SpringBoot导出Excel表格

0、先在pom.xml里面添加POI依赖，Java轻熟鸟从第六步看

        <dependency>
            <groupId>org.apache.poigroupId>
            <artifactId>poi-ooxmlartifactId>
            <version>3.8version>
        dependency>

1、编写mapper.xml文件

"1.0" encoding="UTF-8"?>
"-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
"com.hotcomm.prevention.db.mysql.datashow.dc.DcMapper">

    "selectDeviceList" resultType="import你的查询结果的实体类路径">
        SELECT
        dc.*
        FROM
        t_device_all dc
        INNER JOIN
        t_device_group_relation t1
        ON t1.`deviceid` = dc.`id`
        AND t1.`isdelete`
        = 0
        INNER JOIN t_device_group t2
        ON t1.`groupid` = t2.`id`
        AND
        t2.`isdelete` = 0
        INNER JOIN t_user_dgroup_relation t3
        ON
        t3.`devicegroupid` = t2.`id`
        AND t3.`isdelete` = 0
        INNER JOIN t_user t4
        ON t4.`id` = t3.`userid`
        AND t4.`isdelete` = 0
        AND t4.`id` =#{userid}
    

2、写一个存放单表查询结果的实体类（lombok可以自动编译getter和setter,此处省略lombok的配置安装，如需使用请百度）

import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.NoArgsConstructor;

@Table(name = "t_device_all ")
@Data
@EqualsAndHashCode(callSuper = false)
@NoArgsConstructor
public class T_device_all implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    @Column(name = "devnum")
    private String devnum;

    @Column(name = "mac")
    private String mac;

}

3、编辑你的毛片儿（mapper.java）

import java.util.List;
import org.apache.ibatis.annotations.Param;

public interface DcMapper{

    List selectDeviceList(@Param("userid") Integer userid);

}

4、编辑service

import java.text.ParseException;
import java.util.List;

public interface DcService {

    List selectDevice(Integer userid);

}

5、接着是serviceImpl（SpringBoot、SSM是真的优雅）

import java.util.ArrayList;
import org.springframework.beans.factory.annotation.Autowired;

@Service
public class DcServiceImpl implements DcService {

    @Autowired
    private DcMapper dcMapper;

    @Override
    public List selectDevice(Integer userid) {
        return dcMapper.selectDeviceList(userid);
    }

}

6、编写Excel模板实体类

import java.io.Serializable;
import java.util.List;

import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.NoArgsConstructor;

@Data
@EqualsAndHashCode(callSuper = false)
@NoArgsConstructor
public class ExcelData implements Serializable {

    private static final long serialVersionUID = 1L;

    // 表头
    private List titles;

    // 数据
    private List> rows;

    // 页签名称
    private String name;

}

7、编写Excel工具类（设置你要导出的Excel表格样式，基本不需要修改）

import javax.servlet.http.HttpServletResponse;
import java.io.OutputStream;
import java.util.List;

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.usermodel.Font;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFColor;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.apache.poi.xssf.usermodel.extensions.XSSFCellBorder.BorderSide;

import java.awt.Color;
import java.net.URLEncoder;

public class ExcelOutPutUtils {
    public static void exportExcel(HttpServletResponse response, String fileName, ExcelData data) throws Exception {
        // 告诉浏览器用什么软件可以打开此文件
        response.setHeader("content-Type", "application/vnd.ms-excel");
        // 下载文件的默认名称
        response.setHeader("Content-Disposition", "attachment;filename="+URLEncoder.encode(fileName, "utf-8"));
        exportExcel(data, response.getOutputStream());
    }

    public static void exportExcel(ExcelData data, OutputStream out) throws Exception {

        XSSFWorkbook wb = new XSSFWorkbook();
        try {
            String sheetName = data.getName();
            if (null == sheetName) {
                sheetName = "Sheet1";
            }
            XSSFSheet sheet = wb.createSheet(sheetName);
            writeExcel(wb, sheet, data);

            wb.write(out);
        } catch(Exception e){
            e.printStackTrace();
        }finally{
            //此处需要关闭 wb 变量
            out.close();
        }
    }

    private static void writeExcel(XSSFWorkbook wb, Sheet sheet, ExcelData data) {

        int rowIndex = 0;

        rowIndex = writeTitlesToExcel(wb, sheet, data.getTitles());
        writeRowsToExcel(wb, sheet, data.getRows(), rowIndex);
        autoSizeColumns(sheet, data.getTitles().size() + 1);

    }

    private static int writeTitlesToExcel(XSSFWorkbook wb, Sheet sheet, List titles) {
        int rowIndex = 0;
        int colIndex = 0;

        Font titleFont = wb.createFont();
        titleFont.setFontName("simsun");
        //titleFont.setBoldweight(Short.MAX_VALUE);
        // titleFont.setFontHeightInPoints((short) 14);
        titleFont.setColor(IndexedColors.BLACK.index);

        XSSFCellStyle titleStyle = wb.createCellStyle();
        titleStyle.setAlignment(XSSFCellStyle.ALIGN_CENTER);
        titleStyle.setVerticalAlignment(XSSFCellStyle.VERTICAL_CENTER);
        titleStyle.setFillForegroundColor(new XSSFColor(new Color(182, 184, 192)));
        titleStyle.setFillPattern(XSSFCellStyle.SOLID_FOREGROUND);
        titleStyle.setFont(titleFont);
        setBorder(titleStyle, BorderStyle.THIN, new XSSFColor(new Color(0, 0, 0)));

        Row titleRow = sheet.createRow(rowIndex);
        // titleRow.setHeightInPoints(25);
        colIndex = 0;

        for (String field : titles) {
            Cell cell = titleRow.createCell(colIndex);
            cell.setCellValue(field);
            cell.setCellStyle(titleStyle);
            colIndex++;
        }

        rowIndex++;
        return rowIndex;
    }

    private static int writeRowsToExcel(XSSFWorkbook wb, Sheet sheet, List> rows, int rowIndex) {
        int colIndex = 0;

        Font dataFont = wb.createFont();
        dataFont.setFontName("simsun");
        // dataFont.setFontHeightInPoints((short) 14);
        dataFont.setColor(IndexedColors.BLACK.index);

        XSSFCellStyle dataStyle = wb.createCellStyle();
        dataStyle.setAlignment(XSSFCellStyle.ALIGN_CENTER);
        dataStyle.setVerticalAlignment(XSSFCellStyle.VERTICAL_CENTER);
        dataStyle.setFont(dataFont);
        setBorder(dataStyle, BorderStyle.THIN, new XSSFColor(new Color(0, 0, 0)));

        for (List