process.exec 未返回正确的代码

发布于 2024-09-14 17:53:56 字数 1264 浏览 10 评论 0原文

我有一个 Java 程序，代码如下：

public class Test1 {
public static void main(String args[]) throws InterruptedException,
        IOException {
    String cmd = "cmd /c start test.bat";
    Process p = Runtime.getRuntime().exec(cmd); 
    InputStream stderr = process.getErrorStream();
    InputStreamReader isr = new InputStreamReader(stderr);
    BufferedReader br = new BufferedReader(isr);
    String line = null;

    while ((line = br.readLine()) != null){
        System.out.println(line);}

      p.waitFor(); 
      int exitVal = p.exitValue(); 
      System.out.println(exitVal);

} test.bat

执行另一个程序，其代码如下：

public class ConnectionTest {

public Connection getConn throws SQLException{
      Connection conn = null;
      Statement st = null;
      ResultSet rs = null;
      String driverName = "com.ibm.db2.jcc.DB2Driver22222";
        try {
                Class.forName(driverName).newInstance();
            } catch (Exception e) {
                e.printStackTrace();

                System.exit(1);
                                }

;;;; ;;;; ;;; ;;;

但是从Test1来看，退出值始终为0。怎么，当批处理执行时，它会运行 ConnectionTest 类将出现异常，因为它找不到 DB2Driver22222。

谁能向我解释为什么我没有收到正确的错误代码或任何错误消息。

原文

I have a Java program with code:

public class Test1 {
public static void main(String args[]) throws InterruptedException,
        IOException {
    String cmd = "cmd /c start test.bat";
    Process p = Runtime.getRuntime().exec(cmd); 
    InputStream stderr = process.getErrorStream();
    InputStreamReader isr = new InputStreamReader(stderr);
    BufferedReader br = new BufferedReader(isr);
    String line = null;

    while ((line = br.readLine()) != null){
        System.out.println(line);}

      p.waitFor(); 
      int exitVal = p.exitValue(); 
      System.out.println(exitVal);

}
}

test.bat executes another program which has the folowing code:

public class ConnectionTest {

public Connection getConn throws SQLException{
      Connection conn = null;
      Statement st = null;
      ResultSet rs = null;
      String driverName = "com.ibm.db2.jcc.DB2Driver22222";
        try {
                Class.forName(driverName).newInstance();
            } catch (Exception e) {
                e.printStackTrace();

                System.exit(1);
                                }

;;;;
;;;;
;;;
;;;

But from the Test1, the exit value is always 0. HOw come, when the batch is executed, it will run the
ConnectionTest class and it will get exception as it will not find DB2Driver22222.

Can anybody explain to me why I am not getting correct error code nor any error messages.

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于我来说 2024-09-21 17:53:56

问题是您收到的是 start 命令的返回代码，而不是收到 start 命令执行的内容。尽管 start 可能会看到 test.bat 退出并显示代码 1，但 start 本身会成功退出 (0)。直接执行 .bat：

String cmd = "test.bat";

The problem is that you are recieving the return code of the start command, and not what the start command executes. Though start may see test.bat exit with code 1, start itself exits success (0). Execute the .bat directly instead: