SpringBoot多线程查询实战-查询库中所有数据多线程实现

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.stereotype.Service;
 
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
 
@Service
public class MultiThreadQueryService {
 
    @Autowired
    private YourRepository yourRepository;
 
    public List<YourEntity> queryAllDataMultiThread(int pageSize) {
        ExecutorService executorService = Executors.newFixedThreadPool(10); // 创建线程池
        List<Future<List<YourEntity>>> futures = new ArrayList<>();
        List<YourEntity> allData = new ArrayList<>();
 
        int totalPages = (int) yourRepository.count() / pageSize + 1;
        for (int i = 0; i < totalPages; i++) {
            int page = i;
            Future<List<YourEntity>> future = executorService.submit(new Callable<List<YourEntity>>() {
                @Override
                public List<YourEntity> call() throws Exception {
                    PageRequest pageRequest = PageRequest.of(page, pageSize);
                    Page<YourEntity> pageData = yourRepository.findAll(pageRequest);
                    return pageData.getContent();
                }
            });
            futures.add(future);
        }
 
        // 合并所有线程的结果
        for (Future<List<YourEntity>> future : futures) {
            try {
                allData.addAll(future.get());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
 
        executorService.shutdown(); // 关闭线程池
        return allData;
    }
}

这段代码使用了Spring Data JPA的YourRepository来查询数据，并且使用了Java的ExecutorService来实现多线程查询。通过创建一个固定大小的线程池，并提交多个Callable任务来分页查询数据库中的数据，最后合并所有线程的结果。这种方式可以有效提高数据查询的效率，尤其是在处理大量数据时。