Java分段查询小算法

水深无声 2022-11-22 00:12 180阅读 0赞

需求，多线程分段查询

public static void main(String[] args) throws InterruptedException { 
            Integer threadNum = 50;
            Integer pdcount = 99149;
            pdcount = pdcount + 100; // 多+100 防止少查数据
            System.out.println("共有"+pdcount+"条数据");
            String qdm = "310115";
            // 分片
            Integer partNum = (pdcount/threadNum);
            ConcurrentLinkedDeque<String> sqlList = new ConcurrentLinkedDeque<>();
    
            System.out.println("每个线程要处理的数量="+(pdcount/threadNum));
            ExecutorService executorService = Executors.newFixedThreadPool(threadNum);
            for (Integer i = 0; i < threadNum; i++) { 
                Integer finalI = i;
                executorService.execute(new Runnable() { 
                    @Override
                    public void run() { 
                        Integer tPreIndex = (finalI * partNum);
                        Integer tNextIndex = (partNum * (finalI + 1));
                        String jbxxSql = "select * from (select * " +
                                " from t_fwjbxx where QDM = '" + qdm + "' ) where num > "+tPreIndex+" and num < "+tNextIndex;
                        sqlList.add(jbxxSql);
                    }
                });
            }
    
            for (String s : sqlList) { 
                System.out.println(s);
                Thread.sleep(700l);
            }
            System.out.println(sqlList);
        }

结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTQxMzE2MTc_size_16_color_FFFFFF_t_70_pic_center]

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