java利用poi生成/读取excel表格

1.引入jar包依赖

　　　

<dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.9</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>3.8</version>
        </dependency>

2.编写代码测试

 package testweb;

 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.LinkedList;
 import java.util.List;

 import org.apache.poi.hssf.usermodel.HSSFCell;
 import org.apache.poi.hssf.usermodel.HSSFCellStyle;
 import org.apache.poi.hssf.usermodel.HSSFFont;
 import org.apache.poi.hssf.usermodel.HSSFRichTextString;
 import org.apache.poi.hssf.usermodel.HSSFRow;
 import org.apache.poi.hssf.usermodel.HSSFSheet;
 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
 import org.apache.poi.hssf.util.HSSFColor;

 public class TestExcel {

     public static void main(String[] args) {
         List<Object> l=new LinkedList<>();
         l.add("zs");
         l.add("ls");
         l.add("we");
         l.add("mz");
         String[] headers=new String[]{"tou1","tou2","tou3","tou4"};
         try {
             OutputStream o= new FileOutputStream(new File("C:/Users/yanan/Desktop/yanantest.xls"));
             exportDataExcel("nihao",headers,l,o);
         } catch (FileNotFoundException e) {
             e.printStackTrace();
         }
     }

     protected static void exportDataExcel(String title,String[] headers,List<Object> mapList,OutputStream out){
         //声明一个工作簿
         HSSFWorkbook workbook = new HSSFWorkbook();
         //生成一个表格
         HSSFSheet sheet = workbook.createSheet(title);
         //设置表格默认列宽度字符
         sheet.setDefaultColumnWidth(20);
         //生成一个样式，用来设置标题样式
         HSSFCellStyle style = workbook.createCellStyle();
         //设置这些样式
         style.setFillForegroundColor(HSSFColor.SKY_BLUE.index);
         style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
         style.setBorderBottom(HSSFCellStyle.BORDER_THIN);
         style.setBorderLeft(HSSFCellStyle.BORDER_THIN);
         style.setBorderRight(HSSFCellStyle.BORDER_THIN);
         style.setBorderTop(HSSFCellStyle.BORDER_THIN);
         style.setAlignment(HSSFCellStyle.ALIGN_CENTER);
         //生成一个字体
         HSSFFont font = workbook.createFont();
         font.setColor(HSSFColor.VIOLET.index);
         font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
         //把字体应用到当前的样式
         style.setFont(font);
         // 生成并设置另一个样式,用于设置内容样式
         HSSFCellStyle style2 = workbook.createCellStyle();
         style2.setFillForegroundColor(HSSFColor.LIGHT_YELLOW.index);
         style2.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
         style2.setBorderBottom(HSSFCellStyle.BORDER_THIN);
         style2.setBorderLeft(HSSFCellStyle.BORDER_THIN);
         style2.setBorderRight(HSSFCellStyle.BORDER_THIN);
         style2.setBorderTop(HSSFCellStyle.BORDER_THIN);
         style2.setAlignment(HSSFCellStyle.ALIGN_CENTER);
         style2.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);
         // 生成另一个字体
         HSSFFont font2 = workbook.createFont();
         font2.setBoldweight(HSSFFont.BOLDWEIGHT_NORMAL);
         // 把字体应用到当前的样式
         style2.setFont(font2);
         //产生表格标题行
         HSSFRow row = sheet.createRow(0);
         for (int i = 0; i < headers.length; i++) {
             HSSFCell cell = row.createCell(i);
             cell.setCellStyle(style);
             HSSFRichTextString text = new HSSFRichTextString(headers[i]);
             cell.setCellValue(text);
         }
         for (int i = 0; i < mapList.size(); i++) {
             row = sheet.createRow(i + 1);
             int j = 0;
             HSSFCell cell = row.createCell(j++);
             cell.setCellValue("循环获得值1");
             cell.setCellStyle(style2);
             row.createCell(j++).setCellValue("循环获得值2");
             row.createCell(j++).setCellValue("循环获得值3");
             row.createCell(j++).setCellValue("循环获得值4");
         }
         try {
             workbook.write(out);
         } catch (IOException e) {
             e.printStackTrace();
         }
     }
 }

package testweb;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.poi.hssf.usermodel.HSSFDateUtil;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;

public class TestExcel {
    public static void main(String[] args) {
        try {
            FileInputStream file = new FileInputStream("C:/Users/yanan/Desktop/yanan.xls");
            List<Map<String, Object>> yanantest = duquexcel(file);
            for (Map<String, Object> item : yanantest) {
                System.out.println(item.get("id") + "," + item.get("name") + "," + item.get("gendar")+","+item.get("time"));
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }

    public static List<Map<String, Object>> duquexcel(InputStream fis) {
        List<Map<String, Object>> resultList = new ArrayList<Map<String, Object>>();
        HSSFWorkbook wb;
        try {
            wb = new HSSFWorkbook(new POIFSFileSystem(fis));
            Sheet sheet = wb.getSheetAt(0);
            // 日期格式化
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy/M/dd");
            // 数字格式化
            DecimalFormat df = new DecimalFormat("##");
            // 循环xls中的每个表格
            Row firstRow = sheet.getRow(0);

            for (int i = sheet.getFirstRowNum() + 1; i <= sheet.getLastRowNum(); i++) {
                Row row = sheet.getRow(i);
                Map<String, Object> rowMap = new HashMap<String, Object>();

                for (int k = 0; k < row.getLastCellNum(); k++) {
                    Cell cell = row.getCell(k);
                    if (null == cell) {
                        continue;
                    }
                    switch (cell.getCellType()) {
                    case Cell.CELL_TYPE_NUMERIC:
                        if(HSSFDateUtil.isCellDateFormatted(cell)){
                            rowMap.put(firstRow.getCell(k).getStringCellValue(),sdf.format(HSSFDateUtil.getJavaDate(cell.getNumericCellValue())) );
                            break;
                        }
                        double value_d = cell.getNumericCellValue();
                        long value_l = (long) cell.getNumericCellValue();// cell.getCellStyle()获取样式
                        if (value_d == value_l)
                            rowMap.put(firstRow.getCell(k).getStringCellValue(), String.valueOf(value_l));
                        else
                            rowMap.put(firstRow.getCell(k).getStringCellValue(), String.valueOf(value_d));
                        break;
                    case Cell.CELL_TYPE_STRING:
                        rowMap.put(firstRow.getCell(k).getStringCellValue(), cell.getStringCellValue());
                        break;
                    case Cell.CELL_TYPE_BLANK:
                        break;
                    default:
                        rowMap.put(firstRow.getCell(k).getStringCellValue(), cell.toString());
                        break;
                    }
                }
                // 是否空行
                if (rowMap.size() > 0) {
                    resultList.add(rowMap);
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return resultList;
    }
}