Excel自動導出poi

傳入需要導出的數據列表。自動導出Excel。在導出表比較多的情況可以省點代碼。

原理：

    反射和註解

第一步：

    先定義註解。註解的作用的，標註哪些字段需要導出，以及字段的標題。

import java.lang.annotation.*;

/**
 * 少   年   辛   苦   終   身   事
 * 莫   向   光   陰   惰   寸   功
 * Today the best performance  as tomorrow newest starter!
 * Created by IntelliJ IDEA.
 *
 * @author : songsong.wu
 * github: https://github.com/songdesy
 * email: [email protected]
 * <p>
 * Date: 2019/2/18 3:02 PM
 * Description:
 * Copyright(©) 2019/2/18 by songsong.wu.
 **/
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ExcelField {
    String filedName() default "";
}

第二步：

    在需要導出的實體類的字段上加上註解。如：

    注意，使用的lombok。自行修改

import com.fasterxml.jackson.annotation.JsonFormat;
import lombok.*;

import javax.persistence.*;
import java.io.Serializable;
import java.util.Date;

/**
 * @author
 */

@Table(name = "sys_test")
@Entity
@ToString(callSuper = true)
@EqualsAndHashCode(callSuper = false)
@AllArgsConstructor
@NoArgsConstructor
@Data
public class SysTest implements Serializable {
    private static final long serialVersionUID = -27388489913014L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private String id;

   

    @ExcelField(filedName = "測試一")
    @Column(name = "test1")
    private String test1;

    @ExcelField(filedName = "測試一")
    @Column(name = "test2")
    private Float test2;

    @ExcelField(filedName = "備註")
    @Column(name = "remarks")
    private String remarks;

    @Column(name = "history_flag")
    private String historyFlag = "0";


    @Column(name = "create_date")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date createDate;

    @Column(name = "update_date")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date updateDate;

    @Column(name = "del_flag")
    private String delFlag = "0";


}

第三步：

    導出，使用的是poi 4.0.1

import org.apache.commons.collections.CollectionUtils;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.FileOutputStream;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;

/**
 * 少   年   辛   苦   終   身   事
 * 莫   向   光   陰   惰   寸   功
 * Today the best performance  as tomorrow newest starter!
 * Created by IntelliJ IDEA.
 *
 * @author : songsong.wu
 * github: https://github.com/songdesy
 * email: [email protected]
 * <p>
 * Date: 2018/8/2 下午6:44
 * Description:
 * Copyright(©) 2018/8/2 by songsong.wu.
 **/
public class ExcelExportUtil {


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

    public static void exportExcel(List list, String excelName, String sheetName) {

        if (CollectionUtils.isEmpty(list)) {
            return;
        }
        Workbook wb = createWorkbook();
        CellStyle cellStyle = createCellStyle(wb);
        Font font = wb.createFont();
        Sheet sheet = createSheet(wb, sheetName);
        int rowIndex = 1;
        for (Object o : list) {
            Row row = sheet.createRow(rowIndex);
            int cellIndex = 0;
            Class cls = o.getClass();
            Field[] fields = cls.getDeclaredFields();
            for (Field field : fields) {
                field.setAccessible(true);
                Annotation annotation = field.getAnnotation(ExcelField.class);
                if (annotation != null) {
                    Object value = fieldValue(field, o);
                    if (value != null) {
                        createCell(value, cellStyle, row, cellIndex, HorizontalAlignment.CENTER, VerticalAlignment.CENTER, font);
                    }
                    cellIndex++;
                }

            }
            rowIndex++;
        }
        createTitle(list.get(0), wb, sheet);
        saveFile(wb);

    }

    private static void createTitle(Object o, Workbook wb, Sheet sheet) {
        Row row = sheet.createRow(0);
        int cellIndex = 0;
        Class cls = o.getClass();
        Field[] fields = cls.getDeclaredFields();
        Font font = wb.createFont();
        CellStyle cellStyle = createCellStyle(wb);
        font.setFontHeightInPoints((short) 12);
        font.setFontName("楷體");
        font.setBold(true);

        for (Field field : fields) {
            Annotation annotation = field.getAnnotation(ExcelField.class);
            if (annotation != null) {
                createCell(((ExcelField) annotation).filedName(), cellStyle, row, cellIndex, HorizontalAlignment.CENTER, VerticalAlignment.CENTER, font);
                cellIndex++;
            }
        }

    }

    private static Object fieldValue(Field field, Object o) {
        try {
            return field.get(o);
        } catch (IllegalAccessException e) {
            return null;
        }
    }

    private static void saveFile(Workbook wb) {
        try (OutputStream fileOut = new FileOutputStream("/Users/wss/Downloads/excelImport.xls")) {
            wb.write(fileOut);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static void createCell(Object value, CellStyle cellStyle, Row row, int column, HorizontalAlignment halign, VerticalAlignment valign, Font font) {
        Cell cell = row.createCell(column);
        cell.setCellValue(value.toString());
        cellStyle.setAlignment(halign);
        cellStyle.setVerticalAlignment(valign);
        cellStyle.setFont(font);
        cell.setCellStyle(cellStyle);
    }

    private static Workbook createWorkbook() {
        Workbook wb = new HSSFWorkbook();
        return wb;
    }

    private static CellStyle createCellStyle(Workbook wb) {
        return wb.createCellStyle();
    }

    private static Sheet createSheet(Workbook wb, String sheetName) {
        Sheet sheet1 = wb.createSheet(sheetName);
        return sheet1;
    }

    public static void main(String[] args) {
        SysTest sysTest = new SysTest();
        sysTest.setTest1("hello");
        sysTest.setTest2((float) 10);
        sysTest.setRemarks("謝謝");
        List list = new ArrayList();
        list.add(sysTest);
        ExcelExportUtil.exportExcel(list, "第一個測試", "第一個工作");

    }
}

 

可以直接運行main方法測試！