process阻塞

 调用系统其他进程，未等被启动进程进行完，java主进程就继续往下执行了，本以为调用procc.waitfor()可以解决问题，未果，google之发现如下方法：

代码：

//对process.waitFor()的改造，被启动的进程会因为缓冲区不够而被阻塞无法启动，调用该方法可以成功
public static int doWaitFor(Process p) { 
int exitValue = -1; // returned to caller when p is finished 
try { 
InputStream in = p.getInputStream(); 
InputStream err = p.getErrorStream(); 
boolean finished = false; // Set to true when p is finished 
while(!finished) { 
try { 
while( in.available() > 0) { 
// Print the output of our system call 
Character c = new Character( (char) in.read()); 
System.out.print( c); 
} 
while( err.available() > 0) { 
// Print the output of our system call 
Character c = new Character( (char) err.read()); 
System.out.print( c); 
} 
// Ask the process for its exitValue. If the process 
// is not finished, an IllegalThreadStateException 
// is thrown. If it is finished, we fall through and 
// the variable finished is set to true. 
exitValue = p.exitValue(); 
finished = true; 
} catch (IllegalThreadStateException e) { 
// Process is not finished yet; 
// Sleep a little to save on CPU cycles 
Thread.currentThread().sleep(500); 
} 
} 
} catch (Exception e) { 
// unexpected exception! print it out for debugging... 
System.err.println( "doWaitFor(): unexpected exception - " + 
e.getMessage()); 
} 
// return completion status to caller 
return exitValue; 
}

 

 

评论

1 楼 manbanpaic 2012-11-15  

谢谢了  问题终于解决了