查了好多資料，差點就動手翻Java源碼了，最後結合一篇文章（忘記出處了），想到了輸出流會阻塞進程執行。 Java進程執行有一個輸入流，兩個輸出流(相對於外部程序)。當兩個輸出流有內容輸出，而Java執行程序沒有及時清空輸出流時就會阻塞進程。
現貼出代碼，希望能幫助到有需要的同行：
複製代碼代碼如下:/**
* pdf轉swf函數
* @param path 輸入輸出文件路徑
* @param inputFileName 輸入文件名
* @param outputFileName 輸出文件名
* @return File 生成的swf文件
*/
private static File toSwf(String sourceFile, String destFile, String command) {
long beginTime = System.nanoTime();
Runtime rt = Runtime.getRuntime();
try {
Process process = rt.exec(command);
final InputStream isNormal = process.getInputStream();
new Thread(new Runnable() {
public void run() {
BufferedReader br = new BufferedReader(new InputStreamReader(isNormal));
StringBuilder buf = new StringBuilder();
String line = null;
try {
while((line = br.readLine()) != null){
buf.append(line + "/n");
}
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("輸出結果為：" + buf);
}
}).start(); // 啟動單獨的線程來清空process.getInputStream()的緩衝區
InputStream isError = process.getErrorStream();
BufferedReader br2 = new BufferedReader(new InputStreamReader(isError));
StringBuilder buf = new StringBuilder();
String line = null;
while((line = br2.readLine()) != null){
buf.append(line + "/n");
}
System.out.println("錯誤輸出結果為：" + buf);
try {
process.waitFor();
} catch (InterruptedException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}
long endTime = System.nanoTime();
System.out.println("轉swf耗時: " + (endTime - beginTime) / 1000000000 + " 秒" + sourceFile);
return new File(destFile);
}