excel导出工具类

package com.jianwu.util.excel;

import com.google.common.collect.Lists;
import com.jianwu.exception.MobileException;
import com.jianwu.util.excel.annotation.ExcelAttribute;
import org.apache.poi.hssf.usermodel.HSSFCell;
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.poifs.filesystem.POIFSFileSystem;
import org.apache.poi.ss.usermodel.Cell;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.*;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;

/**
 * poi工具类
 * Created by tookbra on 2016/3/30.
 */
public class PoiUtil<T> {
    private static final Logger logger = LoggerFactory.getLogger(PoiUtil.class);
//    private static final String templatePath = "excel/template.txt";
    private static String templatePath = "excel/template.txt";

    Class<T> clazz;

    public PoiUtil(Class<T> clazz) {
        this.clazz = clazz;
    }

    public PoiUtil(Class<T> clazz, String templatePath) {
        this.clazz = clazz;
        this.templatePath = templatePath;
    }


    public static List excelList = null;

    static {
        if(excelList == null)
            excelList = read(templatePath);
    }


    /**
     * 配置文件的读取
     *
     * @param fileName
     *            文件名称
     * @return List 文件内容存放code,name格式
     */
    public static List read(String fileName) {
        File file = new File(PoiUtil.class.getClassLoader().getResource(PoiUtil.templatePath).getFile());
        List list = Lists.newArrayList();
        if (file != null) {
            if (file.exists()) {
                try {
                    BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file)));
                    String str = null;
                    while ((str=br.readLine())!=null) {
                        list.add(str);
                    }
                }
                catch (Exception e) {
                    logger.error("读取excel文本错误:{}", e.getMessage());
                }
            }
            else {
                logger.error("读取excel文本错误，文件不存在");
                System.out.println(fileName + "not exits");
            }
        }
        return list;
    }

    public static String subText(String str,String field) {
        try{
            if (str == null || str.length() == 0 || field == null || field.length() == 0)
                return str;
            for(int i = 0;i<str.length();i++){
                if(field.indexOf(str.charAt(i)) != -1){
                    return str.substring(0,i);
                }
            }
        }catch(Exception ex){
            logger.error("分割截取字符串时发生错误:{}", ex.getMessage());
        }
        return str;
    }

    /**
     * 获取单元格内值
     * @param cell 单元格
     * @return
     */
    public static String getCellValue(Cell cell) {
        Object obj = "";
        switch (cell.getCellType()) {
            case Cell.CELL_TYPE_STRING :
                obj = cell.getStringCellValue();
                break;
            case Cell.CELL_TYPE_NUMERIC :
                obj = cell.getNumericCellValue();
                break;
            case Cell.CELL_TYPE_ERROR :
                obj = cell.getErrorCellValue();
                break;
            case Cell.CELL_TYPE_FORMULA :
                obj = cell.getCellFormula();
                break;
            case Cell.CELL_TYPE_BOOLEAN :
                obj = cell.getBooleanCellValue();
                break;
            case Cell.CELL_TYPE_BLANK:
                break;
        }
        return String.valueOf(obj).trim();
    }

    public HSSFWorkbook exportExcel(List<T> list) throws IOException, IllegalAccessException {
        // excel中每个sheet中最多有65536行
        int sheetSize = 65536;

        HSSFWorkbook wb = new HSSFWorkbook();
        HSSFSheet sheet = wb.createSheet();
        int listSize = 0;
        if (list != null && list.size() >= 0) {
            listSize = list.size();
        }
        int endNo = Math.min(1 + sheetSize, listSize);
        HSSFRow row;
        // 得到所有定义字段
        Field[] allFields = clazz.getDeclaredFields();
        List<Field> fields = new ArrayList<Field>();
        // 得到所有field并存放到一个list中
        for (Field field : allFields) {
            if (field.isAnnotationPresent(ExcelAttribute.class)) {
                fields.add(field);
            }
        }
        HSSFCell cell;// 产生单元格
        row = sheet.createRow(0);// 产生一行
        // 写入各个字段的列头名称
        for (int i = 0; i < fields.size(); i++) {
            Field field = fields.get(i);
            ExcelAttribute attr = field
                    .getAnnotation(ExcelAttribute.class);
            int col = getExcelCol(attr.column());// 获得列号
            cell = row.createCell(col);// 创建列
            cell.setCellType(HSSFCell.CELL_TYPE_STRING);// 设置列中写入内容为String类型
            cell.setCellValue(attr.value());// 写入列名
        }

        logger.info("导出{}条数据", endNo);
        for (int i = 0; i < endNo; i++) {
            row = sheet.createRow(i + 1);
            // 得到导出对象.
            T vo = (T) list.get(i);
            for (int j = 0; j < fields.size(); j++) {
                Field field = fields.get(j);// 获得field.
                field.setAccessible(true);// 设置实体类私有属性可访问
                ExcelAttribute attr = field.getAnnotation(ExcelAttribute.class);
                if (attr.isExport()) {
                    cell = row.createCell(getExcelCol(attr.column()));// 创建cell
                    cell.setCellType(HSSFCell.CELL_TYPE_STRING);
                    cell.setCellValue(field.get(vo) == null ? ""
                            : String.valueOf(field.get(vo)));// 如果数据存在就填入,不存在填入空格.
                    //sheet.autoSizeColumn(j);//自动列宽
                }
            }
        }
        return wb;
    }

    /**
     *
     * @param templatePath
     * @param sheetName
     * @param list
     * @throws IOException
     * @throws IllegalAccessException
     */
    public HSSFWorkbook exportExcel(String templatePath, String sheetName, List<T> list)
            throws IOException, IllegalAccessException {
        // excel中每个sheet中最多有65536行
        int sheetSize = 65536;
        File file = new File(this.getClass().getClassLoader().getResource(templatePath).getFile());
        if(!file.exists()){
            System.out.println("模板文件:" + templatePath + "不存在!");
            throw new MobileException("","");
        }
        POIFSFileSystem fs = new POIFSFileSystem(new FileInputStream(file));
        HSSFWorkbook wb = new HSSFWorkbook(fs);
        HSSFSheet sheet = wb.getSheet(sheetName);
        int listSize = 0;
        if (list != null && list.size() >= 0) {
            listSize = list.size();
        }
        int endNo = Math.min(2 + sheetSize, listSize);
        HSSFRow row;
        // 得到所有定义字段
        Field[] allFields = clazz.getDeclaredFields();
        List<Field> fields = new ArrayList<Field>();
        // 得到所有field并存放到一个list中
        for (Field field : allFields) {
            if (field.isAnnotationPresent(ExcelAttribute.class)) {
                fields.add(field);
            }
        }
        HSSFCell cell;// 产生单元格
        logger.info("导出{}条数据", endNo);
        for (int i = 0; i < endNo; i++) {
            row = sheet.createRow(i + 2);
            // 得到导出对象.
            T vo = (T) list.get(i);
            for (int j = 0; j < fields.size(); j++) {
                Field field = fields.get(j);// 获得field.
                field.setAccessible(true);// 设置实体类私有属性可访问
                ExcelAttribute attr = field.getAnnotation(ExcelAttribute.class);
                if (attr.isExport()) {
                    cell = row.createCell(getExcelCol(attr.column()));// 创建cell
                    cell.setCellType(HSSFCell.CELL_TYPE_STRING);
                    cell.setCellValue(field.get(vo) == null ? ""
                            : String.valueOf(field.get(vo)));// 如果数据存在就填入,不存在填入空格.
                }
            }
        }
        return wb;
    }

    /**
     * 将EXCEL中A,B,C,D,E列映射成0,1,2,3
     *
     * @param col
     */
    public static int getExcelCol(String col) {
        col = col.toUpperCase();
        // 从-1开始计算,字母重1开始运算。这种总数下来算数正好相同。
        int count = -1;
        char[] cs = col.toCharArray();
        for (int i = 0; i < cs.length; i++) {
            count += (cs[i] - 64) * Math.pow(26, cs.length - 1 - i);
        }
        return count;
    }

}