hadoop - How to use Sqoop in Java Program?

Question

I know how to use sqoop through command line. But dont know how to call sqoop command using java programs . Can anyone give some code view?

Answer 1

You can run sqoop from inside your java code by including the sqoop jar in your classpath and calling the Sqoop.runTool() method. You would have to create the required parameters to sqoop programmatically as if it were the command line (e.g. --connect etc.).

Please pay attention to the following:

• Make sure that the sqoop tool name (e.g. import/export etc.) is the first parameter.
• Pay attention to classpath ordering - The execution might fail because sqoop requires version X of a library and you use a different version. Ensure that the libraries that sqoop requires are not overshadowed by your own dependencies. I've encountered such a problem with commons-io (sqoop requires v1.4) and had a NoSuchMethod exception since I was using commons-io v1.2.
• Each argument needs to be on a separate array element. For example, "--connect jdbc:mysql:..." should be passed as two separate elements in the array, not one.
• The sqoop parser knows how to accept double-quoted parameters, so use double quotes if you need to (I suggest always). The only exception is the fields-delimited-by parameter which expects a single char, so don't double-quote it.
• I'd suggest splitting the command-line-arguments creation logic and the actual execution so your logic can be tested properly without actually running the tool.
• It would be better to use the --hadoop-home parameter, in order to prevent dependency on the environment.
• The advantage of Sqoop.runTool() as opposed to Sqoop.Main() is the fact that runTool() return the error code of the execution.

Hope that helps.

final int ret = Sqoop.runTool(new String[] { ... });
if (ret != 0) {
  throw new RuntimeException("Sqoop failed - return code " + Integer.toString(ret));
}

RL