https://www.cnblogs.com/hhhshct/p/7255915.html

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一、需要匯入的jar

　　1.commons-collections4-4.1.jar

　　2.poi-3.17-beta1.jar

　　3.poi-ooxml-3.17-beta1.jar

　　4.poi-ooxml-schemas-3.17-beta1.jar

　　5.xmlbeans-2.6.0.jar

  <dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.17</version>
</dependency>
 

二、主要API

　　1.import org.apache.poi.ss.usermodel.Workbook,對應Excel文件；

　　2.import org.apache.poi.hssf.usermodel.HSSFWorkbook，對應xls格式的Excel文件；

　　3.import org.apache.poi.xssf.usermodel.XSSFWorkbook，對應xlsx格式的Excel文件；

　　4.import org.apache.poi.ss.usermodel.Sheet，對應Excel文件中的一個sheet；

　　5.import org.apache.poi.ss.usermodel.Row，對應一個sheet中的一行；

　　6.import org.apache.poi.ss.usermodel.Cell，對應一個單元格。

三、程式碼如下

package poi;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.DateUtil;
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;

public class Testpoi {

    public static void main(String[] args) {
        Workbook wb =null;
        Sheet sheet = null;
        Row row = null;
        List<Map<String,String>> list = null;
        String cellData = null;
        String filePath = "D:\\test.xlsx";
        String columns[] = {"name","age","score"};
        wb = readExcel(filePath);
        if(wb != null){
            //用來存放表中資料
            list = new ArrayList<Map<String,String>>();
            //獲取第一個sheet
            sheet = wb.getSheetAt(0);
            //獲取最大行數
            int rownum = sheet.getPhysicalNumberOfRows();
            //獲取第一行
            row = sheet.getRow(0);
            //獲取最大列數
            int colnum = row.getPhysicalNumberOfCells();
            for (int i = 1; i<rownum; i++) {
                Map<String,String> map = new LinkedHashMap<String,String>();
                row = sheet.getRow(i);
                if(row !=null){
                    for (int j=0;j<colnum;j++){
                        cellData = (String) getCellFormatValue(row.getCell(j));
                        map.put(columns[j], cellData);
                    }
                }else{
                    break;
                }
                list.add(map);
            }
        }
        //遍歷解析出來的list
        for (Map<String,String> map : list) {
            for (Entry<String,String> entry : map.entrySet()) {
                System.out.print(entry.getKey()+":"+entry.getValue()+",");
            }
            System.out.println();
        }

    }
    //讀取excel
    public static Workbook readExcel(String filePath){
        Workbook wb = null;
        if(filePath==null){
            return null;
        }
        String extString = filePath.substring(filePath.lastIndexOf("."));
        InputStream is = null;
        try {
            is = new FileInputStream(filePath);
            if(".xls".equals(extString)){
                return wb = new HSSFWorkbook(is);
            }else if(".xlsx".equals(extString)){
                return wb = new XSSFWorkbook(is);
            }else{
                return wb = null;
            }
            
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return wb;
    }
    public static Object getCellFormatValue(Cell cell){
        Object cellValue = null;
        if(cell!=null){
            //判斷cell型別
            switch(cell.getCellType()){
            case Cell.CELL_TYPE_NUMERIC:{
                cellValue = String.valueOf(cell.getNumericCellValue());
                break;
            }
            case Cell.CELL_TYPE_FORMULA:{
                //判斷cell是否為日期格式
                if(DateUtil.isCellDateFormatted(cell)){
                    //轉換為日期格式YYYY-mm-dd
                    cellValue = cell.getDateCellValue();
                }else{
                    //數字
                    cellValue = String.valueOf(cell.getNumericCellValue());
                }
                break;
            }
            case Cell.CELL_TYPE_STRING:{
                cellValue = cell.getRichStringCellValue().getString();
                break;
            }
            default:
                cellValue = "";
            }
        }else{
            cellValue = "";
        }
        return cellValue;
    }

}
 

四、執行結果

　　程式碼執行前保證在D盤下有一個test.xlsx文件，不然報檔案找不到異常；Excel文件中的表頭要和程式碼中的String columns[] = {"name","age","score"}對應起來。

例2

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

import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class TestExcel {

	public static void main(String[] args) throws IOException{
	      // 建立工作薄 xlsx
		XSSFWorkbook  xssWorkbook = new XSSFWorkbook();
	      // 建立工作表
		XSSFSheet  sheet = xssWorkbook.createSheet("sheet1");

	      for (int row = 0; row < 10; row++)
	      {
	    	  XSSFRow  rows = sheet.createRow(row);
	         for (int col = 0; col < 10; col++)
	         {
	            // 向工作表中新增資料
	            rows.createCell(col).setCellValue("data" + row + col);
	         }
	      }
//
	      File xlsFile = new File("poi.xlsx");
	      FileOutputStream xlsStream = new FileOutputStream(xlsFile);
	      xssWorkbook.write(xlsStream);
	}
}