使用多线程Callable查询oracle数据库

使用单线程查询10万条数据太慢了，采用多线程进行查询，提高效率。

ThredQuery查询数据的方法

public class ThredQuery implements Callable<List<HashVO>> {
    


    private MyUtil util = new MyUtil();

    private int bindex;//当前页数

    private int num;//每页查询多少条


    private List page;//每次分页查出来的数据
    private String customerName;
    private String customerType;
    private String idType;
    private String idNumb;
    private String updateTime;

    public  ThredQuery(int bindex,int num,String customerName, String customerType, String idType, String idNumb, String updateTime) {
    
        this.bindex=bindex;
        this.num=num;
        this.customerName=customerName;
        this.customerType=customerType;
        this.idType=idType;
        this.idNumb=idNumb;
        this.updateTime=updateTime;
    }


    @Override
    public List<HashVO> call() throws Exception {
    
        String sql = "";

        if (StringUtils.isNotBlank(customerName)) {
    
            sql += " and customer_name like '%" + customerName + "%' ";
        }
        if (StringUtils.isNotBlank(customerType)) {
    
            sql += " and customer_type = '" + customerType + "' ";
        }
        if (StringUtils.isNotBlank(idType)) {
    
            sql += " and id_type = '" + idType + "' ";
        }
        if (StringUtils.isNotBlank(idNumb)) {
    
            sql += " and id_numb like '%" + idNumb + "%' ";
        }
        if (StringUtils.isNotBlank(updateTime)) {
    
            sql += " and (" + updateTime + ")";
        }
        sql += " order by id";
        String finalSql = "SELECT * FROM " +
                "(" +
                "SELECT A.*, ROWNUM RN " +
                "FROM ("
                + sql +
                " ) A " +
                " WHERE ROWNUM <= "+ (bindex*num)+
                " ) " +
                "WHERE RN >= "+(((bindex-1)*num)+1);

        return Arrays.asList(util.getHashVOs(finalSql));
    }

}

注意：call里面就是查询方法。util就是查询数据的，执行sql

oracle分页方法，以pageIndex和pageSize为例

 String sql= "SELECT * FROM " +
                "(" +
                "SELECT A.*, ROWNUM RN " +
                "FROM ("
                + sql +
                " ) A " +
                " WHERE ROWNUM <= "+ (pageIndex*pageSize)+
                " ) " +
                "WHERE RN >= "+(((pageIndex-1)*pageSize)+1);

调用方法:

     private void  getVoListMultiThreading(String customerName, String customerType, String idType, String idNumb, String updateTime)  {
    
        long start = System.currentTimeMillis();//开始时间
        List<HashVO> result = new ArrayList<>();//返回结果
        //查询数据库总数量
        int count = queryCount();
        int num = 8000;//一次查询多少条
        //需要查询的次数
        int times = count / num;
        if (count % num != 0) {
    
            times = times + 1;
        }
        //开始页数 连接的是orcle的数据库 封装的分页方式 我的是从1开始
        //Callable用于产生结果
        List<Callable<List<HashVO>>> tasks = new ArrayList<>();
        for (int i = 1; i <= times; i++) {
    
            //多线程查询
            Callable<List<HashVO>> qfe = new ThredQuery(i, num, customerName, customerType, idType, idNumb, updateTime);
            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
        try {
    
            List<Future<List<HashVO>>> futures=executorService.invokeAll(tasks);
            //处理线程返回结果
            if(futures!=null&&futures.size()>0){
    
                for (Future<List<HashVO>> future:futures){
    
                    result.addAll(future.get());
                }
            }
        } catch (InterruptedException e) {
    
            throw new RuntimeException(e);
        } catch (ExecutionException e) {
    
            throw new RuntimeException(e);
        }
        executorService.shutdown();//关闭线程池
        long end = System.currentTimeMillis();//结束时间
        log.info("查询耗时：" + (end - start) / 1000 + "秒 ","结果: "+result);
    }

查询时间仅用了30s