gunshi-project-ss/src/main/java/com/gunshi/project/xyt/util/ExcelUtil.java

package com.gunshi.project.xyt.util;

import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.io.resource.ClassPathResource;
import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.ExcelWriter;
import com.alibaba.excel.support.ExcelTypeEnum;
import com.alibaba.excel.write.builder.ExcelWriterSheetBuilder;
import com.alibaba.excel.write.metadata.WriteSheet;
import com.gunshi.project.xyt.util.excel.ExcelFillCellMergeStrategy;
import com.gunshi.project.xyt.util.excel.ExcelListener;
import com.gunshi.project.xyt.util.excel.ExcelResult;
import com.gunshi.project.xyt.util.excel.VoteTitleHandler;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.Map;

public class ExcelUtil {

    /**
     * 导出excel
     *
     * @param list      导出数据集合,加动态表头
     * @param filename 工作表的名称
     * @param clazz     实体类
     * @param response  响应体
     */
    public static <T> void exportExcel(List<T> list, String filename, Class<T> clazz, HttpServletResponse response,String sheetName) {
        OutputStream out = null;
        try {
            out = getOutputStream(filename,response);
            ExcelWriterSheetBuilder builder = EasyExcel.write(out, clazz)
                    //是否自动关闭流
                    .autoCloseStream(Boolean.FALSE)
                    //自动列宽(不太精确)
                    .registerWriteHandler(new VoteTitleHandler(filename))
                    .sheet(sheetName);
            builder.doWrite(list);
        } finally {
            try {
                if (out != null){
                    out.flush();
                    out.close();
                }
            } catch (IOException e) {
                throw new RuntimeException("导出Excel异常");
            }
        }
    }

    /**
     * 导出动态列
     * @param head 表头
     * @param data 数据
     * @param filename
     * @param response
     * @param sheetName
     * @param <T>
     */
    public static <T> void exportExcel(List<List<String>> head,List<T> data, String filename, HttpServletResponse response,String sheetName) {
        OutputStream out = null;
        try {
            out = getOutputStream(filename,response);
            ExcelWriterSheetBuilder builder = EasyExcel.write(out)
                    //是否自动关闭流
                    .autoCloseStream(Boolean.FALSE)
                    //自动列宽(不太精确)
                    .registerWriteHandler(new VoteTitleHandler(filename))
                    .head(head)
                    .sheet(sheetName);
            builder.doWrite(data);
        } finally {
            try {
                if (out != null){
                    out.flush();
                    out.close();
                }
            } catch (IOException e) {
                throw new RuntimeException("导出Excel异常");
            }
        }
    }

    /**
     *导出动态列，带合并单元格
     * @param head 表头
     * @param data 表格数据
     * @param mergeRowIndex 从第几行开始合并
     * @param mergeColumnIndex 合并字段的下标，如第一到五列new int[]{0,1,2,3,4}
     * @param filename
     * @param response
     * @param sheetName
     * @param <T>
     */
    public static <T> void exportExcel(List<List<String>> head,List<T> data,int mergeRowIndex,int[] mergeColumnIndex, String filename, HttpServletResponse response,String sheetName) {
        OutputStream out = null;
        try {
            out = getOutputStream(filename,response);
            ExcelWriterSheetBuilder builder = EasyExcel.write(out)
                    //是否自动关闭流
                    .autoCloseStream(Boolean.FALSE)
                    .registerWriteHandler(new ExcelFillCellMergeStrategy(mergeRowIndex,mergeColumnIndex))
                    .head(head)
                    .sheet(sheetName);
            builder.doWrite(data);
        } finally {
            try {
                if (out != null){
                    out.flush();
                    out.close();
                }
            } catch (IOException e) {
                throw new RuntimeException("导出Excel异常");
            }
        }
    }

    /**
     * 单表多数据模板导出 模板格式为 {.属性}
     *
     * @param filename     文件名
     * @param templatePath 模板路径 resource 目录下的路径包括模板文件名
     *                     例如: excel/temp.xlsx
     *                     重点: 模板文件必须放置到启动类对应的 resource 目录下
     * @param data         模板需要的数据
     * @param list         模板需要的集合数据
     */
    public static <T> void exportTemplate(Map<String, Object> data, List<T> list, String filename, String templatePath, HttpServletResponse response) {
        OutputStream out = null;
        try {
            out = getOutputStream(filename,response);
            ClassPathResource templateResource = new ClassPathResource(templatePath);
            ExcelWriter excelWriter =  EasyExcel.write(out)
                    .withTemplate(templateResource.getStream())
                    .excelType(ExcelTypeEnum.XLSX)
                    .build();
            WriteSheet writeSheet = EasyExcel.writerSheet().build();
            if (CollUtil.isEmpty(data)) {
                throw new IllegalArgumentException("数据为空");
            }
            excelWriter.fill(list,writeSheet);
            excelWriter.fill(data, writeSheet);
            excelWriter.finish();
        } finally {
            try {
                if (out != null){
                    out.flush();
                    out.close();
                }
            } catch (IOException e) {
                throw new RuntimeException("导出Excel异常");
            }
        }
    }

    private static OutputStream getOutputStream(String fileName, HttpServletResponse response) {
        try {
            fileName = URLEncoder.encode(fileName, StandardCharsets.UTF_8);
            response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=UTF-8");
            response.setCharacterEncoding("utf8");
            response.setHeader("Content-Disposition", "attachment; filename=" + fileName + ".xlsx");
            response.setHeader("Pragma", "public");
            response.setHeader("Cache-Control", "no-store");
            response.addHeader("Cache-Control", "max-age=0");
            return response.getOutputStream();
        } catch (IOException e) {
            System.out.println(e.getMessage());
        }
        return null;
    }

    /**
     * 使用自定义监听器 异步导入 自定义返回
     *
     * @param is       输入流
     * @param clazz    对象类型
     * @param listener 自定义监听器
     * @return 转换后集合
     */
    public static <T> ExcelResult<T> importExcel(InputStream is, Class<T> clazz, ExcelListener<T> listener) {
        EasyExcel.read(is, clazz, listener).sheet().doRead();
        return listener.getExcelResult();
    }

}