通用Excel文件导出工具类

1：Excel格式

2：ExcelUtil.java

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.lang.reflect.Field;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
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.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.VerticalAlignment;
import org.apache.poi.ss.util.CellRangeAddress;

/**
 * @作者 yan
 * @创建日期
 * @版本 V1.0
 * @描述 Excel 导出通用工具类
 */
public class ExcelUtil {

    public static byte[] export(String sheetTitle, String[] title, List<Object> list) {

        HSSFWorkbook wb = new HSSFWorkbook();//创建excel表
        HSSFSheet sheet = wb.createSheet(sheetTitle);
        sheet.setDefaultColumnWidth(20);//设置默认行宽

        //表头样式（加粗，水平居中，垂直居中）
        HSSFCellStyle cellStyle = wb.createCellStyle();
        cellStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);//水平居中
        cellStyle.setVerticalAlignment(VerticalAlignment.CENTER);//垂直居中
        //设置边框样式
        cellStyle.setBorderBottom(HSSFCellStyle.BORDER_THIN); //下边框
        cellStyle.setBorderLeft(HSSFCellStyle.BORDER_THIN);//左边框
        cellStyle.setBorderTop(HSSFCellStyle.BORDER_THIN);//上边框
        cellStyle.setBorderRight(HSSFCellStyle.BORDER_THIN);//右边框

        HSSFFont fontStyle = wb.createFont();
        fontStyle.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);

        cellStyle.setFont(fontStyle);

        //标题样式（加粗，垂直居中）
        HSSFCellStyle cellStyle2 = wb.createCellStyle();
        cellStyle2.setVerticalAlignment(VerticalAlignment.CENTER);//垂直居中
        cellStyle2.setFont(fontStyle);

        //设置边框样式
        cellStyle2.setBorderBottom(HSSFCellStyle.BORDER_THIN); //下边框
        cellStyle2.setBorderLeft(HSSFCellStyle.BORDER_THIN);//左边框
        cellStyle2.setBorderTop(HSSFCellStyle.BORDER_THIN);//上边框
        cellStyle2.setBorderRight(HSSFCellStyle.BORDER_THIN);//右边框

        //字段样式（垂直居中）
        HSSFCellStyle cellStyle3 = wb.createCellStyle();
        cellStyle3.setVerticalAlignment(VerticalAlignment.CENTER);//垂直居中

        //设置边框样式
        cellStyle3.setBorderBottom(HSSFCellStyle.BORDER_THIN); //下边框
        cellStyle3.setBorderLeft(HSSFCellStyle.BORDER_THIN);//左边框
        cellStyle3.setBorderTop(HSSFCellStyle.BORDER_THIN);//上边框
        cellStyle3.setBorderRight(HSSFCellStyle.BORDER_THIN);//右边框

        //创建表头
        HSSFRow row = sheet.createRow(0);
        row.setHeightInPoints(20);//行高
        
        HSSFCell cell = row.createCell(0);
        cell.setCellValue(sheetTitle);
        cell.setCellStyle(cellStyle);

        sheet.addMergedRegion(new CellRangeAddress(0,0,0,(title.length-1)));
        
        //创建标题
        HSSFRow rowTitle = sheet.createRow(1);
        rowTitle.setHeightInPoints(20);

        HSSFCell hc;
        for (int i = 0; i < title.length; i++) {
            hc = rowTitle.createCell(i);
            hc.setCellValue(title[i]);
            hc.setCellStyle(cellStyle2);
        }

        byte result[] = null;

        ByteArrayOutputStream out = null;
        
        try {
            //创建表格数据
            Field[] fields;
            int i = 2;

            for (Object obj : list) {
                fields = obj.getClass().getDeclaredFields();

                HSSFRow rowBody = sheet.createRow(i);
                rowBody.setHeightInPoints(20);

                int j = 0;
                for (Field f : fields) {

                    f.setAccessible(true);

                    Object va = f.get(obj);
                    if (null == va) {
                        va = "";
                    }

                    hc = rowBody.createCell(j);
                    hc.setCellValue(va.toString());
                    hc.setCellStyle(cellStyle3);
                    
                    j++;
                }

                i++;
            }

            out = new ByteArrayOutputStream();
            wb.write(out);
            result =  out.toByteArray();
        } catch (Exception ex) {
            Logger.getLogger(ExcelUtil.class.getName()).log(Level.SEVERE, null, ex);
        } finally{
            try {
                if(null != out){
                    out.close();
                }
            } catch (IOException ex) {
                Logger.getLogger(ExcelUtil.class.getName()).log(Level.SEVERE, null, ex);
            } finally{
                try {
                    wb.close();
                } catch (IOException ex) {
                    Logger.getLogger(ExcelUtil.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        }

        return result;
    }
}

3：测试

 public static void main(String[] args) {
        String sheetTitle = "用户信息";
        String[] title = {"姓名", "年龄"};
        
        List<Object> list = new ArrayList<Object>();
        
        for(int i=0;i<10;i++){
            User u = new User();
            u.setUname("张三"+i);
            u.setAge(10+i);
            list.add(u);
        }
        
        byte b[] = ExcelUtil.export(sheetTitle, title, list);
        
        File f = new File("G:\tmp\"+sheetTitle+".xls");
        try {
            FileUtils.writeByteArrayToFile(f, b, true);
        } catch (IOException ex) {
            Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

4：依赖包

commons-io-2.4.jar

poi-3.15.jar