使用 SMBJ 客户端将数据附加到现有文件答案

【问题标题】：Append data to existing file using SMBJ client使用 SMBJ 客户端将数据附加到现有文件
【发布时间】：2021-06-13 23:30:42
【问题描述】：

我需要使用 SMBJ 客户端将数据附加到现有文件。以下代码追加数据，但最终文件已损坏，无法读取/打开文件。

 Set<AccessMask> accessMask = new HashSet<>();
 accessMask.add(AccessMask.GENERIC_READ);
 accessMask.add(AccessMask.GENERIC_WRITE);

 Set<FileAttributes> fileAttributes = new HashSet<>();
 fileAttributes.add(FileAttributes.FILE_ATTRIBUTE_NORMAL);

 Set<SMB2CreateOptions> createOptions = new HashSet<>();
 createOptions.add(SMB2CreateOptions.FILE_RANDOM_ACCESS);

 File file = share.openFile("PATH", accessMask, fileAttributes, SMB2ShareAccess.ALL, 
                         SMB2CreateDisposition.FILE_OPEN_IF, createOptions);

 // Approach - 1
 long fileOffset = 0;
 byte[] buffer = new byte[1024*4];
 int length = inputStream.read(buffer);
 while(length != -1){
   fileOffset = share.getFileInformation("PATH").getStandardInformation().getEndOfFile();
   file.write(buffer, fileOffset, 0, lenght);
 }

//Approach - 2
 OutputStream oStream = f.getOutputStream();
     oStream.write(fileContents.getBytes());
     oStream.flush();
     oStream.close();

但是从这两种方法来看，都无法正确附加数据。

【问题讨论】：

标签： java smb smbj

【解决方案1】：

这就是我的做法：

private static void uploadAppend(File source, DiskShare diskShare,
        String destPath) throws IOException {
    if (source != null && source.exists() && source.canRead()
            && source.isFile()) {

        try (InputStream is = new java.io.FileInputStream(source)) {
            if (destPath != null && is != null) {
                Set<AccessMask> accessMask = new HashSet<>(EnumSet.of(
                        AccessMask.FILE_READ_DATA,
                        AccessMask.FILE_WRITE_DATA, AccessMask.DELETE));
                Set<SMB2ShareAccess> shareAccesses = new HashSet<>(
                        EnumSet.of(SMB2ShareAccess.FILE_SHARE_READ,
                                SMB2ShareAccess.FILE_SHARE_WRITE,
                                SMB2ShareAccess.FILE_SHARE_DELETE));
                Set<FileAttributes> createOptions = new HashSet<>(
                        EnumSet.of(FileAttributes.FILE_ATTRIBUTE_NORMAL));

                try (com.hierynomus.smbj.share.File file = diskShare
                        .openFile(destPath, accessMask, createOptions,
                                shareAccesses,
                                SMB2CreateDisposition.FILE_OPEN_IF,
                                EnumSet.noneOf(SMB2CreateOptions.class))) {

                    int bufferSize = 2048;
                    if (source.length() > 20971520l) {
                        bufferSize = 131072;
                    }
                    byte[] buffer = new byte[bufferSize];
                    long fileOffset = 0;
                    int length = 0;
                    while ((length = is.read(buffer)) > 0) {
                        fileOffset = diskShare.getFileInformation(destPath)
                                .getStandardInformation().getEndOfFile();
                        file.write(buffer, fileOffset, 0, length);
                    }
                    file.flush();
                    file.close();
                } finally {
                    is.close();
                }
            }
        }
    }
}

【讨论】：

【解决方案2】：

下面是jcifs.smb.SmbFileOutputStream 和jcifs.smb.SmbFileInputStream 类的解决方案：

private void AppendToFile() throws Exception {
        CIFSContext base = SingletonContext.getInstance();
        CIFSContext context = base.withCredentials(new NtlmPasswordAuthentication(base, "domainName",
                "userName", "password"));
        try (SmbFile f = new SmbFile("smb://serverName/folder/test.txt", context)) {
            SmbFileInputStream in = new SmbFileInputStream(f);
            byte[] buffer = new byte[1024]; //your file size
            int bytesRead = in.read(buffer);
            while (bytesRead > 0) {
                bytesRead = in.read(buffer);
            }
            in.close();

//...
//do your operations with the data in buffer
//...


            SmbFileOutputStream out = f.openOutputStream(true); //true is for append mode
            out.write(buffer);
            out.close();
        }
    }

【讨论】：