hibernate createsqlquery delete多个表_Java的学习（27）hibernate基础使用

Dear 丶 2023-01-10 13:07 120阅读 0赞

## **项目中框架的体系结构** ##

![4738f375b08d7d172773da7083755f77.png][]

![6d738d4af00b5dfbf5edf7fb4e48fb66.png][]

Hibernate是一个**开放源代码的对象关系映射框架**，它对**JDBC进行了非常轻量级的对象封装**

## **hibernate的使用步骤** ##

A.下载hibernate 的jar包，并导入到项目中(http://hibernate.org/orm/)

B.创建数据库和表

C.配置核心配置文件hibernate.cfg.xml【这个文件有连接数据库的配置】

D.编写映射文件hibernate mapping(\*.hbm.xml),【声明对象如何关联数据库表字段】

E.调用hibernate的api

hibernate的调用：增删查改

@Test
        public void test1(){
         
            Configuration cfg = new Configuration().configure();
    
            SessionFactory factory = cfg.buildSessionFactory();
            Session session = factory.openSession();
    //        Transaction trans = session.getTransaction();
    //        trans.begin();
    //        查询
    //        User user = (User) session.get(User.class, 2);
            session.getTransaction().begin();//开启事务
    //        插入
    //        User user = new User();
    //        user.setUsername("ccc");
    //        user.setPassword("234");
    //        session.save(user);
    //        trans.commit();
    
    
    //        删除方法1
    //        User user = (User) session.get(User.class, 1);
    //        session.delete(user);
    //        删除方法2
    //        User user = new User();
    //        user.setUid(2);
    //        session.delete(user);
    
    //        修改方法1
    //        User user = (User) session.get(User.class, 1);
    //        user.setPassword("222");
    //        修改方法2
    //        User user = new User();
    //        user.setUid(1);
    //        user.setPassword("222");
    //        user.setUsername("bbb");
    //        session.update(user);
    
            session.getTransaction().commit();//事务提交
            session.close();
            factory.close();
        }

hibernate的调用：条件查询，分页查询 HQL语言

@Test
        public void test2(){
         
            Configuration cfg = new Configuration().configure();
    
            SessionFactory factory = cfg.buildSessionFactory();
            Session session = factory.openSession();
            //条件查询
    //        Query query =  session.createQuery("from User where username=? and password=?");
    //        query.setParameter(0,"bbb");
    //        query.setParameter(1,"222");
    //        User user = (User) query.uniqueResult();
    //        System.out.println(user);
    
            //分页查询
            Query query = session.createQuery("from User ");
            query.setFirstResult(2);//起始位置
            query.setMaxResults(2);//每页条数
            List<User> list = query.list();
            for (User user : list) {
         
                System.out.println(user);
            }
    
            session.close();
            factory.close();
        }

hibernate的调用：模糊查询，criteria

@Test
        public void test3() {
         
            Configuration cfg = new Configuration().configure();
    
            SessionFactory factory = cfg.buildSessionFactory();
            Session session = factory.openSession();
            Criteria criteria = session.createCriteria(User.class);
    //        criteria.add(Restrictions.eq("username","a"));
    //        criteria.add(Restrictions.eq("password","1"));
    //        System.out.println(criteria.uniqueResult());
    
    //        criteria.add(Restrictions.gt("id",3));
    
            criteria.add(Restrictions.like("username","%b%"));
            System.out.println(criteria.list());
    
        }

hibernate的调用：SQL语句查询

@Test
        public void test4() {
         
            Configuration cfg = new Configuration().configure();
    
            SessionFactory factory = cfg.buildSessionFactory();
            Session session = factory.openSession();
            SQLQuery query = session.createSQLQuery("SELECT * from t_user");
            List<Object[]> list = query.list();
            for (Object[] o : list) {
         
                for (Object o1 : o) {
         
                    System.out.println(o1);
                }
                System.out.println("----------");
            }
    
            session.close();
        }

映射文件配置：User.hbm.xml（放在domain下）

<!DOCTYPE hibernate-mapping PUBLIC 
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
    <hibernate-mapping>
    	<class name="com.gyf.hibernate.domain.User" table="t_user">
    		
    		<id name="uid" column="id">
    			
    			<generator class="native"></generator>
    		</id>
    		
    		<property name="username"></property>
    		<property name="password"></property>
    	</class>
    </hibernate-mapping>

核心配置文件：hibernate.cfg.xml（放src下）

<!DOCTYPE hibernate-configuration PUBLIC
    	"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    	"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
    
    <hibernate-configuration>
    	<session-factory>
    		
    		<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
    		<property name="hibernate.connection.url">jdbc:mysql:///hibernate_day1</property>
    		<property name="hibernate.connection.username">root</property>
    		<property name="hibernate.connection.password">123456</property>
    
    		
    		<property name="show_sql">true</property>
    		
    		
    		<property name="format_sql">true</property>
    		
    		
    		<property name="hibernate.connection.autocommit">true</property>
    		
    		
    		<property name="hibernate.current_session_context_class">thread</property>
    
    		
    		<property name="hibernate.hbm2ddl.auto">update</property>
    
    		
    		<property name="hiberante.dialect">org.hibernate.dialect.MySQL5Dialect</property>
    		
    		<mapping resource="com/gyf/hibernate/domain/User.hbm.xml" />
    	</session-factory>
    </hibernate-configuration>

[4738f375b08d7d172773da7083755f77.png]: /images/20221119/8fd80507e2c8441b8c9f45094d810847.png
[6d738d4af00b5dfbf5edf7fb4e48fb66.png]: /images/20221119/4f0ed4c235684b6caa6ffcd463fc565c.png