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java实现excel下载和上传的工具类

java实现excel下载和上传的工具类

网上搜索了很多工具类的写法,大多都是poi的应用,

需要用到的poi的maven包

<!-- 上传excel -->
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.16</version>
        </dependency>
        <!-- 上传excel -->
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>3.16</version>
        </dependency>

其中有一篇写的比较精炼和容易理解,但是却又几处错误无法直接使用,现将修改后的代码粘贴如下:

package com.estun.util;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.apache.log4j.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.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;
import org.apache.poi.ss.usermodel.Cell;
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;

/**
 * excel的上传与下载的工具类
 * @author gaozhen
 * @time 2017年10月30日下午3:02:58
 */
public class ExcelUtil {
    private static final Logger logger = Logger.getLogger(ExcelUtil.class);
    
    /** 
    * @Title: createWorkbook 
    * @Description: 判断excel文件后缀名,生成不同的workbook 
    * @param @param is
    * @param @param excelFileName
    * @param @return
    * @param @throws IOException
    * @return Workbook
    * @throws 
    */
    public Workbook createWorkbook(InputStream is,String excelFileName) throws IOException{
        if (excelFileName.endsWith(".xls")) {
            return new HSSFWorkbook(is);
        }else if (excelFileName.endsWith(".xlsx")) {
            return new XSSFWorkbook(is);
        }
        return null;
    }

    /** 
    * @Title: getSheet 
    * @Description: 根据sheet索引号获取对应的sheet
    * @param @param workbook
    * @param @param sheetIndex
    * @param @return
    * @return Sheet
    * @throws 
    */
    public Sheet getSheet(Workbook workbook,int sheetIndex){
        return workbook.getSheetAt(0);        
    }
    
    /** 
    * @Title: importDataFromExcel 
    * @Description: 将sheet中的数据保存到list中,
    * 1、调用此方法时,vo的属性个数必须和excel文件每行数据的列数相同且一一对应,vo的所有属性都为String
    * 2、在action调用此方法时,需声明 
    *     private File excelFile;上传的文件
    *     private String excelFileName;原始文件的文件名
    * 3、页面的file控件name需对应File的文件名
    * @param @param vo javaBean
    * @param @param is 输入流
    * @param @param excelFileName
    * @param @return
    * @return List<Object>
    * @throws 
    */
    public List<Object> importDataFromExcel(Object vo,InputStream is,String excelFileName){
        List<Object> list = new ArrayList<Object>();
        try {
            //创建工作簿
            Workbook workbook = this.createWorkbook(is, excelFileName);
            //创建工作表sheet
            Sheet sheet = this.getSheet(workbook, 0);
            //获取sheet中数据的行数
            int rows = sheet.getPhysicalNumberOfRows();
            //获取表头单元格个数
            int cells = sheet.getRow(0).getPhysicalNumberOfCells();
            //利用反射,给JavaBean的属性进行赋值
            Field[] fields = vo.getClass().getDeclaredFields();
            for (int i = 1; i < rows; i++) {//第一行为标题栏,从第二行开始取数据
                Row row = sheet.getRow(i);
                int index = 0;
                while (index < cells) {
                    Cell cell = row.getCell(index);
                    if (null == cell) {
                        cell = row.createCell(index);
                    }
                    cell.setCellType(Cell.CELL_TYPE_STRING);
                    String value = null == cell.getStringCellValue()?"":cell.getStringCellValue();
                    
                    Field field = fields[index];
                    String fieldName = field.getName();
                    String methodName = "set"+fieldName.substring(0,1).toUpperCase()+fieldName.substring(1);
                    Method setMethod = vo.getClass().getMethod(methodName, new Class[]{String.class});
                    setMethod.invoke(vo, new Object[]{value});
                    index++;
                }
                if (isHasValues(vo)) {//判断对象属性是否有值
                    list.add(vo);
                    //vo=new Student();
                    //vo.getClass().newInstance();
                    vo=vo.getClass().getConstructor(new Class[]{}).newInstance(new Object[]{});//重新创建一个vo对象
                }
                
            }
        } catch (Exception e) {
        	e.printStackTrace();
            logger.error(e);
        }finally{
            try {
                is.close();//关闭流
            } catch (Exception e2) {
                logger.error(e2);
            }
        }
        return list;
        
    }
    
    /** 
    * @Title: isHasValues 
    * @Description: 判断一个对象所有属性是否有值,如果一个属性有值(分空),则返回true
    * @param @param object
    * @param @return
    * @return boolean
    * @throws 
    */
    public boolean isHasValues(Object object){
        Field[] fields = object.getClass().getDeclaredFields();
        boolean flag = false;
        for (int i = 0; i < fields.length; i++) {
            String fieldName = fields[i].getName();
            String methodName = "get"+fieldName.substring(0, 1).toUpperCase()+fieldName.substring(1);
            Method getMethod;
            try {
                getMethod = object.getClass().getMethod(methodName);
                Object obj = getMethod.invoke(object);
                if (null != obj && !"".equals(obj)) {
                    flag = true;
                    break;
                }
            } catch (Exception e) {
                logger.error(e);
            }
            
        }
        return flag;
        
    }
    
    public <T> void exportDataToExcel(List<T> list,String[] headers,String title,OutputStream os){
        HSSFWorkbook workbook = new HSSFWorkbook();
        //生成一个表格
        HSSFSheet sheet = workbook.createSheet(title);
        //设置表格默认列宽15个字节
        sheet.setDefaultColumnWidth(15);
        //生成一个样式
        HSSFCellStyle style = this.getCellStyle(workbook);
        //生成一个字体
        HSSFFont font = this.getFont(workbook);
        //把字体应用到当前样式
        style.setFont(font);
        
        //生成表格标题
        HSSFRow row = sheet.createRow(0);
        row.setHeight((short)300);
        HSSFCell cell = null;
        
        for (int i = 0; i < headers.length; i++) {        
            cell = row.createCell(i);
            cell.setCellStyle(style);
            HSSFRichTextString text = new HSSFRichTextString(headers[i]);
            cell.setCellValue(text);
        }
        
        //将数据放入sheet中
        for (int i = 0; i < list.size(); i++) {
            row = sheet.createRow(i+1);
            T t = list.get(i);
            //利用反射,根据JavaBean属性的先后顺序,动态调用get方法得到属性的值
            Field[] fields = t.getClass().getFields();
            try {
                for (int j = 0; j < fields.length; j++) {
                    cell = row.createCell(j);
                    Field field = fields[j];
                    String fieldName = field.getName();
                    String methodName = "get"+fieldName.substring(0, 1).toUpperCase()+fieldName.substring(1);
                    Method getMethod = t.getClass().getMethod(methodName,new Class[]{});
                    Object value = getMethod.invoke(t, new Object[]{});
                    
                    if(null == value)
                        value ="";
                    cell.setCellValue(value.toString());
                    
                }
            } catch (Exception e) {
                logger.error(e);
            }
        }
        
        try {
            workbook.write(os);
        } catch (Exception e) {
            logger.error(e);
        }finally{
            try {
                os.flush();
                os.close();
            } catch (IOException e) {
                logger.error(e);
            }
        }
        
    }
    
    /** 
    * @Title: getCellStyle 
    * @Description: 获取单元格格式
    * @param @param workbook
    * @param @return
    * @return HSSFCellStyle
    * @throws 
    */
    public HSSFCellStyle getCellStyle(HSSFWorkbook workbook){
        HSSFCellStyle style = workbook.createCellStyle();
        style.setFillForegroundColor(HSSFColor.GREY_25_PERCENT.index);
        style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
        style.setBorderBottom(HSSFCellStyle.BORDER_THIN);
        style.setBorderTop(HSSFCellStyle.BORDER_THIN);
        style.setLeftBorderColor(HSSFCellStyle.BORDER_THIN);
        style.setRightBorderColor(HSSFCellStyle.BORDER_THIN);
        style.setAlignment(HSSFCellStyle.ALIGN_CENTER);
        
        return style;
    }

    /** 
    * @Title: getFont 
    * @Description: 生成字体样式
    * @param @param workbook
    * @param @return
    * @return HSSFFont
    * @throws 
    */
    public HSSFFont getFont(HSSFWorkbook workbook){
        HSSFFont font = workbook.createFont();
        font.setColor(HSSFColor.WHITE.index);
        font.setFontHeightInPoints((short)12);
        font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
        return font;
    }
    
    public boolean isIE(HttpServletRequest request){
        return request.getHeader("USER-AGENT").toLowerCase().indexOf("msie")>0?true:false;    
    }
}






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