Refactor the JSON job sample

Issue #3663

spring-batch-samples/README.md

@@ -183,6 +183,20 @@ streaming and Spring OXM marshallers and unmarshallers.
 
 [XML Input Output](./src/main/java/org/springframework/batch/sample/file/xml/README.md)
 
+### JSON Input Output
+
+The goal of this sample is to show how to read and write JSON files:
+
+```json
+[
+  {"isin":"123","quantity":5,"price":10.5,"customer":"foo","id":1,"version":0},
+  {"isin":"456","quantity":10,"price":20.5,"customer":"bar","id":2,"version":0},
+  {"isin":"789","quantity":15,"price":30.5,"customer":"baz","id":3,"version":0}
+]
+```
+
+[JSON Input Output](./src/main/java/org/springframework/batch/sample/file/json/README.md)
+
 ### MultiResource Input Output Job
 
 This sample shows how to use the `MultiResourceItemReader` and `MultiResourceItemWriter`

spring-batch-samples/src/main/java/org/springframework/batch/sample/file/json/JsonJobConfiguration.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2018-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.batch.sample.file.json;
+
+import javax.sql.DataSource;
+
+import org.springframework.batch.core.Job;
+import org.springframework.batch.core.Step;
+import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
+import org.springframework.batch.core.configuration.annotation.StepScope;
+import org.springframework.batch.core.job.builder.JobBuilder;
+import org.springframework.batch.core.repository.JobRepository;
+import org.springframework.batch.core.step.builder.StepBuilder;
+import org.springframework.batch.item.json.GsonJsonObjectReader;
+import org.springframework.batch.item.json.JacksonJsonObjectMarshaller;
+import org.springframework.batch.item.json.JsonFileItemWriter;
+import org.springframework.batch.item.json.JsonItemReader;
+import org.springframework.batch.item.json.builder.JsonFileItemWriterBuilder;
+import org.springframework.batch.item.json.builder.JsonItemReaderBuilder;
+import org.springframework.batch.sample.domain.trade.Trade;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.WritableResource;
+import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
+import org.springframework.jdbc.support.JdbcTransactionManager;
+
+/**
+ * @author Mahmoud Ben Hassine
+ */
+@Configuration
+@EnableBatchProcessing
+public class JsonJobConfiguration {
+
+	@Bean
+	@StepScope
+	public JsonItemReader<Trade> itemReader(@Value("#{jobParameters[inputFile]}") Resource resource) {
+		return new JsonItemReaderBuilder<Trade>().name("tradesJsonItemReader")
+			.resource(resource)
+			.jsonObjectReader(new GsonJsonObjectReader<>(Trade.class))
+			.build();
+	}
+
+	@Bean
+	@StepScope
+	public JsonFileItemWriter<Trade> itemWriter(@Value("#{jobParameters[outputFile]}") WritableResource resource) {
+		return new JsonFileItemWriterBuilder<Trade>().resource(resource)
+			.lineSeparator("\n")
+			.jsonObjectMarshaller(new JacksonJsonObjectMarshaller<>())
+			.name("tradesJsonFileItemWriter")
+			.shouldDeleteIfExists(true)
+			.build();
+	}
+
+	@Bean
+	public Step step(JobRepository jobRepository, JdbcTransactionManager transactionManager,
+			JsonItemReader<Trade> itemReader, JsonFileItemWriter<Trade> itemWriter) {
+		return new StepBuilder("step", jobRepository).<Trade, Trade>chunk(2, transactionManager)
+			.reader(itemReader)
+			.writer(itemWriter)
+			.build();
+	}
+
+	@Bean
+	public Job job(JobRepository jobRepository, Step step) {
+		return new JobBuilder("job", jobRepository).start(step).build();
+	}
+
+	// Infrastructure beans
+
+	@Bean
+	public DataSource dataSource() {
+		return new EmbeddedDatabaseBuilder().addScript("/org/springframework/batch/core/schema-drop-hsqldb.sql")
+			.addScript("/org/springframework/batch/core/schema-hsqldb.sql")
+			.generateUniqueName(true)
+			.build();
+	}
+
+	@Bean
+	public JdbcTransactionManager transactionManager(DataSource dataSource) {
+		return new JdbcTransactionManager(dataSource);
+	}
+
+}

spring-batch-samples/src/main/java/org/springframework/batch/sample/file/json/README.md

@@ -0,0 +1,23 @@
+### Json Input Output Job
+
+## About
+
+The goal of this sample is to show how to read and write JSON files:
+
+```json
+[
+  {"isin":"123","quantity":5,"price":10.5,"customer":"foo","id":1,"version":0},
+  {"isin":"456","quantity":10,"price":20.5,"customer":"bar","id":2,"version":0},
+  {"isin":"789","quantity":15,"price":30.5,"customer":"baz","id":3,"version":0}
+]
+```
+
+## Run the sample
+
+You can run the sample from the command line as following:
+
+```
+$>cd spring-batch-samples
+$>../mvnw -Dtest=JsonFunctionalTests#testJsonReadingAndWriting test
+```
+

spring-batch-samples/src/test/java/org/springframework/batch/sample/file/json/JsonFunctionalTests.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2018-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.batch.sample.file.json;
+
+import java.io.File;
+import java.io.FileInputStream;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.core.ExitStatus;
+import org.springframework.batch.core.Job;
+import org.springframework.batch.core.JobExecution;
+import org.springframework.batch.core.JobParameters;
+import org.springframework.batch.core.JobParametersBuilder;
+import org.springframework.batch.core.launch.JobLauncher;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.util.DigestUtils;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * @author Mahmoud Ben Hassine
+ * @author Glenn Renfro
+ */
+class JsonFunctionalTests {
+
+	public static final String INPUT_FILE = "org/springframework/batch/sample/file/json/data/trades.json";
+
+	public static final String OUTPUT_FILE = "target/test-outputs/trades.json";
+
+	@Test
+	void testJsonReadingAndWriting() throws Exception {
+		ApplicationContext context = new AnnotationConfigApplicationContext(JsonJobConfiguration.class);
+		JobLauncher jobLauncher = context.getBean(JobLauncher.class);
+		Job job = context.getBean(Job.class);
+		JobParameters jobParameters = new JobParametersBuilder().addString("inputFile", INPUT_FILE)
+			.addString("outputFile", "file:./" + OUTPUT_FILE)
+			.toJobParameters();
+		JobExecution jobExecution = jobLauncher.run(job, jobParameters);
+
+		assertEquals(ExitStatus.COMPLETED.getExitCode(), jobExecution.getExitStatus().getExitCode());
+		assertFileEquals(new File("src/main/resources/" + INPUT_FILE), new File(OUTPUT_FILE));
+	}
+
+	private void assertFileEquals(File expected, File actual) throws Exception {
+		String expectedHash = DigestUtils.md5DigestAsHex(new FileInputStream(expected));
+		String actualHash = DigestUtils.md5DigestAsHex(new FileInputStream(actual));
+		assertEquals(expectedHash, actualHash);
+	}
+
+}