将Derby db导出为sql文件

Question

I have a derby db in "D:/Dev/workspaces/workspacePro/School-FinMa/school-finma". I want to export it to a this folder "E:/". So I run this:

Runtime.getRuntime().exec("java org.apache.derby.tools.dblook -d 'jdbc:derby:D:/Dev/workspaces/workspacePro/School-FinMa/school-finma' -o 'E:/myDB_DDL.sql'");

But nothing happens, it's like if this code does not exists.

I want a way to export the db to single .sql file, that contains all db generation code + data. How Can I do that from inside Java ??

The project (in eclipse) have derbytools.jar imported.

Answer 1

When you start a new sub process and it doesn't work, you should output the output and error streams. You said there is no output, but I think you didn't get the output stream of the process.

When running a Java sub process you should add the classpath as you would in the command line. In this case you should add derby.jar and derbytools.jar . For a network connection you need derbyclient.jar , too.

You are using Windows. Then don't use single quotation marks.

Here is a simple running example, which prints the output and error streams to the console. Without an error there is no output. But try it with single quotation marks you will see an error message.

In this example the Derby JARs are located at: e:\\derby\\lib .

public static void copyStream(InputStream in, OutputStream out) throws IOException {
  final byte[] buffer = new byte[1024];
  int bytesRead = 0;
  while((bytesRead = in.read(buffer)) != -1) {
    out.write(buffer, 0, bytesRead);
  }
}

public static void main(String[] args) throws IOException, InterruptedException {
  Process process = Runtime.getRuntime().exec( 
    "java -cp e:\\derby\\lib\\derby.jar;e:\\derby\\lib\\derbyclient.jar;e:\\derby\\lib\\derbytools.jar org.apache.derby.tools.dblook -d jdbc:derby:D:/Dev/workspaces/workspacePro/School-FinMa/school-finma -o E:/myDB_DDL.sql");
  final int exitValue = process.waitFor();
  System.out.println("Exit value: " + exitValue);

  System.out.println("Outputstream: ");
  copyStream(process.getInputStream(), System.out);

  System.out.println("Errorstream: ");
  copyStream(process.getErrorStream(), System.out);
}