BAEL-5202: Add excel multiline text (#11366)

* BAEL-5202: Add excel multiline text

* BAEL-5202: Reformat code and rename ExcelMultilineText for consistency with unit test

* Cleanup and formatting

apache-poi/src/main/java/com/baeldung/poi/excel/multilinetext/MultilineText.java

@@ -0,0 +1,18 @@
+package com.baeldung.poi.excel.multilinetext;
+
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.CellStyle;
+import org.apache.poi.ss.usermodel.Row;
+
+public class MultilineText {
+    public void formatMultilineText(Cell cell, int cellNumber) {
+        cell.getRow()
+            .setHeightInPoints(cell.getSheet()
+                .getDefaultRowHeightInPoints() * 2);
+        CellStyle cellStyle = cell.getSheet()
+            .getWorkbook()
+            .createCellStyle();
+        cellStyle.setWrapText(true);
+        cell.setCellStyle(cellStyle);
+    }
+}

apache-poi/src/test/java/com/baeldung/poi/excel/multilinetext/MultilineTextUnitTest.java

@@ -0,0 +1,69 @@
+package com.baeldung.poi.excel.multilinetext;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.nio.file.Paths;
+
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.DataFormatter;
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
+import org.junit.Before;
+import org.junit.Test;
+
+public class MultilineTextUnitTest {
+    private static String FILE_NAME = "com/baeldung/poi/excel/multilinetext/MultilineTextTest.xlsx";
+    private static final String NEW_FILE_NAME = "MultilineTextTest_output.xlsx";
+    private static final int STRING_ROW_INDEX = 1;
+    private static final int STRING_CELL_INDEX = 0;
+
+    private String fileLocation;
+
+    @Before
+    public void setup() throws IOException, URISyntaxException {
+        fileLocation = Paths.get(ClassLoader.getSystemResource(FILE_NAME)
+            .toURI())
+            .toString();
+    }
+
+    @Test
+    public void givenMultilineTextCell_whenFormated_thenMultilineTextVisible() throws IOException {
+        Workbook workbook = new XSSFWorkbook(fileLocation);
+        Sheet sheet = workbook.getSheetAt(0);
+        sheet.createRow(STRING_ROW_INDEX);
+        Row row = sheet.getRow(STRING_ROW_INDEX);
+        Cell cell = row.createCell(STRING_CELL_INDEX);
+
+        cell.setCellValue("Hello \n world!");
+        MultilineText multilineText = new MultilineText();
+        multilineText.formatMultilineText(cell, STRING_CELL_INDEX);
+
+        FileOutputStream outputStream = new FileOutputStream(NEW_FILE_NAME);
+        workbook.write(outputStream);
+        outputStream.close();
+
+        File file = new File(NEW_FILE_NAME);
+        FileInputStream fileInputStream = new FileInputStream(file);
+        Workbook testWorkbook = new XSSFWorkbook(fileInputStream);
+        assertTrue(row.getHeightInPoints() == testWorkbook.getSheetAt(0)
+            .getRow(STRING_ROW_INDEX)
+            .getHeightInPoints());
+        DataFormatter formatter = new DataFormatter();
+        assertEquals("Hello \n world!", formatter.formatCellValue(testWorkbook.getSheetAt(0)
+            .getRow(STRING_ROW_INDEX)
+            .getCell(STRING_CELL_INDEX)));
+        testWorkbook.close();
+        fileInputStream.close();
+        file.delete();
+
+        workbook.close();
+    }
+}