1、线程池类

@Configuration
@Getter
public class GisOrderThreadPool {

    @Bean
    public ThreadPoolTaskExecutor taskExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(10);  // 核心线程数
        executor.setMaxPoolSize(20);   // 最大线程数
        executor.setQueueCapacity(500); // 队列容量
        executor.setThreadNamePrefix("GisOrderExecutor-"); // 线程名的前缀
        executor.initialize();
        return executor;
    }
}

2、异步查询函数： 分页查询再汇总

//异步 分页查询再汇总
    public List<GisOrderDto> processGisInstallOrderDtoListAsyn(GisOrderParam gisOrderParam) {
        List<GisOrderDto> list = new ArrayList<>();
        int pageSize = 1500; // 每页查询的数量，根据实际需求调整
        //数据总量
        int totalCount =  gisOrderDAO.selectGisInstallOrderCount(gisOrderParam);
        //分批的总次数
        int totalPage = (int) Math.ceil((double) totalCount / pageSize);

        //用spring托管的线程池，避免经常创建和释放线程池
        Executor executor = threadPool.taskExecutor().getThreadPoolExecutor();
        List<CompletableFuture<List<GisOrderDto>>> futures = new ArrayList<>();

        for (int currentPage = 1; currentPage <= totalPage; currentPage++) {
            //用于lambda 表达式内部必须是final，所以currentPage不能直接用, 为每个线程创建新的finalCurrentPage
            int finalCurrentPage = currentPage;
            //由于gisOrderParam是共享的，set内容 有多线程安全问题，所以为每个线程新new一个 localParam
            GisOrderParam localParam = new GisOrderParam();
            BeanUtils.copyProperties(gisOrderParam, localParam);
            //每个分页查询都会被包装成一个CompletableFuture，并提交给线程池进行异步处理
            CompletableFuture<List<GisOrderDto>> future = CompletableFuture.supplyAsync(() -> {
                localParam.setOffset((finalCurrentPage - 1) * pageSize);
                localParam.setLimit(pageSize);
                return gisOrderDAO.selectGisInstallOrder(localParam);
            }, executor);
            futures.add(future);
        }

        //使用CompletableFuture.allOf()等待所有任务完成，然后将结果合并到最终的list中
        CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]))
                .thenAccept(v -> {
                    for (CompletableFuture<List<GisOrderDto>> future : futures) {
                        try {
                            list.addAll(future.get());
                        }
                        catch (Exception e) {
                            logger.info("分批查询异常");
                        }
                    }
                })
                .join();

        return list;

    }