通过poi读取Excel的内容

package com.cp.base.util;

import com.cp.annotation.NameAnnotation;
import org.apache.poi.ss.usermodel.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class ExcelUtil {

    final static Logger logger = LoggerFactory.getLogger(ExcelUtil.class);

        /**
         * 解析excel
         * @param in
         * @return
         * @throws IOException
         */
        public static List<Map<Integer,Object>> parseExcel(InputStream in) throws IOException {
            List<Map<Integer,Object>> list = new ArrayList<>();
            //此种创建方式兼容2003 2007
            Workbook workbook = WorkbookFactory.create(in);
            //获取第一个工作簿 有且只有一个
            Sheet sheet = workbook.getSheetAt(0);
            //获取第一行
            int firstRowNum = sheet.getFirstRowNum();

            Row row = null;

            if (firstRowNum > 0){
                //校验表头信息 是否匹配
                Row firstRow = sheet.getRow(firstRowNum);

                //总列数
                int lastCellNum = firstRow.getLastCellNum();
                //第一列
                //int firstCellNum = firstRow.getFirstCellNum();

                if (lastCellNum > 0){
                    //遍历所有的行
                    for (int i = firstRowNum + 1;i < sheet.getLastRowNum(); i++){
                        //每一行
                        row = sheet.getRow(i);
                        Map<Integer,Object> map = new HashMap<>();
                        //遍历所有的列
                        for (int j = row.getFirstCellNum(); j < row.getLastCellNum(); j++){

                            Cell cell = row.getCell(j);

                            Object value = getValue(cell);

                            map.put(j,value);

                        }
                        list.add(map);

                    }
                }
            }
            return list;
        }

    /**
     * 解析excel
     * @param in
     * @return
     * @throws IOException
     */
    public static <T> List<T> parseExcel(InputStream in,Class<T> clazz) throws IOException, IllegalAccessException, InstantiationException {

        List<T> model = new ArrayList<>();

        //此种创建方式兼容2003 2007
        Workbook workbook = WorkbookFactory.create(in);
        //获取第一个工作簿 有且只有一个
        Sheet sheet = workbook.getSheetAt(0);
        //获取第一行
        int firstRowNum = sheet.getFirstRowNum();

        Row row = null;

        if (firstRowNum > 0){
            //校验表头信息 是否匹配
            Row firstRow = sheet.getRow(firstRowNum);

            //总列数
            int lastCellNum = firstRow.getLastCellNum();
            logger.info("总列数：{}",lastCellNum);
            //第一列
            //int firstCellNum = firstRow.getFirstCellNum();

            if (lastCellNum > 0){
                //遍历所有的行
                for (int i = firstRowNum + 1;i < sheet.getLastRowNum(); i++){
                    //每一行
                    row = sheet.getRow(i);

                    //创建实例
                    T t = clazz.newInstance();

                    //遍历所有的列
                    for (int j = row.getFirstCellNum(); j < row.getLastCellNum(); j++){

                        if (row.getCell(j) != null){
                            //获取所有属性
                            Field[] fields = clazz.getDeclaredFields();

                            for (Field field : fields){
                                //允许访问私有属性值
                                field.setAccessible(true);
                                //表头 与字段对应
                                NameAnnotation annotation = field.getAnnotation(NameAnnotation.class);
                                if(annotation == null){
                                    continue;

                                } else {

                                    //获取表头
                                    String headName = ((String) getValue(firstRow.getCell(j))).trim();

                                    logger.info("表头：{}",headName);
                                    logger.info("注解名称：{}",annotation.name());

                                    if (headName.equals(annotation.name())){
                                        final Class<?> type = field.getType();
                                        logger.info("属性类型：{}",type.toString());

                                        if (type.equals(String.class)){
                                            field.set(t,row.getCell(j).getStringCellValue().trim());
                                        }

                                        if (type.equals(Integer.class)){
                                            field.set(t,new Integer((Integer) getValue(row.getCell(j))));
                                        }

                                        if (type.equals(BigDecimal.class)){
                                            field.set(t,new BigDecimal(getValue(row.getCell(j)).toString()));
                                        }

                                    }


                                }
                            }
                            model.add(t);
                        }

                    }
                }
            }
        }
        logger.info("解析结果：{}",model);
        return model;
    }

        /**
         * 获取不同类型的值
         * @param cell
         * @return
         */
        private static Object getValue(Cell cell){

            Object value = null;

            switch (cell.getCellType()) {
                case STRING:
                    value = cell.getStringCellValue();
                    break;
                case NUMERIC:
                    value = cell.getNumericCellValue();
                    break;
                default:
                    value =  "";
                    break;
            }
            return  value;
        }

}

package com.cp.annotation;

import java.lang.annotation.*;

/**
 * 注解 excel表头与字段对应
 */
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface NameAnnotation {

   String name() default "";

}