java使用多线程及分页查询数据量很大的数据

调用方法：

import org.springframework.beans.factory.annotation.Autowired;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

public class QueryTest {
    @Autowired
    Object myService;

    public  List<Map<String, Object>> getMaxResult(String sex) throws Exception{
        long start = System.currentTimeMillis();
        List<Map<String, Object>> result=new ArrayList<>();//返回结果
        
        int count = 20000005;//mydao.getCount(); 通过count查到数据总量

        int num = 10000;//每次查询的条数
        //需要查询的次数
        int times=count / num;
        if(count!=0) {
            times=times+1;
        }
        //开始查询的行数
        int bindex = 0;

        List<Callable<List<Map<String, Object>>>> tasks = new ArrayList<Callable<List<Map<String, Object>>>>();//添加任务
        for(int i = 0; i <times ; i++){
            Callable<List<Map<String, Object>>> qfe = new ThredQuery(myService,sex,bindex, num);
            tasks.add(qfe);
            bindex=bindex+num;
        }
        //定义固定长度的线程池  防止线程过多
        ExecutorService execservice = Executors.newFixedThreadPool(15);

        List<Future<List<Map<String, Object>>>> futures = execservice.invokeAll(tasks);
            // 处理线程返回结果
        if (futures != null && futures.size() > 0) {
            for(Future<List<Map<String, Object>>> future : futures) {
                result.addAll(future.get());
            }
        }
        execservice.shutdown();  // 关闭线程池

        long end = System.currentTimeMillis();
        System.out.println("用时"+(start-end));
        
        return result;
    }
}

线程类:

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Callable;

public class ThredQuery  implements Callable<List<Map<String, Object>>> {
    private Object myService;//需要通过够早方法把对应的业务service传进来 实际用的时候把类型变为对应的类型
    private String sex;//查询条件 根据条件来定义该类的属性

    private int bindex;//分页index
    private int num;//数量

    /**
     * 重新构造方法
     * @param myService
     * @param sex
     * @param bindex
     * @param num
     */
    public ThredQuery(Object myService,String sex,int bindex,int num){
        this.myService=myService;
        this.sex=sex;
        this.bindex=bindex;
        this.num=num;
    }

    @Override
    public List<Map<String, Object>> call() throws Exception {
        //通过service查询得到对应结果
        List<Map<String, Object>>  list  =new ArrayList<>(); //myService.queryBySex(sex,bindex,num);

        return list;
    }
}