我有一個像這樣的簡單類：public class Dog { public static void main(String[] args) { System.out.println("DOG"); }}它被編譯成Dog.class位于里面C:\Program Files\Apache Software Foundation\Tomcat 8.5\webapps\Test\classes。我嘗試使用 ProcessBuilder 運行它：public static void main(String[] args) { String pathName = "-cp \"C:\\Program Files\\Apache Software Foundation\\Tomcat 8.5\\webapps\\Test\\classes" + "\" " + "Dog"; runCode(pathName); }public static void runCode(String name) { System.out.println(name); //-cp "C:\Program Files\Apache Software Foundation\Tomcat 8.5\webapps\Test\classes" Dog ProcessBuilder processBuilder = new ProcessBuilder("java " + name); processBuilder.redirectError(new File(Paths.get("C:\\Program Files\\Apache Software Foundation\\Tomcat 8.5\\webapps\\JavaStudyRooms\\output.txt").toString())); processBuilder.redirectInput(); try { final Process process = processBuilder.start(); try { final int exitStatus = process.waitFor(); if(exitStatus==0){ System.out.println("External class Started Successfully."); System.exit(0); //or whatever suits }else{ System.out.println("There was an error starting external class. Perhaps path issues. Use exit code "+exitStatus+" for details."); System.out.println("Check also output file for additional details."); System.exit(1);//whatever } } catch (InterruptedException ex) { System.out.println("InterruptedException: "+ex.getMessage()); } } catch (IOException ex) { System.out.println("IOException. Faild to start process. Reason: "+ex.getMessage()); } System.out.println("Process Terminated."); System.exit(0); }為什么會發生這種情況以及如何解決？
1 回答
holdtom
TA貢獻1805條經驗 獲得超10個贊
ProcessBuilder 不使用整個命令行。它需要爭論。
例如，您當前的代碼正在尋找一個基本名稱長度為 90 個字符的程序java -cp … Dog.exe。
您需要傳遞一個參數數組：
// Note the use of a String array, not a single String
public static void runCode(String... javaArgs) {
List<String> args = new ArrayList<>();
args.add("java");
Collections.addAll(args, javaArgs);
ProcessBuilder processBuilder = new ProcessBuilder(args);
這可以被調用為：
runCode(
"-cp",
"C:\\Program Files\\Apache Software Foundation\\Tomcat 8.5\\webapps\\Test\\classes",
"Dog");
另外，不要只打印異常消息。消息本身很少有用。您通常想要打印整個堆棧跟蹤，這樣您將擁有所有信息并且您將確切地知道問題發生的位置：
} catch (IOException ex) {
ex.printStackTrace();
}
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