使用StreamGobbler处理输入

Question

我通过以下URL浏览了StreamGobbler

JavaWorld:Stream Gobbler

我理解它的用法和原因.但是,所涵盖的场景只是那些可能存在来自命令/处理错误的输出的场景.

我没有找到使用StreamGobbler来处理输入的任何场景.例如,在mailx,我必须指定电子邮件的正文,我已按以下格式完成

Process proc = Runtime.getRuntime().exec(cmd);
OutputStreamWriter osw = new OutputStreamWriter(proc.getOutputStream());
osw.write(mailBody);
osw.close();

如何通过StreamGobbler处理,或者不需要通过它处理它.

Answer 1

理想情况下,StreamGobbler如果您已经在期待某些内容InputStream,则可以使用错误流(在单独的线程中),查看何时process.waitFor()返回非零值以查找错误消息.如果您对此不感兴趣InputStream,那么一旦完成对命令的输入,您就可以直接在代码中读取ErrorStream.

Process proc = Runtime.getRuntime().exec(cmd)
// Start a stream gobbler to read the error stream.
StreamGobbler errorGobbler = new StreamGobbler(proc.getErrorStream());
errorGobbler.start();

OutputStreamWriter osw = new OutputStreamWriter(proc.getOutputStream())
osw.write(mailBody)
osw.close();

int exitStatus = proc.waitFor();
if (0 != exitStatus) {
    /*
     * If you had not used a StreamGobbler to read the errorStream, you wouldn't have
     * had a chance to know what went wrong with this command execution.
     */
    LOG.warn("Error while sending email: " + errorGobbler.getContent());
}