Hibernate查询—利用Criteria完成表的查询操作

忘是亡心i 2022-06-16 08:53 226阅读 0赞

# **Hibernate 利用Criteria完成表的查询操作** #

1. 在Navicat中创建hibdb数据库并设计department表和user表

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1）department表

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2）users表

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外键

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2. 在myeclipse的DB Browser窗格中创建与数据库hibdb的连接；

3. 为创建的Java工程添加hibernate的支持；

4. 在MyEclipse的DB Browser窗格中利用Hivernate反向工程（Hibernate Reverse Engineering）生成class表和student表的映射文件及POJO类。

（注第2、3、4步骤可以参考我的其它几篇文章）

5. 创建测试类

1）CritiriaDao.java

import java.util.Iterator;
    import java.util.List;
    import java.util.Set;
    
    import org.hibernate.Criteria;
    import org.hibernate.Query;
    import org.hibernate.Session;
    import org.hibernate.criterion.MatchMode;
    import org.hibernate.criterion.Restrictions;
    
    import com.HibernateSessionFactory;
    import com.entity.Department;
    import com.entity.Users;
    
    public class CriteriaDao {
    	public void seDname(String dname){
    		Session session = HibernateSessionFactory.getSession();
    		//根据班级名称查询department表
    		Criteria criteria = session.createCriteria(Department.class);
    		criteria.add(Restrictions.eq("depName", dname));
    		criteria.setMaxResults(20);
    		List result = criteria.list();
    		Iterator it = result.iterator();
    			while(it.hasNext()){
    				Department dep = (Department)it.next();
    				System.out.println("班级id："+dep.getDepId()+"    "+"班级名称:"+dep.getDepName());
    			}
    			session.close();
    	}
    	
    	public void seSname(String sname){
    		//根据学生姓名模糊查询user表
    		Session session = HibernateSessionFactory.getSession();
    		Criteria criteria = session.createCriteria(Users.class);
    		criteria.add(Restrictions.like("usrDesc", sname,MatchMode.ANYWHERE));
    		criteria.setMaxResults(20);
    		List result2 = criteria.list();
    		Iterator it2 = result2.iterator();
    			while(it2.hasNext()){
    				Users user = (Users)it2.next();
    				System.out.println("姓名："+user.getUsrDesc()+"  年龄："+user.getAge()+"  班级："+user.getDepartment().getDepName());
    			}
    			session.close();
    	}
    	
    	public void seExact(String sname){
    		//根据学生姓名精确查询user表
    		Session session = HibernateSessionFactory.getSession();
    		Criteria criteria = session.createCriteria(Users.class);
    		criteria.add(Restrictions.eq("usrDesc", sname));
    		criteria.setMaxResults(20);
    		List result3 = criteria.list();
    		Iterator it3 = result3.iterator();
    			while(it3.hasNext()){
    				Users user = (Users)it3.next();
    				System.out.println("姓名："+user.getUsrDesc()+"  年龄："+user.getAge()+"  班级："+user.getDepartment().getDepName());
    			}
    			session.close();
    	}
    	
    	public void seCombine(String usrDesc,int age){
    		//组合查询
    		Session session = HibernateSessionFactory.getSession();
    		Criteria criteria = session.createCriteria(Users.class);
    		criteria.add(Restrictions.eq("usrDesc", usrDesc)).add(Restrictions.eq("age", age));
    		List result4 = criteria.list();
    		Iterator it4 = result4.iterator();
    			while(it4.hasNext()){
    				Users user = (Users)it4.next();
    				System.out.println("姓名："+user.getUsrDesc()+"  年龄："+user.getAge()+"  班级："+user.getDepartment().getDepName());
    			}
    			session.close();
    	}
    	
    	public void seDep(String depName){
    		//查询某个班级的学生
    		Session session = HibernateSessionFactory.getSession();
    		Criteria criteria = session.createCriteria(Department.class);
    		criteria.add(Restrictions.eq("depName", depName));
    		List result5 = criteria.list();
    		Iterator it5 = result5.iterator();
    
    		while(it5.hasNext()){
    			Department d = (Department)it5.next();
    			Set set = d.getUserses();
    			Iterator its = set.iterator();
    			while(its.hasNext()){
    				System.out.println(
    						"学生姓名："+((Users) its.next()).getUsrDesc());
    			}
    		}
    			session.close();
    	}
    	
    	public void seUsr(String usrDesc){
    		//查询一个学生所在的班级
    		Session session = HibernateSessionFactory.getSession();
    		Criteria criteria = session.createCriteria(Users.class);
    		criteria.add(Restrictions.eq("usrDesc", usrDesc));
    		List result6 = criteria.list();
    		Iterator it6 = result6.iterator();
    			while(it6.hasNext()){			
    				System.out.println(((Users) it6.next()).getDepartment().getDepName());
    			}
    			session.close();
    	}
    
    
    }

2）Test1.java

public class Test1 {
    	public static void main(String[] args) {
    		// TODO Auto-generated method stub
    
    		CriteriaDao hq = new CriteriaDao();
    		//根据班级名称查询department表
    		hq.seDname("101");
    		
    		//根据学生姓名模糊查询user表
    		hq.seSname("li%");
    		
    		//根据学生姓名精确查询user表
    		hq.seExact("lili");
    		
    		//组合查询
    		hq.seCombine("lili", 21);
    		
    		//查询某个班级的学生
    		hq.seDep("101");
    		
    		//查询一个学生所在的班级
    		hq.seUsr("lili");
    
    	}
    
    }

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