執行Java中的外部程序 - 巨大的CPU負載

Question

我有這樣的代碼在我的程序：

 ProcessBuilder builder = new ProcessBuilder(command); 

     builder.directory(new File(Vars.pathToForFfmpegBinDir)); 

     final Process process = builder.start(); 

     InputStream is = process.getErrorStream(); 
     InputStreamReader isr = new InputStreamReader(is); 
     BufferedReader br = new BufferedReader(isr); 
     String line; 
     while ((line = br.readLine()) != null) { 
      System.out.println("!!! "+line); 
     } 

由於外部程序得到很多輸出信息，它的加載每while週期一個CPU內核的100％。

我嘗試這種代碼的另一個版本：

 ProcessBuilder builder = new ProcessBuilder(command); 
     builder.redirectError(new File(pathToForModerationDir+"/1err.log")); 
     builder.redirectOutput(new File(pathToForModerationDir+"/1inp.log")); 
     builder.directory(new File(Vars.pathToForFfmpegBinDir)); 

     final Process process = builder.start(); 
     process.waitFor(); 

但它加載每個進程的一個CPU內核的100％。

如何在此代碼中減少CPU負載？

Answer 1

當我運行這個時，我試圖在top上找到它，但它使用的CPU不到0.1％，並且沒有出現在我的用戶標識的前20個進程中。

ProcessBuilder builder = new ProcessBuilder("sh", "-c", "while true; do sleep 1; date; done"); 
builder.redirectErrorStream(true); 
final Process process = builder.start(); 

try (BufferedReader br = new BufferedReader(new InputStreamReader(process.getInputStream()))) { 
    for (String line; (line = br.readLine()) != null;) 
     System.out.println("!!! " + line); 
}