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从零搭建自己的SpringBoot后台框架(二十)

Hello大家好，本章我们添加导出Excel表格功能。有问题可以联系我mr_beany@163.com。另求各路大神指点，感谢

在实际工作中，有时候会需要将列表数据导出为Excel形式，方便打印，同事间传阅等，所以本章将添加将列表数据导出为Excel形式

一：添加POI依赖

<dependency>
   <groupId>org.apache.poi</groupId>
   <artifactId>poi-ooxml</artifactId>
   <version>3.9</version>
</dependency>

二：创建Excel实体类

package com.example.demo.model;

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

public class ExcelData implements Serializable {

    private static final long serialVersionUID = 6133772627258154184L;
    /**
     * 表头
     */
    private List<String> titles;

    /**
     * 数据
     */
    private List<List<Object>> rows;

    /**
     * 页签名称
     */
    private String name;

    public List<String> getTitles() {
        return titles;
    }

    public void setTitles(List<String> titles) {
        this.titles = titles;
    }

    public List<List<Object>> getRows() {
        return rows;
    }

    public void setRows(List<List<Object>> rows) {
        this.rows = rows;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

三：创建表格工具类

创建core→utils→ExcelUtils

package com.example.demo.core.utils;

import com.example.demo.model.ExcelData;
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 javax.servlet.http.HttpServletResponse;
import java.awt.Color;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.List;

public class ExcelUtils {

    /**
     * 使用浏览器选择路径下载
     * @param response
     * @param fileName
     * @param data
     * @throws Exception
     */
    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 + ".xls", "utf-8"));
        exportExcel(data, response.getOutputStream());
    }

    public static int generateExcel(ExcelData excelData, String path) throws Exception {
        File f = new File(path);
        FileOutputStream out = new FileOutputStream(f);
        return exportExcel(excelData, out);
    }

    private static int exportExcel(ExcelData data, OutputStream out) throws Exception {
        XSSFWorkbook wb = new XSSFWorkbook();
        int rowIndex = 0;
        try {
            String sheetName = data.getName();
            if (null == sheetName) {
                sheetName = "Sheet1";
            }
            XSSFSheet sheet = wb.createSheet(sheetName);
            rowIndex = writeExcel(wb, sheet, data);
            wb.write(out);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            //此处需要关闭 wb 变量
            out.close();
        }
        return rowIndex;
    }

    private static int writeExcel(XSSFWorkbook wb, Sheet sheet, ExcelData data) {
        int rowIndex = 0;
        writeTitlesToExcel(wb, sheet, data.getTitles());
        rowIndex = writeRowsToExcel(wb, sheet, data.getRows(), rowIndex);
        autoSizeColumns(sheet, data.getTitles().size() + 1);
        return rowIndex;
    }

    /**
     * 设置表头
     *
     * @param wb
     * @param sheet
     * @param titles
     * @return
     */
    private static int writeTitlesToExcel(XSSFWorkbook wb, Sheet sheet, List<String> titles) {
        int rowIndex = 0;
        int colIndex = 0;
        Font titleFont = wb.createFont();
        //设置字体
        titleFont.setFontName("simsun");
        //设置粗体
        titleFont.setBoldweight(Short.MAX_VALUE);
        //设置字号
        titleFont.setFontHeightInPoints((short) 14);
        //设置颜色
        titleFont.setColor(IndexedColors.BLACK.index);
        XSSFCellStyle titleStyle = wb.createCellStyle();
        //水平居中
        titleStyle.setAlignment(XSSFCellStyle.ALIGN_CENTER);
        //垂直居中
        titleStyle.setVerticalAlignment(XSSFCellStyle.VERTICAL_CENTER);
        //设置图案颜色
        titleStyle.setFillForegroundColor(new XSSFColor(new Color(182, 184, 192)));
        //设置图案样式
        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;
    }

    /**
     * 设置内容
     *
     * @param wb
     * @param sheet
     * @param rows
     * @param rowIndex
     * @return
     */
    private static int writeRowsToExcel(XSSFWorkbook wb, Sheet sheet, List<List<Object>> rows, int rowIndex) {
        int colIndex;
        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<Object> rowData : rows) {
            Row dataRow = sheet.createRow(rowIndex);
            dataRow.setHeightInPoints(25);
            colIndex = 0;
            for (Object cellData : rowData) {
                Cell cell = dataRow.createCell(colIndex);
                if (cellData != null) {
                    cell.setCellValue(cellData.toString());
                } else {
                    cell.setCellValue("");
                }
                cell.setCellStyle(dataStyle);
                colIndex++;
            }
            rowIndex++;
        }
        return rowIndex;
    }

    /**
     * 自动调整列宽
     *
     * @param sheet
     * @param columnNumber
     */
    private static void autoSizeColumns(Sheet sheet, int columnNumber) {
        for (int i = 0; i < columnNumber; i++) {
            int orgWidth = sheet.getColumnWidth(i);
            sheet.autoSizeColumn(i, true);
            int newWidth = (int) (sheet.getColumnWidth(i) + 100);
            if (newWidth > orgWidth) {
                sheet.setColumnWidth(i, newWidth);
            } else {
                sheet.setColumnWidth(i, orgWidth);
            }
        }
    }

    /**
     * 设置边框
     *
     * @param style
     * @param border
     * @param color
     */
    private static void setBorder(XSSFCellStyle style, BorderStyle border, XSSFColor color) {
        style.setBorderTop(border);
        style.setBorderLeft(border);
        style.setBorderRight(border);
        style.setBorderBottom(border);
        style.setBorderColor(BorderSide.TOP, color);
        style.setBorderColor(BorderSide.LEFT, color);
        style.setBorderColor(BorderSide.RIGHT, color);
        style.setBorderColor(BorderSide.BOTTOM, color);
    }
}

注意，这里封装了常用的属性，具体api大家可以自行百度

四：创建ExcelConstant

创建core→constant→ExcelConstant

package com.example.demo.core.constant;

public class ExcelConstant {

    /**
     * 生成文件存放路径
     */
    public static final String FILE_PATH = "C://Users//Administrator//Desktop//";

    /**
     * 表格默认名称
     */
    public static final String FILE_NAME = "TEST.xls";
}

五：创建ExcelController

package com.example.demo.controller;

import com.example.demo.core.aop.AnnotationLog;
import com.example.demo.core.constant.ExcelConstant;
import com.example.demo.core.ret.RetResponse;
import com.example.demo.core.ret.RetResult;
import com.example.demo.core.ret.ServiceException;
import com.example.demo.core.utils.ExcelUtils;
import com.example.demo.model.ExcelData;
import com.example.demo.model.UserInfo;
import com.example.demo.service.UserInfoService;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiImplicitParam;
import io.swagger.annotations.ApiImplicitParams;
import io.swagger.annotations.ApiOperation;
import org.apache.shiro.SecurityUtils;
import org.apache.shiro.authc.IncorrectCredentialsException;
import org.apache.shiro.authc.UsernamePasswordToken;
import org.apache.shiro.subject.Subject;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletResponse;
import java.util.ArrayList;
import java.util.List;

@RestController
@RequestMapping("excel")
public class ExcelController {

    @Resource
    private UserInfoService userInfoService;

    @PostMapping("/test")
    public  RetResult<Integer> test(){
        int rowIndex = 0;
        List<UserInfo> list = userInfoService.selectAlla(0, 0);
        ExcelData data = new ExcelData();
        data.setName("hello");
        List<String> titles = new ArrayList();
        titles.add("ID");
        titles.add("userName");
        titles.add("password");
        data.setTitles(titles);

        List<List<Object>> rows = new ArrayList();
        for(int i = 0, length = list.size();i<length;i++){
            UserInfo userInfo = list.get(i);
            List<Object> row = new ArrayList();
            row.add(userInfo.getId());
            row.add(userInfo.getUserName());
            row.add(userInfo.getPassword());
            rows.add(row);
        }
        data.setRows(rows);
        try{
            rowIndex = ExcelUtils.generateExcel(data, ExcelConstant.FILE_PATH + ExcelConstant.FILE_NAME);
        }catch (Exception e){
            e.printStackTrace();
        }
        return RetResponse.makeOKRsp(Integer.valueOf(rowIndex));
    }

    @GetMapping("/test2")
    public void test2(HttpServletResponse response){
        int rowIndex = 0;
        List<UserInfo> list = userInfoService.selectAlla(0, 0);
        ExcelData data = new ExcelData();
        data.setName("hello");
        List<String> titles = new ArrayList();
        titles.add("ID");
        titles.add("userName");
        titles.add("password");
        data.setTitles(titles);

        List<List<Object>> rows = new ArrayList();
        for(int i = 0, length = list.size();i<length;i++){
            UserInfo userInfo = list.get(i);
            List<Object> row = new ArrayList();
            row.add(userInfo.getId());
            row.add(userInfo.getUserName());
            row.add(userInfo.getPassword());
            rows.add(row);
        }
        data.setRows(rows);
        try{
            ExcelUtils.exportExcel(response,"test2",data);
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

六：添加接口权限

INSERT INTO `sys_permission_init` VALUES ('7', '/excel/test', 'anon', '7');
INSERT INTO `sys_permission_init` VALUES ('8', '/excel/test2', 'anon', '8');

这里我们需要测试在浏览器中下载，所以我们先把接口设置为不登录也可以访问