chunk = new FileChunk();

    try {

        FileOutputStream stream = new FileOutputStream(theFile);

        MappedByteBuffer buffer = stream.getChannel().map(
                FileChannel.MapMode.READ_ONLY, offset, size);
        chunk.data = buffer;
        chunk.remaining = stream.getChannel().size() - offset - size;
        stream.close();

    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return chunk;
}

}

解决方法:

您的代码对我来说并不是那么糟糕(未经过测试),并且没有太多变化.

怎么样

typedef binary binar
service StreamFileService {    
   binar getBytes(1:string fileName, 2: i64 offset, 3: i32 size);    
   i64 getSize(1:string fileName)
}

我还会返回一个包含字节的结构,但这或多或少是我的个人观点.

struct FileChunk {
  1: binary data
  2: i64 remaining
}

service StreamFileService {    
   FileChunk getBytes(1:string fileName, 2: i64 offset, 3: i32 size);    
}

如果需要,可以容易地扩展FileChunk结构,例如,为了返回额外的元数据,例如总大小(特别是如果大小随时间增长/缩小),剩余字节,关于数据格式的指示等.您不必这样做,因为如果以后需要这样做,您可以轻松扩展界面.味道很重要.