Fix IsoFormattingDateDataFormatter

The format used the ISO_OFFSET_DATE_TIME is the wrong one and leads to errors
formatting the date. Instead we should have used the ISO_LOCAL_DATE_TIME instead.

This commit fixes that and also includes a bug fix for the XLSX variant as that didn't
use the overridden method. The correct method for this has been overridden now also
formatting the dates/times for that using the ISO_LOCAL_DATE_TIME format.

Tests for different types have been added as well, as to make sure this
keeps working for newer versions.

Closes: #121

spring-batch-excel/src/main/java/org/springframework/batch/extensions/excel/IsoFormattingDateDataFormatter.java

@@ -28,7 +28,7 @@ import org.apache.poi.ss.usermodel.DateUtil;
 import org.apache.poi.ss.usermodel.FormulaEvaluator;
 
 /**
- * Specialized subclass for additionally formatting the date into an ISO date/time.
+ * Specialized subclass for formatting the date into an ISO date/time and ignore the format as given in the Excel file.
  *
  * @author Marten Deinum
  *
@@ -44,6 +44,15 @@ public class IsoFormattingDateDataFormatter extends DataFormatter {
 		super(locale);
 	}
 
+	@Override
+	public String formatRawCellContents(double value, int formatIndex, String formatString, boolean use1904Windowing) {
+		if (DateUtil.isADateFormat(formatIndex, formatString) && DateUtil.isValidExcelDate(value)) {
+			return super.formatRawCellContents(value, formatIndex, "yyyy-MM-ddTHH:mm:ss",
+					use1904Windowing);
+		}
+		return super.formatRawCellContents(value, formatIndex, formatString, use1904Windowing);
+	}
+
 	@Override
 	public String formatCellValue(Cell cell, FormulaEvaluator evaluator, ConditionalFormattingEvaluator cfEvaluator) {
 		if (cell == null) {
@@ -60,7 +69,7 @@ public class IsoFormattingDateDataFormatter extends DataFormatter {
 
 		if (cellType == CellType.NUMERIC && DateUtil.isCellDateFormatted(cell, cfEvaluator)) {
 			LocalDateTime value = cell.getLocalDateTimeCellValue();
-			return (value != null) ? value.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME) : "";
+			return (value != null) ? value.format(DateTimeFormatter.ISO_LOCAL_DATE_TIME) : "";
 		}
 		return super.formatCellValue(cell, evaluator, cfEvaluator);
 	}

spring-batch-excel/src/test/java/org/springframework/batch/extensions/excel/poi/PoiItemReaderTypesTest.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2002-2024 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.extensions.excel.poi;
+
+import java.util.Locale;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.extensions.excel.mapping.PassThroughRowMapper;
+import org.springframework.batch.item.ExecutionContext;
+import org.springframework.core.io.ClassPathResource;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+
+public class PoiItemReaderTypesTest {
+
+	@Test
+	public void shouldBeAbleToReadMultipleTypes() throws Exception {
+		var reader = new PoiItemReader<String[]>();
+		reader.setResource(new ClassPathResource("types.xls"));
+		reader.setRowMapper(new PassThroughRowMapper());
+		reader.setLinesToSkip(1); // Skip header
+		reader.setUserLocale(Locale.US); // Use a Locale to not be dependent on environment
+		reader.afterPropertiesSet();
+
+
+		reader.open(new ExecutionContext());
+
+		var row1 = reader.read();
+		var row2 = reader.read();
+		assertThat(row1).containsExactly("1", "1.0", "5/12/24", "13:14:55", "5/12/24 13:14", "hello world");
+		assertThat(row2).containsExactly("2", "2.5", "8/8/23", "11:12:13", "8/8/23 11:12", "world hello");
+
+	}
+
+	@Test
+	public void shouldBeAbleToReadMultipleTypesWithDatesAsIso() throws Exception {
+		var reader = new PoiItemReader<String[]>();
+		reader.setResource(new ClassPathResource("types.xls"));
+		reader.setRowMapper(new PassThroughRowMapper());
+		reader.setLinesToSkip(1); // Skip header
+		reader.setUserLocale(Locale.US); // Use a Locale to not be dependent on environment
+		reader.setDatesAsIso(true);
+		reader.afterPropertiesSet();
+
+		reader.open(new ExecutionContext());
+
+		var row1 = reader.read();
+		var row2 = reader.read();
+		assertThat(row1).containsExactly("1", "1.0", "2024-05-12T00:00:00", "1899-12-31T13:14:55", "2024-05-12T13:14:55", "hello world");
+		assertThat(row2).containsExactly("2", "2.5", "2023-08-08T00:00:00", "1899-12-31T11:12:13", "2023-08-08T11:12:13", "world hello");
+
+	}
+}

spring-batch-excel/src/test/java/org/springframework/batch/extensions/excel/streaming/StreamingXlsxTypesTest.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2002-2024 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.extensions.excel.streaming;
+
+import java.util.Locale;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.extensions.excel.mapping.PassThroughRowMapper;
+import org.springframework.batch.item.ExecutionContext;
+import org.springframework.core.io.ClassPathResource;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class StreamingXlsxTypesTest {
+
+	@Test
+	public void shouldBeAbleToReadMultipleTypes() throws Exception {
+		var reader = new StreamingXlsxItemReader<String[]>();
+		reader.setResource(new ClassPathResource("types.xlsx"));
+		reader.setRowMapper(new PassThroughRowMapper());
+		reader.setLinesToSkip(1); // Skip header
+		reader.setUserLocale(Locale.US); // Use a Locale to not be dependent on environment
+		reader.afterPropertiesSet();
+
+		reader.open(new ExecutionContext());
+
+		var row1 = reader.read();
+		var row2 = reader.read();
+		assertThat(row1).containsExactly("1", "1.0", "5/12/24", "13:14:55", "5/12/24 13:14", "hello world");
+		assertThat(row2).containsExactly("2", "2.5", "8/8/23", "11:12:13", "8/8/23 11:12", "world hello");
+
+	}
+
+	@Test
+	public void shouldBeAbleToReadMultipleTypesWithDatesAsIso() throws Exception {
+		var reader = new StreamingXlsxItemReader<String[]>();
+		reader.setResource(new ClassPathResource("types.xlsx"));
+		reader.setRowMapper(new PassThroughRowMapper());
+		reader.setLinesToSkip(1); // Skip header
+		reader.setUserLocale(Locale.US); // Use a Locale to not be dependent on environment
+		reader.setDatesAsIso(true);
+		reader.afterPropertiesSet();
+
+		reader.open(new ExecutionContext());
+
+		var row1 = reader.read();
+		var row2 = reader.read();
+		assertThat(row1).containsExactly("1", "1.0", "2024-05-12T00:00:00", "1899-12-31T13:14:55", "2024-05-12T13:14:55", "hello world");
+		assertThat(row2).containsExactly("2", "2.5", "2023-08-08T00:00:00", "1899-12-31T11:12:13", "2023-08-08T11:12:13", "world hello");
+
+	}
+
+}