Spring Batch: Resource must not be null - spring-boot

Question

I am new to spring batch framework. I am making a spring boot program to read from a XML file and store it in the MySQL database.
But the application is throwing the following error.
org.springframework.batch.item.ItemStreamException: Failed to initialize the reader
at org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader.open(AbstractItemCountingItemStreamItemReader.java:153) ~[spring-batch-infrastructure-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader$$FastClassBySpringCGLIB$$ebb633d0.invoke(<generated>) ~[spring-batch-infrastructure-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:771) ~[spring-aop-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749) ~[spring-aop-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:136) ~[spring-aop-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:124) ~[spring-aop-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749) ~[spring-aop-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:691) ~[spring-aop-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.batch.item.xml.StaxEventItemReader$$EnhancerBySpringCGLIB$$1a0f0ba5.open(<generated>) ~[spring-batch-infrastructure-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.batch.item.support.CompositeItemStream.open(CompositeItemStream.java:103) ~[spring-batch-infrastructure-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.batch.core.step.tasklet.TaskletStep.open(TaskletStep.java:311) ~[spring-batch-core-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:205) ~[spring-batch-core-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.batch.core.job.SimpleStepHandler.handleStep(SimpleStepHandler.java:148) ~[spring-batch-core-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.batch.core.job.AbstractJob.handleStep(AbstractJob.java:410) ~[spring-batch-core-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.batch.core.job.SimpleJob.doExecute(SimpleJob.java:136) ~[spring-batch-core-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:319) ~[spring-batch-core-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:147) ~[spring-batch-core-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:50) ~[spring-core-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.batch.core.launch.support.SimpleJobLauncher.run(SimpleJobLauncher.java:140) ~[spring-batch-core-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:344) ~[spring-aop-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:198) ~[spring-aop-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.batch.core.configuration.annotation.SimpleBatchConfiguration$PassthruAdvice.invoke(SimpleBatchConfiguration.java:127) ~[spring-batch-core-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at com.sun.proxy.$Proxy39.run(Unknown Source) ~[na:na]
at org.springframework.boot.autoconfigure.batch.JobLauncherApplicationRunner.execute(JobLauncherApplicationRunner.java:199) ~[spring-boot-autoconfigure-2.3.2.RELEASE.jar:2.3.2.RELEASE]
at org.springframework.boot.autoconfigure.batch.JobLauncherApplicationRunner.executeLocalJobs(JobLauncherApplicationRunner.java:173) ~[spring-boot-autoconfigure-2.3.2.RELEASE.jar:2.3.2.RELEASE]
at org.springframework.boot.autoconfigure.batch.JobLauncherApplicationRunner.launchJobFromProperties(JobLauncherApplicationRunner.java:160) ~[spring-boot-autoconfigure-2.3.2.RELEASE.jar:2.3.2.RELEASE]
at org.springframework.boot.autoconfigure.batch.JobLauncherApplicationRunner.run(JobLauncherApplicationRunner.java:155) ~[spring-boot-autoconfigure-2.3.2.RELEASE.jar:2.3.2.RELEASE]
at org.springframework.boot.autoconfigure.batch.JobLauncherApplicationRunner.run(JobLauncherApplicationRunner.java:150) ~[spring-boot-autoconfigure-2.3.2.RELEASE.jar:2.3.2.RELEASE]
at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:786) ~[spring-boot-2.3.2.RELEASE.jar:2.3.2.RELEASE]
at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:776) ~[spring-boot-2.3.2.RELEASE.jar:2.3.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:322) ~[spring-boot-2.3.2.RELEASE.jar:2.3.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1237) ~[spring-boot-2.3.2.RELEASE.jar:2.3.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.3.2.RELEASE.jar:2.3.2.RELEASE]
at com.swt.helloworld.HelloworldApplication.main(HelloworldApplication.java:41) ~[classes/:na]
Caused by: java.lang.IllegalArgumentException: The Resource must not be null.
at org.springframework.util.Assert.notNull(Assert.java:201) ~[spring-core-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.batch.item.xml.StaxEventItemReader.doOpen(StaxEventItemReader.java:205) ~[spring-batch-infrastructure-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader.open(AbstractItemCountingItemStreamItemReader.java:150) ~[spring-batch-infrastructure-4.2.4.RELEASE.jar:4.2.4.RELEASE]
... 43 common frames omitted
I am not able to understand why the resource is null error is coming.I have also attached my BatchConfiguration.java file below:
package com.swt.helloworld.config;
import com.swt.helloworld.model.Product;
import com.swt.helloworld.writer.ConsoleItemWriter;
import com.swt.helloworld.listener.HwJobExecutionListener;
import com.swt.helloworld.listener.HwStepExecutionListener;
import com.swt.helloworld.processor.InMemeItemProcessor;
import com.swt.helloworld.reader.InMemReader;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.StepContribution;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepScope;
import org.springframework.batch.core.launch.support.RunIdIncrementer;
import org.springframework.batch.core.scope.context.ChunkContext;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.item.file.FlatFileItemReader;
import org.springframework.batch.item.file.mapping.BeanWrapperFieldSetMapper;
import org.springframework.batch.item.file.mapping.DefaultLineMapper;
import org.springframework.batch.item.file.transform.DelimitedLineTokenizer;
import org.springframework.batch.item.file.transform.LineTokenizer;
import org.springframework.batch.item.xml.StaxEventItemReader;
import org.springframework.batch.repeat.RepeatStatus;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.FileSystemResource;
import org.springframework.oxm.jaxb.Jaxb2Marshaller;
#EnableBatchProcessing
#Configuration
public class BatchCondifguration {
#Autowired
private JobBuilderFactory jobs;
#Autowired
private StepBuilderFactory steps;
#Autowired
private HwJobExecutionListener hwJobExecutionListener;
#Autowired
private HwStepExecutionListener hwStepExecutionListener;
#Autowired
private InMemeItemProcessor inMemeItemProcessor;
public Tasklet helloWorldTasklet(){
return (new Tasklet() {
#Override
public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception {
System.out.println("Hello world " );
return RepeatStatus.FINISHED;
}
});
}
#Bean
public Step step1(){
return steps.get("step1")
.listener(hwStepExecutionListener)
.tasklet(helloWorldTasklet())
.build();
}
#Bean
public InMemReader reader(){
return new InMemReader();
}
#StepScope
#Bean
public StaxEventItemReader xmlItemReader(
#Value( "#{jobParameters['fileInput']}" )
FileSystemResource inputFile
){
// where to read the xml file
StaxEventItemReader reader = new StaxEventItemReader();
reader.setResource(inputFile);
//need to let reader to know which tags describe the domain object
reader.setFragmentRootElementName("product");
// tell reader how to parse XML and which domain object to be mapped
reader.setUnmarshaller(new Jaxb2Marshaller(){
{
setClassesToBeBound(Product.class);
}
});
return reader;
}
#StepScope
#Bean
public FlatFileItemReader flatFileItemReader(
#Value( "#{jobParameters['fileInput']}" )
FileSystemResource inputFile ){
FlatFileItemReader reader = new FlatFileItemReader();
// step 1 let reader know where is the file
reader.setResource( inputFile );
//create the line Mapper
reader.setLineMapper(
new DefaultLineMapper<Product>(){
{
setLineTokenizer( new DelimitedLineTokenizer() {
{
setNames( new String[]{"prodId","productName","prodDesc","price","unit"});
setDelimiter("|");
}
});
setFieldSetMapper( new BeanWrapperFieldSetMapper<Product>(){
{
setTargetType(Product.class);
}
});
}
}
);
//step 3 tell reader to skip the header
reader.setLinesToSkip(1);
return reader;
}
#Bean
public Step step2(){
return steps.get("step2").
<Integer,Integer>chunk(3)
// .reader(flatFileItemReader( null ))
.reader(xmlItemReader(null))
.writer(new ConsoleItemWriter())
.build();
}
#Bean
public Job helloWorldJob(){
return jobs.get("helloWorldJob")
.incrementer(new RunIdIncrementer())
.listener(hwJobExecutionListener)
.start(step1())
.next(step2())
.build();
}
}

Answer 1

Following the stack trace, I think you need to check your "job parameter" named 'fileInput'. Enter the file path in your program parameter 'fileInput'.
Perhaps it works adding this part in you parameter when you run your batch application:
fileInput=/path/your/input/file
See futher at the Spring document.