JPA实现@Query手写原生sql拼接动态sql并分页的方法

import java.math.BigDecimal;
import java.util.Collections;
import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;

import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageImpl;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Repository;


@Repository("dao")
public class CrawlerHistoryLogDaoImpl implements CrawlerNewHistoryDao {
	
	@PersistenceContext
	private EntityManager entityManager;
	
 
	@Override
    public Page<Object[]> getHistoryInfo(String crawlerId,
                                         String startDate,
                                         String description,
                                         Pageable pageable) {

        StringBuffer dataBuffer = new StringBuffer(
                "select h.title,h.CONTENT_URL,h.HISTORY_ID,h.CHANNEL_URL,h.description,f.FILE_LOCAL,c.CRAWLER_NAME,h.CREATE_TIME from XT_PC_CRAWLER_HISTORY h left join XT_PC_CRAWLER_FILE f on h.HISTORY_ID=f.ITEM_ID left join XT_PC_CRAWLER c on h.CRAWLER_ID=c.CRAWLER_ID WHERE 1 = 1");
        StringBuffer countBuffer = new StringBuffer(
                "select count(h.HISTORY_ID) from XT_PC_CRAWLER_HISTORY h left join XT_PC_CRAWLER_FILE f on h.HISTORY_ID=f.ITEM_ID left join XT_PC_CRAWLER c on h.CRAWLER_ID=c.CRAWLER_ID WHERE 1 = 1");
		
		StringBuffer paramBuffer = new StringBuffer();
		
        if (crawlerId != null) {
            paramBuffer.append(" AND h.CRAWLER_ID = '" + crawlerId + "'");
        }
		if(startDate != null) {
            paramBuffer
                    .append(" AND h.CREATE_TIME like '%" + startDate + "%'");
		}
        if (description != null && description.equals("0")) {
            paramBuffer.append(" AND h.description is not null ");
        }
        if (description != null && description.equals("1")) {
            paramBuffer.append(" AND h.description is  null ");
        }
        StringBuffer orderBuffer = new StringBuffer(
                " order by h.CREATE_TIME desc");

        String dataSql = (dataBuffer.append(paramBuffer).append(orderBuffer))
                .toString();
		String countSql = (countBuffer.append(paramBuffer)).toString();
		
		System.out.println("{} dataSql= " + dataSql);
		System.out.println("{} countSql= " + countSql);
		
        Query dataQuery = entityManager.createNativeQuery(dataSql.toString());
		Query countQuery = entityManager.createNativeQuery(countSql.toString());
		
		dataQuery.setFirstResult(pageable.getOffset());
		dataQuery.setMaxResults(pageable.getPageSize());
		BigDecimal count = (BigDecimal) countQuery.getSingleResult();
		Long total = count.longValue();
        List<Object[]> content = total > pageable.getOffset() ? dataQuery
                .getResultList() : Collections.emptyList();
        return new PageImpl<>(content, pageable, total);
        // return null;
	}

}