java - Spring boot batch MultiResourceItemReader: how to read files using @Value() from jar location

Question

I am trying to get the input files using @Value annotation and set it as a Resource array for MultiResourceItemReader as bellow;

@Value("classpath*:/input/userdata*.csv")
private Resource[] inputFiles;

It is working fine in IDE when I place input files folder in resources folder. The issues is when I run the jar file. It is also working fine if the files are within the jar as in IDE. But it is not picking up when I place the input folder in the same directory of jar file. Here is my Configuration;

        @Value("classpath*:/input/userdata*.csv")
        private Resource[] inputFiles;
        
        @Bean
        public MultiResourceItemReader<UserInfo> multiResourceItemreader() {
            MultiResourceItemReader<UserInfo> reader = new MultiResourceItemReader<>();
            reader.setDelegate(userDataItemReader());
            reader.setResources(inputFiles);
            return reader;
        }

It did not give any error but just the bellow message in console

2021-02-04 16:31:42.959  WARN 15772 --- [           main] o.s.b.item.file.MultiResourceItemReader  : No resources to read. Set strict=true if this should be an error condition.

I am not sure what I am missing here. Tried without classpath prefix in @Value but it gives me bellow exception

java.lang.IllegalArgumentException: Could not resolve resource location pattern [/input/userdata*.csv]

Not sure is there any other way to set the resources for MultiResourceItemReader other than @Value annotation. A help would be greatly appreciated!

Edit:- This is a Spring Boot batch application and here is the directory structure

            apps
            ├── input
            │?? ├── userdata6.csv
            │?? ├── userdata7.csv
            │?? ├── userdata8.csv
            │?? └── userdata9.csv
            └── multisource-batch.jar

I run the jar file as below from the same app directory

java -jar multisource-batch.jar

build.gradle

        plugins {
          id 'org.springframework.boot' version '2.4.2'
          id 'io.spring.dependency-management' version '1.0.11.RELEASE'
          id 'java'
        }

        group = 'com.thomsoncodes.batch'
        version = '0.0.1-SNAPSHOT'
        sourceCompatibility = '1.8'

        repositories {
            mavenCentral()
            maven { url 'https://repo.spring.io/milestone' }
        }

        ext {
            set('springCloudVersion', "2020.0.0")
        }

        dependencies {
            implementation 'org.springframework.boot:spring-boot-starter-batch'
            runtimeOnly 'mysql:mysql-connector-java'
            testImplementation 'org.springframework.boot:spring-boot-starter-test'
            testImplementation 'org.springframework.batch:spring-batch-test'
            
            implementation 'org.projectlombok:lombok:1.18.2'
        }

        dependencyManagement {
            imports {
                mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
            }
        }

        test {
            useJUnitPlatform()
        }

UPDATE:- Finally I got it working!. Even though I removed the Web dependency the spring was still considering this as web. Did a clean build and updated @Value("file:/input/userdata*.csv") as Mahmoud Ben Hassine suggested!

question from:https://stackoverflow.com/questions/66055093/spring-boot-batch-multiresourceitemreader-how-to-read-files-using-value-from

Answer 1

it is not picking up when I place the input folder in the same directory of jar

If you are you running your app with java -jar myapp.jar where the input directory is in the same directory of myapp.jar, then you need to use the file: prefix and not the classpath: prefix.

@Value("file:input/userdata*.csv") should work as it will resolve resources from the relative directory where you launched your JVM.

EDIT: You can find a complete example here.