Hibernate学习:基本介绍+作用+配置

- 日理万妓 2022-03-01 00:28 208阅读 0赞

1.简介与原理  
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，它将POJO与数据库表建立映射关系，是一个全自动的orm框架，hibernate可以自动生成SQL语句，自动执行  
![百度百度百度][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29MZW5nWXVlSHVu_size_16_color_FFFFFF_t_70]2.配置xml  
项目目录如下  
![百度百度百度][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29MZW5nWXVlSHVu_size_16_color_FFFFFF_t_70 1]先导入依赖pom.xml  
其中slf4j和hibernate是一定要一起导入的

<dependency>
    			<groupId>junit</groupId>
    			<artifactId>junit</artifactId>
    			<version>4.0</version>
    			<scope>test</scope>
    		</dependency>
    		
    		
    		<dependency>
    			<groupId>org.hibernate</groupId>
    			<artifactId>hibernate-core</artifactId>
    			<version>4.0.1.Final</version>
    		</dependency>
    		
    
    		
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-jdbc</artifactId>
    			<version>4.0.0.RELEASE</version>
    		</dependency>
    		<dependency>
    			<groupId>com.oracle</groupId>
    			<artifactId>jdbc</artifactId>
    			<version>11.2.0.1.0</version>
    		</dependency>
    		<dependency>
    			<groupId>commons-dbcp</groupId>
    			<artifactId>commons-dbcp</artifactId>
    			<version>1.4</version>
    		</dependency>
    		
    		
    		
    		<dependency>
    			<groupId>org.slf4j</groupId>
    			<artifactId>slf4j-api</artifactId>
    			<version>1.7.26</version>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.slf4j</groupId>
    			<artifactId>slf4j-log4j12</artifactId>
    			<version>1.7.26</version>
    			<scope>test</scope>
    		</dependency>

hibernate.cfg.xml配置

<session-factory>
    		
    		<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
    		<property name="connection.url">jdbc:oracle:thin:@localhost:1521:orcl</property>
    		<property name="connection.username">scott</property>
    		<property name="connection.password">tiger</property>
    		
    		
    
    
    		
    		<property name="dialect">org.hibernate.dialect.OracleDialect</property>
    		
    		
    
    
    		
    
    		<property name = "format_sql">true</property>
    		
    		
    		<property name="show_sql">true</property>
    		
    		
    		<property name="hbm2ddl.auto">update</property>
    		<mapping resource="hbm/Teacher.hbm.xml" />
    		<mapping resource="hbm/Student.hbm.xml" />
    	</session-factory>

Student.hbm.xml配置

Teacher.hbm.xml

log4j.properties

log4j.rootLogger = info,a
    
    log4j.appender.a = org.apache.log4j.ConsoleAppender
    log4j.appender.a.Target = System.err
    log4j.appender.a.layout = org.apache.log4j.SimpleLayout

3.下面是具体代码  
dao层

public class DaoImpl implements Dao{
    	Session session = null;
    	
    	/**
    	 * 获取session
    	 * */
    	public Session getSession() {
    		Configuration cfg = new Configuration().configure();//配置cfg
    		@SuppressWarnings({})
    		SessionFactory sessionFactory = cfg.buildSessionFactory();
    		session = sessionFactory.openSession();//打开session
    		return session;
    	}
    	
    	/**
    	 * 添加学生信息
    	 * */
    	public void addStudent(Student student) {
    		System.out.println("开始添加");
    		session = getSession();
    		Transaction tsa = session.beginTransaction();//开启事务
    		try {
    			session.save(student);
    			tsa.commit();
    		}catch(Exception e) {
    			e.printStackTrace();
    			tsa.rollback();//回滚
    		}finally {
    			session.close();
    		}
    	}
    	
    	/**
    	 * 查找学生信息列表
    	 * */
    	public void findStudent() {
    		session = getSession();
    		System.out.println("开始查找表");
    		try {
    			List<Student> list = session.createQuery("from Student").list();//查询数据库获得结果集
    			for(Student student:list) {//遍历列表输出信息
    				System.out.println(student.getName());
    			}
    		}catch(Exception e) {
    			e.printStackTrace();
    			session.close();//关闭session
    		}
    	}
    	
    	/**
    	 * 由id查找学生信息
    	 * */
    	public void findStudentById(int id) {
    		session = getSession();
    		System.out.println("开始id查找");
    		try {
    			Student student = (Student) session.get(Student.class, id);//查询数据库获得结果
    			System.out.println(student.getName());//输出信息
    		}catch(Exception e) {
    			e.printStackTrace();
    		}finally {
    			session.close();//关闭session
    		}
    	}
    	
    	/**
    	 * 有名字查询学生信息
    	 * */
    	public void findStudentByName(String name) {
    		session = getSession();
    		System.out.println("开始name查找");
    		String hql = "from Student where name = :name";//创建hql
    		try {
    			Query query = session.createQuery(hql);
    			query.setString("name", name);
    			Student student = (Student) query.uniqueResult();
    			System.out.println(student.getId());
    		}catch(Exception e) {
    			e.printStackTrace();	
    		}finally {
    			session.close();
    		}
    	}
    }

测试类
    	@Test
    	public void asd() {
    		System.out.println(1);
    		Student student = new Student();
    		Teacher teacher = new Teacher();
    //		student.setName("gz");
    //		teacher.setName("zxs");
    //		teacher.setStudent(student);
    		DaoImpl daoImpl = new DaoImpl();
    //		daoImpl.addStudent(student);
    //		daoImpl.findStudent();
    //		daoImpl.findStudentById(7);
    //		daoImpl.findStudentByName("gz");
    		Session session = daoImpl.getSession();
    //		session.save(teacher);
    //		session.beginTransaction().commit();
    		Teacher t = (Teacher) session.load(Teacher.class, 4);
    		System.out.println(t.getId()+t.getName()+t.getStudent().getName());
    		session.close();
    	}

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