java用org.apache.poi包操作excel

1.Jakarta POI 是apache的子项目，目标是处理ol2对象。它提供了一组Windows文档操作的Java API。

2.EXCEL 结构
HSSFWorkbook excell 文档对象介绍
HSSFSheet excell的表单
HSSFRow excell的行
HSSFCell excell的格子单元
HSSFFont excell字体
HSSFName 名称
HSSFDataFormat 日期格式
在poi1.7中才有以下2项：
HSSFHeader sheet头
HSSFFooter sheet尾
和这个样式
HSSFCellStyle cell样式
辅助操作包括
HSSFDateUtil 日期
HSSFPrintSetup 打印
HSSFErrorConstants 错误信息表

3.简单的用法

创建Excel

import java.io.FileOutputStream;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public class NewWorkbook {

    public static String outputFile = "C:/test1.xls";
    public static void main(String[] args) {

        try {
            HSSFWorkbook wb = new HSSFWorkbook();//create new HSSFWorkbook object
            FileOutputStream fileOut = new FileOutputStream(outputFile);
            wb.write(fileOut);//Workbook-->test1.xls
            fileOut.flush();
            fileOut.close();
            System.out.println("The file has been created.");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

简单的Excel写操作

import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Date;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFDataFormat;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public class CreateCells {

    public static String fileTobewrite = "C:/test1.xls";
    public static void main(String[] args) throws IOException {
        try {
            HSSFWorkbook wb = new HSSFWorkbook();//create new HSSFWorkbook object
            HSSFSheet sheet = wb.createSheet("new sheet");// create new sheet object
            //Create a row and put some cells in it. Rows are 0.
            HSSFRow row = sheet.createRow(0);//create new row
            //Create a cell and put a value in it.
            HSSFCell cell = row.createCell(0);//create new cell
            cell.setCellValue(1);//setting the cell value

            //do it on one line
            row.createCell(1).setCellValue(1.2);
            row.createCell(2).setCellValue("test");
            row.createCell(3).setCellValue(true);
            HSSFCellStyle cellStyle = wb.createCellStyle();//new cell style
            cellStyle.setDataFormat(HSSFDataFormat.getBuiltinFormat("m/d/yy h:mm"));// set date style
            HSSFCell dcell = row.createCell(4);//create new cell
            dcell.setCellValue(new Date());
            dcell.setCellStyle(cellStyle);
            HSSFCell csCell = row.createCell(5);
            csCell.setCellType(HSSFCell.ENCODING_UTF_16);
            csCell.setCellValue("中文测试_Chinese Words Test");//set cell code

            row.createCell(6).setCellType(HSSFCell.CELL_TYPE_ERROR);

            //write the output to a file
            FileOutputStream fileOut = new FileOutputStream(fileTobewrite);
            wb.write(fileOut);
            fileOut.flush();
            fileOut.close();
            System.out.println("The cells have been added.");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


}

简单的Excel读操作

import java.io.FileInputStream;
import java.text.DateFormat;
import java.text.SimpleDateFormat;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFDateUtil;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public class ReadExcel {
    public static String fileTobeRead = "C:/test1.xls";
    public static String getCellValue(HSSFCell cell){
        String value = null;
        if (cell != null)
        {
            //get the type of the cell
            int cellType = cell.getCellType();
            switch (cellType)
            {
            //""
            case HSSFCell.CELL_TYPE_BLANK :
                value = "";
                break;
            //Boolean
            case HSSFCell.CELL_TYPE_BOOLEAN :
                value = cell.getBooleanCellValue() ? "TRUE" : "FALSE";
                break;
            //Error
            case HSSFCell.CELL_TYPE_ERROR :
                value = "ERR-" + cell.getErrorCellValue();
                break;
            //Formula
            case HSSFCell.CELL_TYPE_FORMULA :
                value = cell.getCellFormula();
                break;
            //Numeric
            case HSSFCell.CELL_TYPE_NUMERIC :
                //Date
                if (HSSFDateUtil.isCellDateFormatted(cell))
                {
                    //change to "yyyy-MM-dd"
                    DateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
                    value = sdf.format(cell.getDateCellValue());
                }
                //Number
                else
                {
                    value = cell.getNumericCellValue() + "";
                }
                break;
            //String
            case HSSFCell.CELL_TYPE_STRING :
                value = cell.getStringCellValue();
                break;
            //Other
            default :
                value = "Unknown Cell Type:"  + cell.getCellType();
            }
        }
        return value;

    }

    public static void main(String[] args) {
        try {
            HSSFWorkbook wb = new HSSFWorkbook(new FileInputStream(fileTobeRead));

            HSSFSheet sheet = wb.getSheet("new sheet");
            //getSheetAt(int index) first sheet index is 0.
            int rowNum = sheet.getPhysicalNumberOfRows();
            int cellNum;
            System.out.println("Row number is " + rowNum);
            HSSFRow row;
            HSSFCell cell;
            for(int i=0;i<sheet.getPhysicalNumberOfRows();i++){

                row = sheet.getRow(i);
                cellNum = row.getPhysicalNumberOfCells();
                System.out.println("cell number is " + cellNum);
                for(int j = 0; j < cellNum; j++){
                    cell=row.getCell(j);

                    System.out.println("row " + i + "cell "+ j + ":" + getCellValue(cell));
                }
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

4.设置单元格格式

//set font style red and bold
HSSFFont font = wb.createFont();
font.setColor(HSSFFont.COLOR_RED);
font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);

//create style
HSSFCellStyle cellStyle1 = wb.createCellStyle();
cellStyle1.setFont(font);

//use this style
HSSFCell cell1 = row.createCell(1);
cell.setCellStyle(cellStyle1);
cell.setCellType(HSSFCell.CELL_TYPE_STRING);
cell.setCellValue("Title");