Excel import and export use poi custom annotations

Excel import and export use poi custom annotations

Recently, I am doing a data import and export module. I found some examples on the Internet and I will organize it here. I will not post the original author's address here 
(the following code is from the Internet and is not original and slightly modified). 
First, introduce the pom.xml dependency

        <!-- excel工具 -->
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.9</version>
        </dependency>

Use custom annotations

import java.lang.annotation.Retention;  
import java.lang.annotation.RetentionPolicy;  
import java.lang.annotation.Target;  

@Retention(RetentionPolicy.RUNTIME)  
@Target( { java.lang.annotation.ElementType.FIELD })  
public @interface ExcelVOAttribute {  

    /** 
     * 导出到Excel中的名字. 
     */  
    public abstract String name();  

    /** 
     * 配置列的名称,对应A,B,C,D.... 
     */  
    public abstract String column();  

    /** 
     * 提示信息 
     */  
    public abstract String prompt() default "";  

    /** 
     * 设置只能选择不能输入的列内容. 
     */  
    public abstract String[] combo() default {};  

    /** 
     * 是否导出数据,应对需求:有时我们需要导出一份模板,这是标题需要但内容需要用户手工填写. 
     */  
    public abstract boolean isExport() default true;  

} 

Excel tool class

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

import org.apache.poi.hssf.usermodel.DVConstraint;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFDataValidation;
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.util.CellRangeAddressList;

import com.sj.stages.common.excel.annotation.ExcelVOAttribute;  

/* 
 * ExcelUtil工具类实现功能: 
 * 导出时传入list<T>,即可实现导出为一个excel,其中每个对象T为Excel中的一条记录. 
 * 导入时读取excel,得到的结果是一个list<T>.T是自己定义的对象. 
 * 需要导出的实体对象只需简单配置注解就能实现灵活导出,通过注解您可以方便实现下面功能: 
 * 1.实体属性配置了注解就能导出到excel中,每个属性都对应一列. 
 * 2.列名称可以通过注解配置. 
 * 3.导出到哪一列可以通过注解配置. 
 * 4.鼠标移动到该列时提示信息可以通过注解配置. 
 * 5.用注解设置只能下拉选择不能随意填写功能. 
 * 6.用注解设置是否只导出标题而不导出内容,这在导出内容作为模板以供用户填写时比较实用. 
 * 本工具类以后可能还会加功能,请关注我的博客: http://blog.csdn.net/lk_blog 
 */  
public class ExcelUtil<T> {  
    Class<T> clazz;  

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

    public List<T> importExcel(String sheetName, InputStream input) {  
        int maxCol = 0;  
        List<T> list = new ArrayList<T>();  
        try {  
            HSSFWorkbook workbook = new HSSFWorkbook(input);  
            HSSFSheet sheet = workbook.getSheet(sheetName);  
            if (!sheetName.trim().equals("")) {  
                sheet = workbook.getSheet(sheetName);// 如果指定sheet名,则取指定sheet中的内容.  
            }  
            if (sheet == null) {  
                sheet = workbook.getSheetAt(0); // 如果传入的sheet名不存在则默认指向第1个sheet.  
            }  
            int rows = sheet.getPhysicalNumberOfRows();  

            if (rows > 0) {// 有数据时才处理  
                // Field[] allFields = clazz.getDeclaredFields();// 得到类的所有field.  
                List<Field> allFields = getMappedFiled(clazz, null);  

                Map<Integer, Field> fieldsMap = new HashMap<Integer, Field>();// 定义一个map用于存放列的序号和field.  
                for (Field field : allFields) {  
                    // 将有注解的field存放到map中.  
                    if (field.isAnnotationPresent(ExcelVOAttribute.class)) {  
                        ExcelVOAttribute attr = field  
                                .getAnnotation(ExcelVOAttribute.class);  
                        int col = getExcelCol(attr.column());// 获得列号  
                        maxCol = Math.max(col, maxCol);  
                        // System.out.println(col + "====" + field.getName());  
                        field.setAccessible(true);// 设置类的私有字段属性可访问.  
                        fieldsMap.put(col, field);  
                    }  
                }  
                for (int i = 1; i < rows; i++) {// 从第2行开始取数据,默认第一行是表头.  
                    HSSFRow row = sheet.getRow(i);  
                    // int cellNum = row.getPhysicalNumberOfCells();  
                    // int cellNum = row.getLastCellNum();  
                    int cellNum = maxCol;  
                    T entity = null;  
                    for (int j = 0; j < cellNum; j++) {  
                        HSSFCell cell = row.getCell(j);  
                        if (cell == null) {  
                            continue;  
                        }  
                        int cellType = cell.getCellType();  
                        String c = "";  
                        if (cellType == HSSFCell.CELL_TYPE_NUMERIC) {  
                            c = String.valueOf(cell.getNumericCellValue());  
                        } else if (cellType == HSSFCell.CELL_TYPE_BOOLEAN) {  
                            c = String.valueOf(cell.getBooleanCellValue());  
                        } else {  
                            c = cell.getStringCellValue();  
                        }  
                        if (c == null || c.equals("")) {  
                            continue;  
                        }  
                        entity = (entity == null ? clazz.newInstance() : entity);// 如果不存在实例则新建.  
                        // System.out.println(cells[j].getContents());  
                        Field field = fieldsMap.get(j);// 从map中得到对应列的field.  
                        if (field==null) {  
                            continue;  
                        }  
                        // 取得类型,并根据对象类型设置值.  
                        Class<?> fieldType = field.getType();  
                        if (String.class == fieldType) {  
                            field.set(entity, String.valueOf(c));  
                        } else if ((Integer.TYPE == fieldType)  
                                || (Integer.class == fieldType)) {  
                            field.set(entity, Integer.parseInt(c));  
                        } else if ((Long.TYPE == fieldType)  
                                || (Long.class == fieldType)) {  
                            field.set(entity, Long.valueOf(c));  
                        } else if ((Float.TYPE == fieldType)  
                                || (Float.class == fieldType)) {  
                            field.set(entity, Float.valueOf(c));  
                        } else if ((Short.TYPE == fieldType)  
                                || (Short.class == fieldType)) {  
                            field.set(entity, Short.valueOf(c));  
                        } else if ((Double.TYPE == fieldType)  
                                || (Double.class == fieldType)) {  
                            field.set(entity, Double.valueOf(c));  
                        } else if (Character.TYPE == fieldType) {  
                            if ((c != null) && (c.length() > 0)) {  
                                field.set(entity, Character  
                                        .valueOf(c.charAt(0)));  
                            }  
                        }  

                    }  
                    if (entity != null) {  
                        list.add(entity);  
                    }  
                }  
            }  

        } catch (IOException e) {  
            e.printStackTrace();  
        } catch (InstantiationException e) {  
            e.printStackTrace();  
        } catch (IllegalAccessException e) {  
            e.printStackTrace();  
        } catch (IllegalArgumentException e) {  
            e.printStackTrace();  
        }  
        return list;  
    }  

    /** 
     * 对list数据源将其里面的数据导入到excel表单 
     *  
     * @param sheetName 
     *            工作表的名称 
     * @param output 
     *            java输出流 
     */  
    public boolean exportExcel(List<T> lists[], String sheetNames[],  
            OutputStream output) {  
        if (lists.length != sheetNames.length) {  
            System.out.println("数组长度不一致");  
            return false;  
        }  

        HSSFWorkbook workbook = new HSSFWorkbook();// 产生工作薄对象  

        for (int ii = 0; ii < lists.length; ii++) {  
            List<T> list = lists[ii];  
            String sheetName = sheetNames[ii];  

            List<Field> fields = getMappedFiled(clazz, null);  

            HSSFSheet sheet = workbook.createSheet();// 产生工作表对象  

            workbook.setSheetName(ii, sheetName);  

            HSSFRow row;  
            HSSFCell cell;// 产生单元格  
            HSSFCellStyle style = workbook.createCellStyle();  
            style.setFillForegroundColor(HSSFColor.SKY_BLUE.index);  
            style.setFillBackgroundColor(HSSFColor.GREY_40_PERCENT.index);  
            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);  
                ExcelVOAttribute attr = field  
                        .getAnnotation(ExcelVOAttribute.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.name());// 写入列名  

                // 如果设置了提示信息则鼠标放上去提示.  
                if (!attr.prompt().trim().equals("")) {  
                    setHSSFPrompt(sheet, "", attr.prompt(), 1, 100, col, col);// 这里默认设了2-101列提示.  
                }  
                // 如果设置了combo属性则本列只能选择不能输入  
                if (attr.combo().length > 0) {  
                    setHSSFValidation(sheet, attr.combo(), 1, 100, col, col);// 这里默认设了2-101列只能选择不能输入.  
                }  
                cell.setCellStyle(style);  
            }  

            int startNo = 0;  
            int endNo = list.size();  
            // 写入各条记录,每条记录对应excel表中的一行  
            for (int i = startNo; i < endNo; i++) {  
                row = sheet.createRow(i + 1 - startNo);  
                T vo = (T) list.get(i); // 得到导出对象.  
                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  
                    ExcelVOAttribute attr = field  
                            .getAnnotation(ExcelVOAttribute.class);  
                    try {  
                        // 根据ExcelVOAttribute中设置情况决定是否导出,有些情况需要保持为空,希望用户填写这一列.  
                        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.  
                        }  
                    } catch (IllegalArgumentException e) {  
                        e.printStackTrace();  
                    } catch (IllegalAccessException e) {  
                        e.printStackTrace();  
                    }  
                }  
            }  
        }  

        try {  
            output.flush();  
            workbook.write(output);  
            output.close();  
            return true;  
        } catch (IOException e) {  
            e.printStackTrace();  
            System.out.println("Output is closed ");  
            return false;  
        }  

    }  

    /** 
     * 对list数据源将其里面的数据导入到excel表单 
     *  
     * @param sheetName 
     *            工作表的名称 
     * @param sheetSize 
     *            每个sheet中数据的行数,此数值必须小于65536 
     * @param output 
     *            java输出流 
     */  
    @SuppressWarnings("unchecked")
    public boolean exportExcel(List<T> list, String sheetName,  
            OutputStream output) {
        //此处 对类型进行转换
        List<T> ilist = new ArrayList<>();
        for (T t : list) {
            ilist.add(t);
        }
        List<T>[] lists = new ArrayList[1];  
        lists[0] = ilist;  

        String[] sheetNames = new String[1];  
        sheetNames[0] = sheetName;  

        return exportExcel(lists, sheetNames, output);  
    }  

    /** 
     * 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;  
    }  

    /** 
     * 设置单元格上提示 
     *  
     * @param sheet 
     *            要设置的sheet. 
     * @param promptTitle 
     *            标题 
     * @param promptContent 
     *            内容 
     * @param firstRow 
     *            开始行 
     * @param endRow 
     *            结束行 
     * @param firstCol 
     *            开始列 
     * @param endCol 
     *            结束列 
     * @return 设置好的sheet. 
     */  
    public static HSSFSheet setHSSFPrompt(HSSFSheet sheet, String promptTitle,  
            String promptContent, int firstRow, int endRow, int firstCol,  
            int endCol) {  
        // 构造constraint对象  
        DVConstraint constraint = DVConstraint  
                .createCustomFormulaConstraint("DD1");  
        // 四个参数分别是:起始行、终止行、起始列、终止列  
        CellRangeAddressList regions = new CellRangeAddressList(firstRow,  
                endRow, firstCol, endCol);  
        // 数据有效性对象  
        HSSFDataValidation data_validation_view = new HSSFDataValidation(  
                regions, constraint);  
        data_validation_view.createPromptBox(promptTitle, promptContent);  
        sheet.addValidationData(data_validation_view);  
        return sheet;  
    }  

    /** 
     * 设置某些列的值只能输入预制的数据,显示下拉框. 
     *  
     * @param sheet 
     *            要设置的sheet. 
     * @param textlist 
     *            下拉框显示的内容 
     * @param firstRow 
     *            开始行 
     * @param endRow 
     *            结束行 
     * @param firstCol 
     *            开始列 
     * @param endCol 
     *            结束列 
     * @return 设置好的sheet. 
     */  
    public static HSSFSheet setHSSFValidation(HSSFSheet sheet,  
            String[] textlist, int firstRow, int endRow, int firstCol,  
            int endCol) {  
        // 加载下拉列表内容  
        DVConstraint constraint = DVConstraint  
                .createExplicitListConstraint(textlist);  
        // 设置数据有效性加载在哪个单元格上,四个参数分别是:起始行、终止行、起始列、终止列  
        CellRangeAddressList regions = new CellRangeAddressList(firstRow,  
                endRow, firstCol, endCol);  
        // 数据有效性对象  
        HSSFDataValidation data_validation_list = new HSSFDataValidation(  
                regions, constraint);  
        sheet.addValidationData(data_validation_list);  
        return sheet;  
    }  

    /** 
     * 得到实体类所有通过注解映射了数据表的字段 
     *  
     * @param map 
     * @return 
     */  
    @SuppressWarnings("rawtypes")
    private List<Field> getMappedFiled(Class clazz, List<Field> fields) {  
        if (fields == null) {  
            fields = new ArrayList<Field>();  
        }  

        Field[] allFields = clazz.getDeclaredFields();// 得到所有定义字段  
        // 得到所有field并存放到一个list中.  
        for (Field field : allFields) {  
            if (field.isAnnotationPresent(ExcelVOAttribute.class)) {  
                fields.add(field);  
            }  
        }  
        if (clazz.getSuperclass() != null  
                && !clazz.getSuperclass().equals(Object.class)) {  
            getMappedFiled(clazz.getSuperclass(), fields);  
        }  

        return fields;  
    }  
} 

After completing the above steps, a simple excel import and export tool can be used out of the box

Here we take a student as an example

import com.sj.stages.common.excel.annotation.ExcelVOAttribute;

public class StudentVO {  
    @ExcelVOAttribute(name = "序号", column = "A")  
    private int id;  

    @ExcelVOAttribute(name = "姓名", column = "B", isExport = true)  
    private String name;  

    @ExcelVOAttribute(name = "年龄", column = "C", prompt = "年龄保密哦!", isExport = false)  
    private int age;  

    @ExcelVOAttribute(name = "班级", column = "D", combo = { "五期提高班", "六期提高班",  
            "七期提高班" })  
    private String clazz;  

    @ExcelVOAttribute(name = "公司", column = "F")  
    private String company;  

    //省略get/set


}

A simple test  to end

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.List;

import org.apache.log4j.Logger;
import org.junit.Test;

public class ExcelUtilTest {

    private Logger logger = Logger.getLogger(ExcelUtilTest.class);

    @Test
    public void exportExcel(){
        // 初始化数据  
        List<StudentVO> list = new ArrayList<StudentVO>();  

        StudentVO vo = new StudentVO();  
        vo.setId(1);  
        vo.setName("李坤");  
        vo.setAge(26);  
        vo.setClazz("五期提高班");  
        vo.setCompany("天融信");  
        list.add(vo);  

        StudentVO vo2 = new StudentVO();  
        vo2.setId(2);  
        vo2.setName("曹贵生");  
        vo2.setClazz("五期提高班");  
        vo2.setCompany("中银");  
        list.add(vo2);  

        StudentVO vo3 = new StudentVO();  
        vo3.setId(3);  
        vo3.setName("柳波");  
        vo3.setClazz("五期提高班");  
        list.add(vo3);  

        FileOutputStream out = null;  
        try {  
            out = new FileOutputStream("d:\\success3.xls");  
        } catch (FileNotFoundException e) {  
            e.printStackTrace();  
        }  
        ExcelUtil<StudentVO> util = new ExcelUtil<StudentVO>(StudentVO.class);// 创建工具类.  
        util.exportExcel(list, "学生信息", out);// 导出  
        logger.info("----执行完毕----------");  
    }

    @Test
    public void importExcel(){
        FileInputStream fis = null;  
        try {  
            fis = new FileInputStream("d:\\success3.xls");  
            ExcelUtil<StudentVO> util = new ExcelUtil<StudentVO>(  
                    StudentVO.class);// 创建excel工具类  
            List<StudentVO> list = util.importExcel("学生信息0", fis);// 导入  
            logger.info(list);  
        } catch (FileNotFoundException e) {  
            e.printStackTrace();  
        }
    }

}

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