Pentaho在同一个jar中启动一个Java程序

Question

We have an organization reports portal for which we use Pentaho. Now the catch is, we need to define one single java Jar in which Pentaho + java files + sql, all are there.

I'm able to execute SQL via Pentaho but I need to execute a class in the same jar via pentaho. This can be done via user Defined Java Class. But how to do it? How to directly import java class in the KTR --> UserDefinedJavaClass.

Folder Structure in jar:

MainJar
|-testJob.kjb
|-testTransformer.ktr
|-com.mainTest.HelloWorld.class

How to call HelloWorld.class from test.ktr?

Answer 1

I haven't been able to get it working with User Defined Java Class step but using the Javascript step instead. You need to copy the JAR to pentaho /lib or /libext folder first. Then in the modified javascript step I just called the class. Here is my step XML

<entry>
  <name>JavaScript</name>
  <description />
  <type>EVAL</type>
  <script>
   var filename=parent_job.getVariable("filename","");
   var filenameClean=filename+"_clean";
   package.CsvCleaner(filename,filenameClean);
  </script>
  <parallel>N</parallel>
  <draw>Y</draw>
  <nr>0</nr>
  <xloc>800</xloc>
  <yloc>1008</yloc>
</entry>

The important part is package.CsvCleaner(filename,filenameClean); actually invokes the constructor of the class with the two parameters and I have added my code in the constructor. You can also call methods and stuff.

I guess the User Defined Java is called in a similar way -add the jar to /lib import the class and use it.

I have one advise though. In my opinion it is better to leave the JAR with the actual ETL code (and not making it part of pentaho by adding it to /lib or /libext) and execute it using a shell command - something like java -jar MyProg.jar Otherwise you will have strange problems:

• having an older version of the Jar in the pentaho installation folder
• harder installation because that jar is not where the kjb and kjt files are
• if pentaho is installed with a different user than the one deploying the ETL he might not have rights to access /lib and /libext folders
• If you have more complicated java code and logic it is better to keep it in the jar instead of in a transformation (having java code in two places is a maintenance hell). So adding the jar to pentaho gives you no benefit over just calling java -jar MyJar.jar