来自Java的pg_dump无法生成备份文件

Question

我正在尝试从Java调用pg_dump。这是我要执行的命令。但是--file参数中指定的文件未创建。

/usr/local/Cellar/postgresql@9.6/9.6.10_1/bin/pg_dump --format=t --verbose --file=/Users/abc/Downloads/backups/backup-1549946580007.backup --no-password

这是我用来执行相同代码的代码。我正在使用Apache commons exec执行命令。我还尝试过ProcessBuilder和Process来执行相同的操作。

    cmd = "sh";
    cmdArg = "-c";
    pgCmdArg = System.getenv("POSTGRES_BIN") + "pg_dump";
    pgVerboseArg = "--verbose";
    fileArg = "--file=" + inputFile;
    noPassWordArg = "--no-password";
    Map<String, String> env=new HashMap<>();
    env.put("PGHOST", "localhost");
    env.put("PGUSER", dbUserName);
    env.put("PGPASSWORD", dbPass);
    env.put("PGPORT", "5432");
    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
    CommandLine commandline = CommandLine.parse(cmd).addArgument(cmdArg).addArgument(pgCmdArg)
                        .addArgument("--format=t").addArgument(pgVerboseArg).addArgument(fileArg)
                        .addArgument(noPassWordArg).addArgument(dbName);

    DefaultExecutor exec = new DefaultExecutor();
    PumpStreamHandler streamHandler = new 
    PumpStreamHandler(outputStream);
    exec.setStreamHandler(streamHandler);
   int exitCode = exec.execute(commandline, env);

知道为什么不创建文件吗？