记一次用Executors和Callable多线程查询

男娘i 2021-12-16 23:53 110阅读 0赞

# 线程类 #

public class ThredQuery implements Callable<List<StoreCompDetailEntity>> {
    
        private StoreBrokenCompMapper storeBrokenCompMapper;
    
        // 查询条件
        private String dateStr;
    
        // 分页
        private int pageNum;
    
        private Integer pageSize;
    
        public ThredQuery(String dateStr, Integer pageNum, Integer pageSize, StoreBrokenCompMapper storeBrokenCompMapper){
            this.dateStr = dateStr;
            this.pageNum = pageNum + 1;
            this.pageSize = pageSize;
            this.storeBrokenCompMapper = storeBrokenCompMapper;
        }
    
        @Override
        public List<StoreCompDetailEntity> call() throws Exception {
            Map<String, Object> map = new HashMap<String, Object>(3);
            map.put("dateStr", dateStr);
            map.put("pageNum", pageNum);
            map.put("pageSize", pageSize);
            List<StoreCompDetailEntity> result = storeBrokenCompMapper.getStoreCompDetails(map);
            return result;
        }
    }

# 业务类代码 #

Map<String, Object> map = new HashMap<String, Object>();
            map.put("dateStr", dateStr);
            ArrayList<StoreCompDetailEntity> entities = new ArrayList<StoreCompDetailEntity>();
            int nums = 50; //每次查询的条数
            int count = storeBrokenCompMapper.selectStoreCompDetailsCount(map); // 总行数
            int pageCount = (count % nums == 0) ? (count / nums) : (count / nums + 1);// 多少页
            List<Callable<List<StoreCompDetailEntity>>> tasks = new ArrayList<Callable<List<StoreCompDetailEntity>>>();
            for (int i = 0; i < pageCount; i++) {
                Callable<List<StoreCompDetailEntity>> qfe = new ThredQuery(dateStr,i,nums,storeBrokenCompMapper);
                tasks.add(qfe);
            }
            //定义固定长度的线程池  防止线程过多
            ExecutorService executorService = Executors.newFixedThreadPool(15);
            //Future用于获取结果
            List<Future<List<StoreCompDetailEntity>>> futures=executorService.invokeAll(tasks);
            //处理线程返回结果
            if(futures!=null&&futures.size()>0){
                for (Future<List<StoreCompDetailEntity>> future:futures){
                    entities.addAll(future.get());
                }
            }
            for(StoreCompDetailEntity entity : entities){
                if(StringUtil.isNotEmpty(entity.getCreateTime()) && entity.getCreateTime().length() > 19){
                    entity.setCreateTime(entity.getCreateTime().substring(0,19));
                }
            }
            // 关闭线程池
            executorService.shutdown();