Spring JPA 实现动态SQL查询及分页

1.在持久层Service中创建EntityManager对象；

@PersistenceContext
private EntityManager entityManager;

2.根据动态sql查询条目数

/**
 * get total.
 */
public Object getResultTotalBySql(String sql) {
    Query query = entityManager.createNativeQuery(sql);
    return query.getSingleResult();
}

3.根据动态sql查询数据，T po代表映射的实体类对象

/**
 * get list.
 */
public List getResultListBySql(String sql, T po) {
    Query query = entityManager.createNativeQuery(sql, po.getClass());
    return query.getResultList();
}

//4.根据条目数，每页大小进行总页数

public Long getTotalPage(Long total, int pageSize) {
    return (total + pageSize - 1) / pageSize;
}

完整代码：

/**
     * -----------------
     * Custom sql queries
     * -----------------
     */
    @PersistenceContext
    private EntityManager entityManager;

    /**
     * get total.
     */
    public Object getResultTotalBySql(String sql) {
        Query query = entityManager.createNativeQuery(sql);
        return query.getSingleResult();
    }

    /**
     * get list.
     */
    public List getResultListBySql(String sql, T po) {
        Query query = entityManager.createNativeQuery(sql, po.getClass());
        return query.getResultList();
    }

    public Long getTotalPage(Long total, int pageSize) {
        return (total + pageSize - 1) / pageSize;
    }