Java基於Runtime挪用內部法式湧現壅塞的處理辦法

Java基於Runtime挪用內部法式湧現壅塞的處理辦法。本站提示廣大學習愛好者：（Java基於Runtime挪用內部法式湧現壅塞的處理辦法）文章只能為提供參考，不一定能成為您想要的結果。以下是Java基於Runtime挪用內部法式湧現壅塞的處理辦法正文

本文實例講述了Java基於Runtime挪用內部法式湧現壅塞的處理辦法， 是一個很適用的技能。分享給年夜家供年夜家參考。詳細剖析以下：

有時刻在java代碼中會挪用一些內部法式，好比SwfTools來轉換swf、ffmpeg來轉換視頻等。假如你的代碼如許寫：Runtime.getRuntime().exec(command)，會發明法式一下就履行終了，而在敕令行裡要履行一會，是由於java沒有期待內部法式的履行終了，此時就須要應用壅塞，來期待內部法式履行成果：

InputStream stderr = process.getInputStream();
InputStreamReader isr = new InputStreamReader(stderr, "GBK");
BufferedReader br = new BufferedReader(isr);
String line = null;
while ((line = br.readLine()) != null)
  System.out.println(line);
int exitValue = process.waitFor();

關於普通的內部法式應用下面的壅塞代碼便可以，至多pdf2swf.exe是沒有成績的。

然則緊接著又發明關於ffmpeg來講，以上代碼會讓法式卡住不動，須要應用另外一種方法，封裝成了一個辦法，以下：

@SuppressWarnings("static-access")
public static int doWaitFor(Process process) {
  InputStream in = null;
  InputStream err = null;
  int exitValue = -1; // returned to caller when p is finished
  try {
    in = process.getInputStream();
    err = process.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 = process.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) {
    e.printStackTrace();
  } finally {
    try {
      if (in != null) {
        in.close();
      }
    } catch (IOException e) {
      e.printStackTrace();
    }
    if (err != null) {
      try {
        err.close();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }
  return exitValue;
}

願望本文所述對年夜家Java法式設計的進修有所贊助。