Question

在下面的代码中，作者使用Runtime来调用子流程。但我不明白为什么他会使用StreamGobbler。如果用InputStream替换它会发生什么？请帮助我，谢谢！

public class GoodWindowsExec   
{   
    public static void main(String args[])   
    {   

        try   
        {               
            String osName = System.getProperty("os.name" );   
            System.out.println("osName: " + osName);   
            String[] cmd = new String[3];   

            if(osName.equals("Windows XP") ||osName.equals("Windows 2000"))   
            {   
                cmd[0] = "cmd.exe" ;   
                cmd[1] = "/C" ;   
                cmd[2] = args[0];   
            }   
            else if( osName.equals( "Windows 98" ) )   
            {   
                cmd[0] = "command.com" ;   
                cmd[1] = "/C" ;   
                cmd[2] = args[0];   
            }   

            Runtime rt = Runtime.getRuntime();   
            System.out.println("Execing " + cmd[0] + " " + cmd[1]+ " " + cmd[2]);   
            Process proc = rt.exec(cmd);   
            // any error message?   
            StreamGobbler errorGobbler = new StreamGobbler(proc.getErrorStream(), "ERROR");  //Can I replace StreamGobbler by InputStream?        
            // any output?   
            StreamGobbler outputGobbler = new StreamGobbler(proc.getInputStream(), "OUTPUT");   //As above

            // kick them off   
            errorGobbler.start();   
            outputGobbler.start();   

            // any error???   
            int exitVal = proc.waitFor();   
            System.out.println("ExitValue: " + exitVal);   

        } catch (Throwable t){   
            t.printStackTrace();   
        }   
    }   
}

BufferedReader brNormal = new BufferedReader(new InputStreamReader(process.getInputStream()));
String s = null;
while ((s = brNormal.readLine()) != null) {
    logger.info("RawToRgbConverter.exe", s);
}
brNormal.close();
BufferedReader brError = new BufferedReader(new InputStreamReader(process.getErrorStream()));
while ((s = brError.readLine()) != null) {
    logger.error("RawToRgbConverter.exe", s);
}
brError.close();

Answer 1

即使我不了解StreamGobbler类，这显然是一个将输出和错误流复制到给定目标的线程实现。因此，不能简单地替换它，因为多线程确实是必要的。一个简单的输入流只会坐在那里，但实际上并没有做任何事情。

但请注意，自Java 1.5引入ProcessBuilder和自动重定向以来，这个完整的解决方案已经过时了。请参阅https://docs.oracle.com/javase/8/docs/api/

上的javadoc

InputStream和StreamGobbler之间的区别是什么？

1 个答案: