Apache 事务：如何以事务方式移动文件

Question

使用案例： 需要以事务方式将文件从一个位置移动到另一个位置。如果操作失败，则必须回滚相应的操作。

我选择了 Apache Commons Transaction 库。

我尝试使用 FileResourceManager 中的 moveResource 函数，下面是我的代码。

代码：

    public static void moveFiles() throws ResourceManagerException {
            FileResourceManager fileResourceManager=null;
            String txId = null;
            try {
                String workDir = "D:\\source";
                String storeDir = "D:\\destination";
    
                fileResourceManager = new FileResourceManager(storeDir, workDir, false, LOGGER_FACADE,true);
    
                fileResourceManager.start();
                txId = fileResourceManager.generatedUniqueTxId();
                fileResourceManager.startTransaction(txId);
    
                fileResourceManager.moveResource(txId,workDir,storeDir,true);
    
                fileResourceManager.commitTransaction(txId);
                //if any exception arises rollback
            } catch (ResourceManagerException resourceManagerException) {
                fileResourceManager.rollbackTransaction(txId);
                resourceManagerException.printStackTrace();
            }
        }
    
    Is it a right way to move files ? , below is my source directory (where file present) and destination directory (where file needs to be moved)
[![source and destination directories][1]][1]


  [1]: https://i.stack.imgur.com/oS6x5.png

Answer 1

要以事务方式实现此操作，您可以复制整个文件，然后从源位置删除。如果我们直接尝试移动文件，则在失败的情况下其内容可能会损坏，因此回滚将无济于事。

public static void moveFiles() throws Exception {

            Path source = Paths.get("C:\\sourced\\A.txt");
            Path destination = Paths.get("C:\\destination",source.getFileName().toString());
            Path fileToBeDeleted = source;
            try {
                Files.createFile(destination);
                Files.copy(source, destination, StandardCopyOption.COPY_ATTRIBUTES);
            }catch (Exception e){
                logger.log(Level.WARNING,"Error while copyingFile to destination");
                fileToBeDeleted = destination;
            }finally {
                try {
                    Files.deleteIfExists(fileToBeDeleted);
                }catch (Exception e){
                    logger.log(Level.SEVERE,"File not deleted from source/destination");
                    throw new IllegalStateException("Error while deleting file in source/destination "+fileToBeDeleted);
                }
            }

    }

上述实现是使用

java.nio

包完成的。您可以使用 apache 实用程序进行文件操作 ApacheFileUtil