FlatFileItemWriter now uses charset to determine default encoding

It now matches the encoding scheme of FlatFileItemReader

Resolves #1154

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/AbstractFileItemWriter.java

@@ -23,6 +23,7 @@ import java.io.IOException;
 import java.io.Writer;
 import java.nio.channels.Channels;
 import java.nio.channels.FileChannel;
+import java.nio.charset.Charset;
 import java.nio.charset.UnsupportedCharsetException;
 import java.util.List;
 
@@ -59,6 +60,7 @@ import org.springframework.util.Assert;
  * @author Dave Syer
  * @author Michael Minella
  * @author Mahmoud Ben Hassine
+ * @author Glenn Renfro
  * @author Remi Kaeffer
  *
  * @since 4.1
@@ -72,8 +74,8 @@ public abstract class AbstractFileItemWriter<T> extends AbstractItemStreamItemWr
 
 	public static final String DEFAULT_LINE_SEPARATOR = System.getProperty("line.separator");
 
-	// default encoding for writing to output files - set to UTF-8.
-	public static final String DEFAULT_CHARSET = "UTF-8";
+	// default encoding for writing to flat files - set to charset of this Java virtual machine.
+	public static final String DEFAULT_CHARSET = Charset.defaultCharset().name();
 
 	private static final String WRITTEN_STATISTICS_NAME = "written";
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/builder/FlatFileItemWriterBuilderTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2019 the original author or authors.
+ * Copyright 2016-2021 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.
@@ -19,11 +19,13 @@ import java.io.BufferedReader;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.nio.charset.Charset;
 import java.util.Arrays;
 
 import org.junit.Test;
 
 import org.springframework.batch.item.ExecutionContext;
+
 import org.springframework.batch.item.file.FlatFileItemWriter;
 import org.springframework.batch.item.file.transform.PassThroughLineAggregator;
 import org.springframework.core.io.FileSystemResource;
@@ -38,6 +40,7 @@ import static org.junit.Assert.assertTrue;
  * @author Michael Minella
  * @author Mahmoud Ben Hassine
  * @author Drummond Dawson
+ * @author Glenn Renfro
  */
 public class FlatFileItemWriterBuilderTests {
 
@@ -264,6 +267,8 @@ public class FlatFileItemWriterBuilderTests {
 
 		Resource output = new FileSystemResource(File.createTempFile("foo", "txt"));
 
+		String encoding = Charset.defaultCharset().name();
+
 		FlatFileItemWriter<Foo> writer = new FlatFileItemWriterBuilder<Foo>()
 				.name("foo")
 				.resource(output)
@@ -276,14 +281,40 @@ public class FlatFileItemWriterBuilderTests {
 				.lineAggregator(new PassThroughLineAggregator<>())
 				.build();
 
+		validateBuilderFlags(writer, encoding);
+	}
+
+	@Test
+	public void testFlagsWithEncoding() throws Exception {
+
+		Resource output = new FileSystemResource(File.createTempFile("foo", "txt"));
+		String encoding = "UTF-8";
+		FlatFileItemWriter<Foo> writer = new FlatFileItemWriterBuilder<Foo>()
+				.name("foo")
+				.encoding(encoding)
+				.resource(output)
+				.shouldDeleteIfEmpty(true)
+				.shouldDeleteIfExists(false)
+				.saveState(false)
+				.forceSync(true)
+				.append(true)
+				.transactional(false)
+				.lineAggregator(new PassThroughLineAggregator<>())
+				.build();
+		validateBuilderFlags(writer, encoding);
+	}
+
+	private void validateBuilderFlags(FlatFileItemWriter<Foo> writer, String encoding) {
 		assertFalse((Boolean) ReflectionTestUtils.getField(writer, "saveState"));
 		assertTrue((Boolean) ReflectionTestUtils.getField(writer, "append"));
 		assertFalse((Boolean) ReflectionTestUtils.getField(writer, "transactional"));
 		assertTrue((Boolean) ReflectionTestUtils.getField(writer, "shouldDeleteIfEmpty"));
 		assertFalse((Boolean) ReflectionTestUtils.getField(writer, "shouldDeleteIfExists"));
 		assertTrue((Boolean) ReflectionTestUtils.getField(writer, "forceSync"));
+		assertEquals( encoding, ReflectionTestUtils.getField(writer, "encoding"));
 	}
 
+
 	private String readLine(String encoding, Resource outputFile ) throws IOException {
 
 		if (reader == null) {

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/json/builder/JsonFileItemWriterBuilderTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2018 the original author or authors.
+ * Copyright 2018-2021 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.
@@ -17,6 +17,7 @@
 package org.springframework.batch.item.json.builder;
 
 import java.io.File;
+import java.nio.charset.Charset;
 import java.nio.file.Files;
 
 import org.junit.Before;
@@ -36,6 +37,7 @@ import static org.junit.Assert.assertTrue;
 
 /**
  * @author Mahmoud Ben Hassine
+ * @author Glenn Renfro
  */
 public class JsonFileItemWriterBuilderTest {
 
@@ -100,7 +102,45 @@ public class JsonFileItemWriterBuilderTest {
 				.transactional(transactional)
 				.build();
 
-		// then
+		//then
+		validateBuilderFlags(writer, encoding, lineSeparator, headerCallback, footerCallback);
+	}
+
+	@Test
+	public void testJsonFileItemWriterCreationDefaultEncoding() {
+		// given
+		boolean append = true;
+		boolean forceSync = true;
+		boolean transactional = true;
+		boolean shouldDeleteIfEmpty = true;
+		boolean shouldDeleteIfExists = true;
+		String encoding = Charset.defaultCharset().name();
+		String lineSeparator = "#";
+		FlatFileHeaderCallback headerCallback = Mockito.mock(FlatFileHeaderCallback.class);
+		FlatFileFooterCallback footerCallback = Mockito.mock(FlatFileFooterCallback.class);
+
+		// when
+		JsonFileItemWriter<String> writer = new JsonFileItemWriterBuilder<String>()
+				.name("jsonFileItemWriter")
+				.resource(this.resource)
+				.jsonObjectMarshaller(this.jsonObjectMarshaller)
+				.append(append)
+				.forceSync(forceSync)
+				.headerCallback(headerCallback)
+				.footerCallback(footerCallback)
+				.lineSeparator(lineSeparator)
+				.shouldDeleteIfEmpty(shouldDeleteIfEmpty)
+				.shouldDeleteIfExists(shouldDeleteIfExists)
+				.transactional(transactional)
+				.build();
+
+		//then
+		validateBuilderFlags(writer, encoding, lineSeparator, headerCallback, footerCallback);
+	}
+
+	private void validateBuilderFlags(JsonFileItemWriter<String> writer, String encoding,
+			String lineSeparator, FlatFileHeaderCallback headerCallback,
+			FlatFileFooterCallback footerCallback) {
 		assertTrue((Boolean) ReflectionTestUtils.getField(writer, "saveState"));
 		assertTrue((Boolean) ReflectionTestUtils.getField(writer, "append"));
 		assertTrue((Boolean) ReflectionTestUtils.getField(writer, "transactional"));