Restrictions用法

Posted 2020-12-28 hahajava

HQL运算符	QBC运算符	含义
=	Restrictions.eq()	等于equal
<>	Restrictions.ne()	不等于not equal
>	Restrictions.gt()	大于greater than
>=	Restrictions.ge()	大于等于greater than or equal
<	Restrictions.lt()	小于less than
<=	Restrictions.le()	小于等于less than or equal
is null	Restrictions.isnull()	等于空值
is not null	Restrictions.isNotNull()	非空值
like	Restrictions.like()	字符串模式匹配
and	Restrictions.and()	逻辑与
and	Restrictions.conjunction()	逻辑与
or	Restrictions.or()	逻辑或
or	Restrictions.disjunction()	逻辑或
not	Restrictions.not()	逻辑非
in(列表)	Restrictions.in()	等于列表中的某一个值
not in(列表)	Restrictions.not(Restrictions.in())	不等于列表中任意一个值
between x and y	Restrictions.between()	闭区间xy中的任意值
not between x and y	Restrictions.not(Restrictions..between())	小于值X或者大于值y

 

 

2，QBC常用限定方法

 

Restrictions.eq --> equal,等于.

Restrictions.allEq --> 参数为Map对象,使用key/value进行多个等于的比对,相当于多个Restrictions.eq的效果

Restrictions.gt --> great-than > 大于

Restrictions.ge --> great-equal >= 大于等于

Restrictions.lt --> less-than, < 小于

Restrictions.le --> less-equal <= 小于等于

Restrictions.between --> 对应SQL的between子句

Restrictions.like --> 对应SQL的LIKE子句

Restrictions.in --> 对应SQL的in子句

Restrictions.and --> and 关系

Restrictions.or --> or 关系

Restrictions.isNull --> 判断属性是否为空,为空则返回true

Restrictions.isNotNull --> 与isNull相反

Restrictions.sqlRestriction --> SQL限定的查询

Order.asc --> 根据传入的字段进行升序排序

Order.desc --> 根据传入的字段进行降序排序

MatchMode.EXACT --> 字符串精确匹配.相当于"like ‘value‘"

MatchMode.ANYWHERE --> 字符串在中间匹配.相当于"like ‘%value%‘"

MatchMode.START --> 字符串在最前面的位置.相当于"like ‘value%‘"

MatchMode.END --> 字符串在最后面的位置.相当于"like ‘%value‘"

例子
查询年龄在20-30岁之间的所有学生对象
List list = session.createCriteria(Student.class)
      .add(Restrictions.between("age",new Integer(20),new Integer(30)).list();
查询学生姓名在AAA,BBB,CCC之间的学生对象
String[] names = {"AAA","BBB","CCC"};
List list = session.createCriteria(Student.class)
      .add(Restrictions.in("name",names)).list();
查询年龄为空的学生对象
List list = session.createCriteria(Student.class)
      .add(Restrictions.isNull("age")).list();
查询年龄等于20或者年龄为空的学生对象
List list = session.createCriteria(Student.class)
      .add(Restrictions.or(Restrictions.eq("age",new Integer(20)),
                 Restrictions.isNull("age")).list();

--------------------------------------------------------------------
使用QBC实现动态查询 
public List findStudents(String name,int age){

 Criteria criteria = session.createCriteria(Student.class);
 if(name != null){
  criteria.add(Restrictions.liek("name",name,MatchMode.ANYWHERE));
 }
 if(age != 0){
  criteria.add(Restrictions.eq("age",new Integer(age)));
 }
 criteria.addOrder(Order.asc("name"));//根据名字升序排列
 return criteria.list();
}

 

 public List findByCriteria(Object[] args) {
        return HibernateSessionFactory
                .getSession()
                .createCriteria(Emp.class)
                // and
                .add(Restrictions.eq("id", 123))
                .add(Restrictions.gt("hriedate", "1985-4-1"))
                .add(Restrictions.ge("hriedate", "1985-4-1"))
                .add(Restrictions.lt("hriedate", "1985-4-1"))
                .add(Restrictions.le("hriedate", "1985-4-1"))
                // or
                .add(Restrictions.or(Restrictions.eq("id", 123),
                        Restrictions.gt("hriedate", "1985-4-1")))
                // 多个or
                .add(Restrictions.disjunction().add(Restrictions.eq("id", 123))
                        .add(Restrictions.gt("hriedate", "1985-4-1"))
                        .add(Restrictions.ge("hriedate", "1985-4-1")))
                // 各种条件
                .add(Restrictions.between("age", "19", "25"))
                // 张(STRAT是张在开头（END是张在后头）（ANYWHERE任何位置）（EXACT严格匹配）)%
                .add(Restrictions.like("name", "zhang", MatchMode.START))
                .add(Restrictions.ilike("name", "zhang"))
                // 忽略大小写
                .add(Restrictions.in("id", args))
                .add(Restrictions.isEmpty("emps"))
                // Dept.emps(针对集合) 没有员工的部门
                .add(Restrictions.isNotEmpty("emps"))
                .add(Restrictions.not(Restrictions.isEmpty("emps")))// 给某些不带一对的条件取反用的
                .add(Restrictions.isNull("sal"))// sal is null
                .add(Restrictions.isNotNull("sal"))// sal is not null
                .add(Restrictions.sizeEq("emps", 5))// 查询部门人数等于 5个的
                .add(Restrictions.eq("id", 5)).add(Restrictions.ne("id", 5))// 不等于5
                .add(Restrictions.eqProperty("birthday", "hiredate"))// 两个属性相等，其他属性也一样F
                .list();

    }

    }