在Eclipse中进行“ Maven安装”时出错：软件包net.sf.jasperreports.engine不存在

Question

I am trying to get started with Jasper Reports with Spring Batch.

Work Environment: RAD 7.5 (so eclipse!), Maven

I have a simplest of all Spring Batch program with one job having one tasklet, which does nothing but prints HELLO WORLD.

This runs fine.

After this - I copy jasper reports jar file in the lib folder of my project. Right click on the project -> Go to properties -> Build Path -> Add Jar Files -> Select jasper report jar and click ok.

Fine till now.

Now in my tasklet program, I am just adding the below line:

JasperReport jasperReport;

Since I am declaring a variable of type JasperReport, eclipse shouts about importing the class.

I click on the error bubble (the red bubble with cross) which eclipse shows, and it lists the correct class from above jar which I added to the class path. I select the import recommendation and error is gone.

Now, I am saving the file -> Right click on the project -> Run As -> Maven-Install and thats it:

Maven complains:

Compilation failure
C:\Nikunj\Sandbox\Reporting\src\main\java\com\in\nik\example\util\GenerateReportTasklet.java:[12,35] package net.sf.jasperreports.engine does not exist

C:\Nikunj\Sandbox\Reporting\src\main\java\com\in\nik\example\util\GenerateReportTasklet.java:[25,8] cannot find symbol
symbol  : class JasperReport
location: class com.in.nik.example.util.GenerateReportTasklet

Checked 100 times. The package is there in the jar. The class is there in the jar. If its not there, won't eclipse show error. Its not showing. Means its there.

My GenerateReportTasklet is:

package com.hsbc.us.pb.custody.util;

import net.sf.jasperreports.engine.JasperReport;

import org.springframework.batch.core.StepContribution;
import org.springframework.batch.core.scope.context.ChunkContext;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.repeat.RepeatStatus;


public class GenerateReportTasklet implements Tasklet {

    public RepeatStatus execute(final StepContribution arg0, final ChunkContext arg1) throws Exception {

        JasperReport jasperReport;

        System.out.println("Hello Report!");

        return null;
    }

}

I am out of my mind figuring out what I am missing.

Please do not advice to add the jar as dependency in my POM.xml I can easily do that.

But I know what I am trying to do above should work and its not working. I want to get to the root of that.

Any ideas ?

I know it does not matter but I have downloaded the jar from java2s.com:

http://www.java2s.com/Code/Jar/JKL/Downloadjasperreportsjar.htm

Thanks for reading!!

Answer 1

When you compile with Eclipse, then Eclipse will build a classpath for the compilation. If you tell Eclipse you need a JAR, then Eclipse will include that JAR in the compile classpath and your compile will work.

The same thing happens with Maven, except that the way to tell Maven that you need that JAR is by adding it as a dependency in the POM.

You don't expect Eclipse to know (without you telling it) that you need a certain JAR. Why do you expect anything different of Maven?

Note: Maven, which is an IDE-independent tool, doesn't know about your Eclipse project configuration - though you can do the reverse and make Eclipse configure its classpath from the POM-declared dependencies.