poi、Excel工具包，支持map转excel，bean转excel

参数有表头：linkedHashMap的key要与内容的key一致

表内容：map的key或者bean的属性名要与表头的数据保持一致，不要求顺序。

默认保存到系统的临时文件。

下面是代码

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 java.io.BufferedOutputStream;import java.io.FileOutputStream;import java.io.IOException;import java.lang.reflect.Field;import java.util.*;/** * @author niexiang * @Description * @create 2017-12-13 16:18 **/public class PoiUtil {    /**     * Map生成excel表     * @param head (头部的key必须对应map的key)     * @param contents     * @return 返回保存的地址     */    public static String mapToExcel(LinkedHashMap<String,String> head, List<Map> contents,String sheetName,String fileName) {        HSSFWorkbook workbook = new HSSFWorkbook();        HSSFSheet sheet = workbook.createSheet(sheetName);        //生成内容        for (int i = 0;i< contents.size()+1;i++){//excel的行数            HSSFRow row = sheet.createRow(i);            int j = 0;//列            for (Map.Entry<String,String> property : head.entrySet()) {                HSSFCell cell = row.createCell(j++);                if (i == 0) {//表头信息                    cell.setCellValue(property.getValue());                }else{                    cell.setCellValue(contents.get(i - 1).get(property.getKey()) == null ? null :contents.get(i - 1).get(property.getKey()).toString());                }            }        }        String folder=System.getProperty("java.io.tmpdir");        String filePath = folder + "/" + fileName;        return writeFile(workbook,filePath);    }    /**     * bean生成excel表     * @param head (头部的key必须对应bean的属性名)     * @param contents     * @return 返回保存的地址     */    public static <T> String beanToExcel(LinkedHashMap<String,String> head, List<T> contents,String sheetName,String fileName) throws Exception {        HSSFWorkbook workbook = new HSSFWorkbook();        HSSFSheet sheet = workbook.createSheet(sheetName);        Class clazz = contents.get(0).getClass();        //生成内容        for (int i = 0;i< contents.size()+1;i++){//excel的行数            HSSFRow row = sheet.createRow(i);            int j = 0;//列            for (Map.Entry<String,String> property : head.entrySet()) {                HSSFCell cell = row.createCell(j++);                if (i == 0) {//表头信息                    cell.setCellValue(property.getValue());                }else{                    Field field = clazz.getDeclaredField(property.getKey());                    field.setAccessible(true);                    Object result = field.get(contents.get(i - 1));                    cell.setCellValue(result == null ? null :result.toString());                }            }        }        String folder=System.getProperty("java.io.tmpdir");        String filePath = folder + fileName;        return writeFile(workbook,filePath);    }    private static String writeFile(HSSFWorkbook workbook, String filePath) {        FileOutputStream stream = null;        BufferedOutputStream outputStream = null;        try {            stream = new FileOutputStream(filePath);            outputStream = new BufferedOutputStream(stream);            workbook.write(outputStream);            return filePath;        } catch (IOException e) {            e.printStackTrace();        }finally {            if (outputStream != null){                try {                    outputStream.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            if (stream != null){                try {                    stream.close();                } catch (IOException e) {                    e.printStackTrace();                }            }        }        return null;    }    public static void main(String[] args) {        LinkedHashMap<String,String> map = new LinkedHashMap<>();        map.put("name","姓名");        map.put("age","年龄");        map.put("gender","性别");        List<Person> list = new ArrayList<>();        for (int i = 0; i < 10 ; i++) {            list.add(new Person("123",i,"男"));        }        try {            beanToExcel(map,list,"ceshi123","ceshi123.xls");        } catch (Exception e) {            e.printStackTrace();        }    }}