Java POI creates an excel table and reads the excel table information

Office 2007 and above

Prerequisites, import jar package

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.apache.poi</groupId>
        <artifactId>poi</artifactId>
        <version>3.17</version>
    </dependency>
    <dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.17</version>

Create excel sheet

public class WriteExcel07 {
       @Test  
        public  void writeExcel() throws IOException{  
             // Create workbook   
            XSSFWorkbook workBook = new XSSFWorkbook();  
             // Create worksheet   
            XSSFSheet sheet = workBook.createSheet("helloWorld" );  
             // Create row   
            XSSFRow row = sheet.createRow(0 );  
             // Create a cell, operate the third row and third column   
            XSSFCell cell = row.createCell(0 , CellType.STRING);  
            cell.setCellValue("helloWorld");  
              
            FileOutputStream outputStream = new FileOutputStream(new File("C:\\Users\\shay_deng\\Desktop\\test.xlsx"));  
            workBook.write(outputStream);  
              
            workBook.close(); // Remember to close the workbook   
        }  
}

Read excel table information

public class ReadExcel07 {
    @Test  
    public void readExcel() throws IOException{  
        FileInputStream inputStream = new FileInputStream( new File("C:\\Users\\shay_deng\\Desktop\\test.xlsx" ));  
         // read workbook   
        XSSFWorkbook workBook = new XSSFWorkbook(inputStream);  
         // read work Sheet   
        XSSFSheet sheet = workBook.getSheetAt(0 );  
         // read row   
        XSSFRow row = sheet.getRow(0 );  
         // read cell   
        XSSFCell cell = row.getCell(0 );  
        String value = cell.getStringCellValue();  
          
        System.out.println(value);  
          
        inputStream.close(); // Close the workbook   
        workBook.close();  
    }
}

1. Merge cells, belong to worksheets, create independently, apply to worksheets

2. Styles, belonging to worksheets, created by workbooks, applied to cells

3. Fonts, belonging to worksheets, created by workbooks, applied to styles

4. To set the background color, be sure to set the color fill mode first

public class TestPOIExcelStyle {
     @Test  
        public  void testExcelStyle() throws IOException{  
             // 1. Create workbook   
            HSSFWorkbook workBook = new HSSFWorkbook ();  
              
            // Create merged cell object   
            CellRangeAddress rangeAddress = new CellRangeAddress(2, 2, 2, 4 );  
             // Create style   
            HSSFCellStyle style = workBook.createCellStyle();  
            style.setAlignment (HorizontalAlignment.CENTER);  
            style.setVerticalAlignment(VerticalAlignment.CENTER);  
            // Create font   
            HSSFFont font = workBook.createFont();  
            font.setFontHeightInPoints(( short ) 16 );  
             // font.setFontHeight((short)320); The effect is the same as above. Use this method to set the size, the value should be set to font size * 20 times, see the API document   
            font.setColor(HSSFColor.GREEN.index);  
            font.setBold(true);  
            style.setFont(font);  
            // Set the background   
            style.setFillPattern(FillPatternType.SOLID_FOREGROUND);  
            style.setFillForegroundColor(HSSFColor.RED.index);  
              
            // 2. Create worksheet   
            HSSFSheet sheet = workBook.createSheet("helloWorld" );  
             // Add merge area   
            sheet.addMergedRegion(rangeAddress);  
              
            // 3. Create row   
            HSSFRow row = sheet.createRow(2 );  
             // 4. Create cell   
            HSSFCell cell = row.createCell(2 );  
            cell.setCellValue("helloWorld");  
            cell.setCellStyle(style);  
              
            //输出  
            FileOutputStream outputStream = new FileOutputStream(new File("C:\\Users\\shay_deng\\Desktop\\test.xls"));  
            workBook.write(outputStream);  
              
            workBook.close();  
            outputStream.close();  
        }  
}