Add streaming json item writer

Resolves BATCH-2692

spring-batch-samples/src/test/java/org/springframework/batch/sample/JsonSupportIntegrationTests.java

@@ -0,0 +1,129 @@
+/*
+ * Copyright 2018 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
+ *
+ *       http://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;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.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.Step;
+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.launch.JobLauncher;
+import org.springframework.batch.item.json.GsonJsonObjectReader;
+import org.springframework.batch.item.json.JacksonJsonObjectMarshaller;
+import org.springframework.batch.item.json.JsonItemReader;
+import org.springframework.batch.item.json.JsonFileItemWriter;
+import org.springframework.batch.item.json.builder.JsonItemReaderBuilder;
+import org.springframework.batch.item.json.builder.JsonFileItemWriterBuilder;
+import org.springframework.batch.sample.domain.trade.Trade;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.util.DigestUtils;
+
+/**
+ * @author Mahmoud Ben Hassine
+ */
+public class JsonSupportIntegrationTests {
+
+	private static final String INPUT_FILE_DIRECTORY = "src/test/resources/org/springframework/batch/item/json/";
+	private static final String OUTPUT_FILE_DIRECTORY = "build/";
+
+	@Before
+	public void setUp() throws Exception {
+		Files.deleteIfExists(Paths.get("build", "trades.json"));
+	}
+	
+	@Configuration
+	@EnableBatchProcessing
+	public static class JobConfiguration {
+
+		@Autowired
+		private JobBuilderFactory jobs;
+
+		@Autowired
+		private StepBuilderFactory steps;
+
+		@Bean
+		public JsonItemReader<Trade> itemReader() {
+			return new JsonItemReaderBuilder<Trade>()
+					.name("tradesJsonItemReader")
+					.resource(new FileSystemResource(INPUT_FILE_DIRECTORY + "trades.json"))
+					.jsonObjectReader(new GsonJsonObjectReader<>(Trade.class))
+					.build();
+		}
+
+		@Bean
+		public JsonFileItemWriter<Trade> itemWriter() {
+			return new JsonFileItemWriterBuilder<Trade>()
+					.resource(new FileSystemResource(OUTPUT_FILE_DIRECTORY + "trades.json"))
+					.jsonObjectMarshaller(new JacksonJsonObjectMarshaller<>())
+					.name("tradesJsonFileItemWriter")
+					.build();
+		}
+
+		@Bean
+		public Step step() {
+			return steps.get("step")
+					.<Trade, Trade>chunk(2)
+					.reader(itemReader())
+					.writer(itemWriter())
+					.build();
+		}
+
+		@Bean
+		public Job job() {
+			return jobs.get("job")
+					.start(step())
+					.build();
+		}
+	}
+
+	@Test
+	public void testJsonReadingAndWriting() throws Exception {
+		ApplicationContext context = new AnnotationConfigApplicationContext(JobConfiguration.class);
+		JobLauncher jobLauncher = context.getBean(JobLauncher.class);
+		Job job = context.getBean(Job.class);
+		JobExecution jobExecution = jobLauncher.run(job, new JobParameters());
+
+		Assert.assertEquals(ExitStatus.COMPLETED.getExitCode(), jobExecution.getExitStatus().getExitCode());
+		assertFileEquals(
+				new File(INPUT_FILE_DIRECTORY + "trades.json"),
+				new File(OUTPUT_FILE_DIRECTORY + "trades.json"));
+	}
+
+	private void assertFileEquals(File expected, File actual) throws Exception {
+		String expectedHash = DigestUtils.md5DigestAsHex(new FileInputStream(expected));
+		String actualHash = DigestUtils.md5DigestAsHex(new FileInputStream(actual));
+		Assert.assertEquals(expectedHash, actualHash);
+	}
+
+}

spring-batch-samples/src/test/resources/org/springframework/batch/item/json/trades.json

@@ -0,0 +1,5 @@
+[
+ {"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}
+]