Hibernate QBC

介绍：

QBC（Query By Criteria）通过 API 来检索对象

主要由 Criteria 接口、Criterion 接口和 Exception 类组成，支持在运行时动态生成查询语句。

声明

事先定义：Department Employee 两个实体类

示例

查询

List
    
      empList = session.createCriteria(Employee.class).list();
    

分页

List
    
      empList = session.createCriteria(Employee.class).setFirestResult(0).setMaxResults(4).list();
    

Like 查询，忽略大小写

List
    
      empList = session.createCriteria(Employee.class).add(Restrictions.like("ename","a",MatchMode.ANYWHERE).ignoreCase()).list();
    

between 查询

list
    
      empList = session.createCriteria(Employee.class).add(Restrictions.between("hiredate",begindate,enddate)).list();
    

in 查询

list
    
      empList = session.createCriteria(Employee.class).add(Restrictions.in("id",new Integer[]{12,123})).list();
    

> 或 >=

list
    
      empList = session.createCriteria(Employee.class).add(Restrictions.ge("id",123)).list();
    

多条件查询

list
    
      empList = session.createCriteria(Employee.class).add(Restrictions.ge("id",123)).add(Restrictions.between("hiredate",begindate,enddate)).add(Restrictions.like("ename","a", MatchMode.ANYWHERE).ignoreCase()).list();
    

排序

list
    
      empList = session.createCriteria(Employee.class).addOrder(Order.desc("salary")).list();
    

统计

list
    
      empList = session.createCriteria(Employee.class).setProjection(Projections.rowCount()).add(Restrictions.eq("dept.id",20)).list();
    

count 统计

list
    
      empList = session.createCriteria(Employee.class).setProjection(Projection.projectionList().add(Projetions.property("dept.id")).add(Projections.rowCount()).add(Projections.avg("salary")).add(Projections.max("salary")).add(Projections.min("salary")).add(Projections.sum("salary")).add(Projections.groupProperty("dept.id"))).list();
    

非空查询

list
    
      empList = session.createCriteria(Employee.class).add(Restrictions.isNotNull("comm")).list();