Apache POI - 单元格

您在电子表格中输入的任何数据始终存储在单元格中。 我们使用行和列的标签来识别一个单元格。 本章介绍如何使用 Java 编程处理电子表格中单元格中的数据。

创建一个单元格

您需要在创建单元格之前创建一行。 一行不过是单元格的集合。

以下代码段用于创建单元格。

//create new workbook
XSSFWorkbook workbook = new XSSFWorkbook(); 

//create spreadsheet with a name
XSSFSheet spreadsheet = workbook.createSheet("new sheet");

//create first row on a created spreadsheet
XSSFRow row = spreadsheet.createRow(0);

//create first cell on created row
XSSFCell cell = row.createCell(0);

单元格类型

单元格类型指定单元格是否可以包含字符串、数值或公式。 字符串单元格不能保存数值，数字单元格不能保存字符串。

以下代码用于在电子表格中创建不同类型的单元格。

import java.io.File;
import java.io.FileOutputStream;
import java.util.Date;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class TypesofCells {
   public static void main(String[] args)throws Exception {
      XSSFWorkbook workbook = new XSSFWorkbook(); 
      XSSFSheet spreadsheet = workbook.createSheet("cell types");
      
      XSSFRow row = spreadsheet.createRow((short) 2);
      row.createCell(0).setCellValue("Type of Cell");
      row.createCell(1).setCellValue("cell value");
      
      row = spreadsheet.createRow((short) 3);
      row.createCell(0).setCellValue("set cell type BLANK");
      row.createCell(1);
      
      row = spreadsheet.createRow((short) 4);
      row.createCell(0).setCellValue("set cell type BOOLEAN");
      row.createCell(1).setCellValue(true);
      
      row = spreadsheet.createRow((short) 5);
      row.createCell(0).setCellValue("set cell type date");
      row.createCell(1).setCellValue(new Date());
      
      row = spreadsheet.createRow((short) 6);
      row.createCell(0).setCellValue("set cell type numeric");
      row.createCell(1).setCellValue(20 );
      
      row = spreadsheet.createRow((short) 7);
      row.createCell(0).setCellValue("set cell type string");
      row.createCell(1).setCellValue("A String");
      
      FileOutputStream out = new FileOutputStream(new File("typesofcells.xlsx"));
      workbook.write(out);
      out.close();
      System.out.println("typesofcells.xlsx written successfully");
   }
}

将以上代码保存在一个名为TypesofCells.java的文件中，在命令提示符下编译并执行如下 −

$javac TypesofCells.java
$java TypesofCells

如果您的系统配置了 POI 库，那么它将编译并执行以在您的当前目录中生成一个名为 typesofcells.xlsx 的 Excel 文件并显示以下输出。

typesofcells.xlsx written successfully

typesofcells.xlsx 文件如下所示 −

单元格样式

您可以在这里学习如何设置单元格格式并应用不同的样式，例如合并相邻单元格、添加边框、设置单元格对齐方式和填充颜色。

以下代码用于使用 Java 编程将不同的样式应用于单元格。

import java.io.File;
import java.io.FileOutputStream;

import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.ss.usermodel.BorderStyle;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import org.apache.poi.ss.usermodel.IndexedColors;
import org.apache.poi.ss.usermodel.VerticalAlignment;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFColor;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.apache.poi.ss.usermodel.Color;
import org.apache.poi.ss.usermodel.FillPatternType;

public class CellStyle {
   public static void main(String[] args)throws Exception {
      XSSFWorkbook workbook = new XSSFWorkbook(); 
      XSSFSheet spreadsheet = workbook.createSheet("cellstyle");
      XSSFRow row = spreadsheet.createRow((short) 1);
      row.setHeight((short) 800);
      XSSFCell cell = (XSSFCell) row.createCell((short) 1);
      cell.setCellValue("test of merging");

      //MEARGING CELLS 
      //this statement for merging cells

      spreadsheet.addMergedRegion(
         new CellRangeAddress(
            1, //first row (0-based)
            1, //last row (0-based)
            1, //first column (0-based)
            4 //last column (0-based)
         )
      );
      
      //CELL Alignment
      row = spreadsheet.createRow(5); 
      cell = (XSSFCell) row.createCell(0);
      row.setHeight((short) 800);
      
      // Top Left alignment 
      XSSFCellStyle style1 = workbook.createCellStyle();
      spreadsheet.setColumnWidth(0, 8000);
      style1.setAlignment(HorizontalAlignment.LEFT);
      style1.setVerticalAlignment(VerticalAlignment.TOP);
      cell.setCellValue("Top Left");
      cell.setCellStyle(style1);
      row = spreadsheet.createRow(6); 
      cell = (XSSFCell) row.createCell(1);
      row.setHeight((short) 800);
      
      // Center Align Cell Contents 
      XSSFCellStyle style2 = workbook.createCellStyle();
      style2.setAlignment(HorizontalAlignment.CENTER);
      style2.setVerticalAlignment(VerticalAlignment.CENTER);
      cell.setCellValue("Center Aligned"); 
      cell.setCellStyle(style2);
      row = spreadsheet.createRow(7); 
      cell = (XSSFCell) row.createCell(2);
      row.setHeight((short) 800);
      
      // Bottom Right alignment 
      XSSFCellStyle style3 = workbook.createCellStyle();
      style3.setAlignment(HorizontalAlignment.RIGHT);
      style3.setVerticalAlignment(VerticalAlignment.BOTTOM);
      cell.setCellValue("Bottom Right");
      cell.setCellStyle(style3);
      row = spreadsheet.createRow(8);
      cell = (XSSFCell) row.createCell(3);
      
      // Justified Alignment 
      XSSFCellStyle style4 = workbook.createCellStyle();
      style4.setAlignment(HorizontalAlignment.JUSTIFY);
      style4.setVerticalAlignment(VerticalAlignment.JUSTIFY);
      cell.setCellValue("Contents are Justified in Alignment"); 
      cell.setCellStyle(style4);
      
      //CELL BORDER
      row = spreadsheet.createRow((short) 10);
      row.setHeight((short) 800);
      cell = (XSSFCell) row.createCell((short) 1);
      cell.setCellValue("BORDER");
      
      XSSFCellStyle style5 = workbook.createCellStyle();
      style5.setBorderBottom(BorderStyle.THICK);
      style5.setBottomBorderColor(IndexedColors.BLUE.getIndex());
      style5.setBorderLeft(BorderStyle.DOUBLE);
      style5.setLeftBorderColor(IndexedColors.GREEN.getIndex());
      style5.setBorderRight(BorderStyle.HAIR);
      style5.setRightBorderColor(IndexedColors.RED.getIndex());
      style5.setBorderTop(BorderStyle.DOTTED);
      style5.setTopBorderColor(IndexedColors.CORAL.getIndex());
      cell.setCellStyle(style5);
      
      //Fill Colors
      //background color
      row = spreadsheet.createRow((short) 10 );
      cell = (XSSFCell) row.createCell((short) 1);
      
      XSSFCellStyle style6 = workbook.createCellStyle();
      style6.setFillBackgroundColor(IndexedColors.LIME.index);
      style6.setFillPattern(FillPatternType.LESS_DOTS);
      style6.setAlignment(HorizontalAlignment.FILL);
      spreadsheet.setColumnWidth(1,8000);
      cell.setCellValue("FILL BACKGROUNG/FILL PATTERN");
      cell.setCellStyle(style6);
      
      //Foreground color
      row = spreadsheet.createRow((short) 12);
      cell = (XSSFCell) row.createCell((short) 1);
      
      XSSFCellStyle style7 = workbook.createCellStyle();
      style7.setFillForegroundColor(IndexedColors.BLUE.index);
      style7.setFillPattern( FillPatternType.LESS_DOTS);
      style7.setAlignment(HorizontalAlignment.FILL);
      cell.setCellValue("FILL FOREGROUND/FILL PATTERN");
      cell.setCellStyle(style7);

      FileOutputStream out = new FileOutputStream(new File("cellstyle.xlsx"));
      workbook.write(out);
      out.close();
      System.out.println("cellstyle.xlsx written successfully");
   }
}

将上述代码保存在一个名为CellStyle.java的文件中，在命令提示符下编译并执行如下 −

$javac CellStyle.java
$java CellStyle

它将在您的当前目录中生成一个名为 cellstyle.xlsx 的 Excel 文件并显示以下输出。

cellstyle.xlsx written successfully