hibernate 基本配置文件及CRDU的操作和基本的HQL查询

<?xml version=‘1.0‘ encoding=‘utf-8‘?><!DOCTYPE hibernate-configuration PUBLIC ???????"-//Hibernate/Hibernate Configuration DTD//EN" ???????"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"><hibernate-configuration> ???<session-factory> ???????<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernate</property> ???????<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> ???????<property name="hibernate.connection.username">root</property> ???????<property name="hibernate.connection.password">123456</property> ???????<property name="hibernate.show_sql">true</property> ???????<property name="dialect">org.hibernate.dialect.MySQL5Dialect</property> ???????<property name="hibernate.hbm2ddl.auto">update</property> ???????<property name="hbm2ddl.auto">update</property> ???????<property name="format_sql">true</property>
//　　　　相关的类需要在这里添加配置 ???????<mapping resource="domain/UserEntity.hbm.xml"/> ???????<mapping class="domain.UserEntity"/> ???</session-factory></hibernate-configuration>

<?xml version=‘1.0‘ encoding=‘utf-8‘?><!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="domain.UserEntity" table="user" schema="hibernate"> ???????<id name="id" column="id" ?type="int" > ???????????<!-- 主键生成策略，尽量交个hibernate管理 --> ???????????<generator class="native"/> ???????</id> ???????<property name="username" column="username" type="java.lang.String"/> ???????<property name="password" column="password" type="java.lang.String"/> ???</class></hibernate-mapping>

public class test1 { ???SessionFactory sessionFactory; ???Session session; ???@Before ???public ?void ?before(){ ???????Configuration configuration = new Configuration(); ???????configuration.configure(); ???????sessionFactory = configuration.buildSessionFactory(); ???????session = sessionFactory.openSession(); ???} ???/** ????* 测试保存数据 save 和persist 都是保存 ????*/ ???@Test ???public void ?testSave(){ ???????Transaction transaction = session.beginTransaction(); ???????UserEntity userEntity = new UserEntity(); ???????userEntity.setUsername("余文辉"); ???????userEntity.setPassword("123456");// ???????session.save(userEntity); ???????session.persist(userEntity); ???????transaction.commit(); ???} ???@After ???public ?void ?after(){ ???????session.close(); ???????sessionFactory.close(); ???}}

** ????* 测试加载数据 get方法和load方法 ????* get获取时会立即向数据库发出sql语句，并拿到持久化对象 ????* load 方法在调用后悔获得一个代理类对象，该对象只保存了持久化类的id（印证持久化类必须要加一个id作为主键），直到使用该对象的非主键属性时，才会向数据库发出生气了语句 ????* getclass()方法 不会使用到该对象 ????*/ ???@Test ???public void testGet(){ ???????Transaction transaction = session.beginTransaction(); ???????UserEntity userEntity = (UserEntity) session.get(UserEntity.class,1); ???????System.out.println(userEntity.getClass()); ?/* class domain.UserEntity 这里是真正的UserEntity对象*/ ?????/* ?UserEntity user = (UserEntity) session.load(UserEntity.class, 1); ???????System.out.println(user.getClass()); *//* class domain.UserEntity_$$_jvst85e_0 这里是一个代理对象，该代理对象只保存了持久化类的id*/ ???}

/** ????* 测试更新方法 ????* 先查询到这个对象，再对这个对象进行更改 ????*/ ???@Test ???public ?void testUpdate(){ ???????Transaction transaction = session.beginTransaction(); ???????UserEntity user = (UserEntity) session.load(UserEntity.class, 1); ???????user.setUsername("余小四"); ???????session.update(user); ???????transaction.commit(); ???}

/** ????*测试删除方法 ????* 先查询到这个对象，再对这个对象进行删除 ????*/ ???@Test ???public void ?testDelete(){ ???????Transaction transaction = session.beginTransaction(); ???????UserEntity user = (UserEntity) session.load(UserEntity.class,3); ???????session.delete(user); ???????transaction.commit(); ???}

 　　/**
 ????* 获取单个对象
 ????*/
 ???@Test
 ???public void ?testHQL(){
 ???????String hql = "FROM UserEntity WHERE id = ? AND username = ?";
 ???????Query query = session.createQuery(hql);
// ?????占位参数从 0 开始，不是从 1 开始
 ???????query.setParameter(0,1).setParameter(1,"余小四");
// ???????获取集合中的 0 下标的对象
 ???????UserEntity user = (UserEntity) query.list().get(0);
 ???????System.out.println(user);
 ???}

 /** ????* 查询多个对象，获得一个List集合中 ????*/ ???@Test ???public ?void ?testHQLList(){// ???????FROM 后面不是表名，而是持久化类名 ???????String hql = "FROM UserEntity "; ???????Query query = session.createQuery(hql); ???????List<UserEntity> users = query.list(); ???????for (UserEntity user : users){ ???????????System.out.println(user.toString()); ???????} ???}