多人同时导出Excel干崩服务器？新来的大佬优雅解决

• ExportQueue：维护一条定长队列，可以获取队列里前后排队的用户，提供查询，队列如果已经满了，其余的人需要进行等待

• User信息：排队执行导出方法对应用户；

• Export类：定义导出方法，异步执行，用户可以通过导出页面查看、下载，导出的文件。

具体代码实现

package com.example.system.config;
import com.example.system.api.domain.ExportUser;import lombok.extern.slf4j.Slf4j;import org.springframework.stereotype.Component;
import java.util.LinkedList;
@Slf4j@Componentpublic class ExportQueue {

    private final int MAX_CAPACITY = 10; // 队列最大容量    private LinkedList<ExportUser> queue; // 用户队列
    public ExportQueue(LinkedList<ExportUser> queue) {        this.queue = new LinkedList<>();    }    /**     * 排队队列添加     * @param sysUser     */    public synchronized LinkedList<ExportUser> add(ExportUser sysUser) {        while (queue.size() >= MAX_CAPACITY) {            try {                log.info("当前排队人已满，请等待");                wait();            } catch (InterruptedException e) {                e.getMessage();            }        }        queue.add(sysUser);        log.info("目前导出队列排队人数：" + queue.size());        notifyAll();        return queue;    }
    /**     * 获取排队队列下一个人     * @return     */    public synchronized ExportUser getNextSysUser() {        while (queue.isEmpty()) {            try {                wait();            } catch (InterruptedException e) {                e.printStackTrace();            }        }        ExportUser sysUser = queue.remove();        notifyAll(); //唤醒        return sysUser;    }}

package com.example.system.config;

import cn.hutool.core.bean.BeanUtil;import cn.hutool.core.util.PageUtil;import com.alibaba.excel.EasyExcel;import com.alibaba.excel.ExcelWriter;import com.alibaba.excel.write.metadata.WriteSheet;import com.example.system.api.domain.ExportUser;import lombok.extern.slf4j.Slf4j;
import javax.servlet.http.HttpServletResponse;import java.io.IOException;import java.net.URLEncoder;import java.util.List;
@Slf4jpublic abstract class AbstractExport<T, K> {

    public abstract void export(ExportUser sysUser) throws InterruptedException;    /**     * 导出     *     * @param response 输出流     * @param pageSize 每页大小     * @param t        导出条件     * @param k        Excel内容实体类     * @param fileName 文件名称     */    public void export(HttpServletResponse response, int pageSize, T t, Class<K> k, String fileName) throws Exception {        ExcelWriter writer = null;        try {            writer = getExcelWriter(response, fileName);            //查询导出总条数            int total = this.countExport(t);            //页数            int loopCount = PageUtil.totalPage(total, pageSize);            BeanUtil.setProperty(t, "pageSize", pageSize);            for (int i = 0; i < loopCount; i++) {                //开始页                BeanUtil.setProperty(t, "pageNum", PageUtil.getStart(i + 1, pageSize));                //获取Excel导出信息                List<K> kList = this.getExportDetail(t);                WriteSheet writeSheet = EasyExcel.writerSheet(fileName).head(k).build();                writer.write(kList, writeSheet);            }        } catch (Exception e) {            String msg = "导出" + fileName + "异常";            log.error(msg, e);            throw new Exception(msg + e);        } finally {            if (writer != null) {                writer.finish();            }        }    }

    public com.alibaba.excel.ExcelWriter getExcelWriter(HttpServletResponse response, String fileName) throws IOException {        response.setContentType("application/vnd.ms-excel");        response.setCharacterEncoding("utf-8");        // 这里URLEncoder.encode可以防止中文乱码 当然和easyexcel没有关系        String fileNameUtf = URLEncoder.encode(fileName, "UTF-8").replaceAll("\\+", "%20");        response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileNameUtf + ".xlsx");        return EasyExcel.write(response.getOutputStream()).build();    }
    /**     * （模版导出）     *     * @param t     * @param fileName     * @param response     */    public abstract void complexFillWithTable(T t, String fileName, HttpServletResponse response);    /**     * 查询导出总条数     *     * @param t     * @return     */    public abstract int countExport(T t);    /**     * 查询导出数据     *     * @param t     * @return     */    public abstract List<K> getExportDetail(T t);}

package com.example.system.service.impl;
import com.alibaba.excel.ExcelWriter;import com.example.system.api.domain.ExportUser;import com.example.system.config.AbstractExport;import com.example.system.config.ExportQueue;import lombok.extern.slf4j.Slf4j;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;
import javax.servlet.http.HttpServletResponse;import java.io.IOException;import java.util.LinkedList;import java.util.List;
@Service@Slf4jpublic class ExportImpl extends AbstractExport {
    @Autowired    private ExportQueue exportQueue;

    @Override    public void export(ExportUser sysUser) throws InterruptedException {
        //导出        log.info("导出文件方法执行～～～～～～～～～");//        export(response,pageSize,t,k,fileName);        LinkedList<ExportUser> queue = exportQueue.add(sysUser);        log.info("导出队列：" + queue);        //休眠时间稍微设置大点，模拟导出处理时间        Thread.sleep(20000);        //导出成功后移除当前导出用户        ExportUser nextSysUser = exportQueue.getNextSysUser();        log.info("移除后获取下一个排队的用户: " + nextSysUser.getUserName());
    }

    @Override    public void export(HttpServletResponse response, int pageSize, Object o, Class k, String fileName) throws Exception {        super.export(response, pageSize, o, k, fileName);    }
    @Override    public ExcelWriter getExcelWriter(HttpServletResponse response, String fileName) throws IOException {        return super.getExcelWriter(response, fileName);    }
    @Override    public void complexFillWithTable(Object o, String fileName, HttpServletResponse response) {
    }
    @Override    public int countExport(Object o) {        return 0;    }
    @Override    public List getExportDetail(Object o) {        return null;    }}

package com.example.system.controller;
import com.example.system.api.domain.ExportUser;import com.example.system.api.domain.SysUser;import com.example.system.service.impl.ExportImpl;import lombok.SneakyThrows;import lombok.extern.slf4j.Slf4j;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.PostMapping;import org.springframework.web.bind.annotation.RequestBody;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;
@RestController@RequestMapping("/export")@Slf4jpublic class ExportController {
    @Autowired    private ExportImpl export;

    @PostMapping("/exportFile")    public void exportFile() {            new Thread(new Runnable() {                @SneakyThrows                @Override                public void run() {                    Thread thread1 = Thread.currentThread();                    ExportUser sysUser =new ExportUser();                    sysUser.setUserName(thread1.getName());
                    export.export(sysUser);                }            }).start();        }}

其余的还未实现，导出文件的表的设计、oss文件上传、用户导出文件下载，还有高并发的场景下会不会出现什么问题，这些都还没有太考虑进去；实现的方式应该挺多的，Redis的队列应该也是可以的，这里仅仅提供一个实现思路。