java Runtime Process调用可执行文件，子进程阻塞

我用java调用mencoder实施转码，但是转码过程中出现子进程阻塞，而且还是看了API才知道这个问题的。因为mencoder的控制台输出信息很多，把缓存区所有的空间占满了，所以程序不能执行后面的程序，mencoder就只能转码28秒的视频，所以需要建立线程及时清空缓存区。

新建一个类StreamGobble类：

 

package thss.jmencoder; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; public class StreamGobble extends Thread { InputStream is; String type; StreamGobble(InputStream is, String type) { this.is = is; this.type = type; } public void run() { try { InputStreamReader isr = new InputStreamReader(is); BufferedReader br = new BufferedReader(isr); String line = null; while ((line = br.readLine()) != null) System.out.println(type + ">" + line); } catch (IOException ioe) { ioe.printStackTrace(); } } }

 

在main函数中调用Runtime/Process执行转码

 

String line = value.toString(); String[] str = line.split(" "); String fOutput = null; fOutput = str[3] + ".flv"; Process process = null; try { Runtime runtime = Runtime.getRuntime(); process = runtime .exec("mencoder -ofps 30000/1001 -vf harddup" + " /user/student/data/"+str[0] + " -ss "+str[1]+" -endpos "+str[2]+" -sws 2 -of lavf -ovc lavc -lavcopts " + "vcodec=flv:vbitrate=500:mbd=2:mv0:trell:v4mv:cbp:last_pred=3 " + "-nosound -srate 22050 -o /user/student/data/"+fOutput); new StreamGobble(process.getInputStream(), "INFO").start(); new StreamGobble(process.getErrorStream(), "ERROR").start(); int status = process.waitFor(); System.out.println("Process exitValue: " + status); } catch (Throwable t) { t.getStackTrace(); } finally { if (process == null) process.destroy(); process = null; }