hibernate3学习笔记(四)｜增删改查

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接前面的例子：http://blog.csdn.net/kunshan_shenbin/archive/2008/09/02/2864883.aspx

测试代码：

package com.hb3.pack_01;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import com.hb3.pack_01.model.User;
public class BusinessService {
    public static void main(String[] args) {
        
        Configuration config = new Configuration().configure();
        SessionFactory sessionFactory = config.buildSessionFactory();      
        Session session = sessionFactory.openSession();
        
        //insert 
        User user = new User();
        user.setName("chenyan");
        //user.setAge(new Integer(23));
        Transaction tx = session.beginTransaction();
        session.save(user);
        tx.commit();
        
        //get 
        user = (User) session.get(User.class, user.getId());
        System.out.println(user.getAge());
        
        //update 
        user.setAge(new Integer(24));
        tx= session.beginTransaction(); 
        session.update(user);
        tx.commit();
        //load 
        user = (User) session.load(User.class, user.getId());
        System.out.println(user.getAge());
        
        //delete 
        tx = session.beginTransaction();
        session.delete(user);
        tx.commit();
        
        session.close();
        sessionFactory.close();
    }
}

执行结果：

11:50:50,750 WARN ConfigurationFactory:127 - No configuration found. Configuring ehcache from ehcache-failsafe.xml found in the classpath: jar:file:/D:/Java/MyEclipse%206.0/workspace/hb3demo/ehcache-1.2.3.jar!/ehcache-failsafe.xml
11:50:51,156 WARN EhCacheProvider:93 - Could not find configuration [org.hibernate.cache.UpdateTimestampsCache]; using defaults.
11:50:51,171 WARN EhCacheProvider:93 - Could not find configuration [org.hibernate.cache.StandardQueryCache]; using defaults.
Hibernate: insert into user (name, age) values (?, ?)
null
Hibernate: update user set name=?, age=? where id=?
24

修改User.hbm.xml文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="com.hb3.pack_01.model.User" table="user" 
        dynamic-insert="true" 
        dynamic-update="true"   
    >
        <id name="id" column="id" type="java.lang.Integer">
            <generator class="native" />
        </id>
        
        <property name="name" column="name" type="java.lang.String" />
        
        <property name="age" column="age" type="java.lang.Integer" />
    </class>
</hibernate-mapping>

运行结果如下：

12:46:32,062 WARN ConfigurationFactory:127 - No configuration found. Configuring ehcache from ehcache-failsafe.xml found in the classpath: jar:file:/D:/Java/MyEclipse%206.0/workspace/hb3demo/ehcache-1.2.3.jar!/ehcache-failsafe.xml
12:46:32,468 WARN EhCacheProvider:93 - Could not find configuration [org.hibernate.cache.UpdateTimestampsCache]; using defaults.
12:46:32,500 WARN EhCacheProvider:93 - Could not find configuration [org.hibernate.cache.StandardQueryCache]; using defaults.
Hibernate: insert into user (name) values (?)
null
Hibernate: update user set age=? where id=?
24
Hibernate: delete from user where id=?

可见：

dynamic-insert和dynamic-update设成true后，分别表示生成的SQL中只插入非空字段以及只修改改变过的字段。

另外,hibernate还提供了saveOrUpdate()方法，因为这个方法很容易出错，故在后续章节着重讲述。

关于查询：

package com.hb3.pack_01;
import java.util.Iterator;
import java.util.List;
import org.hibernate.Criteria;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.criterion.Restrictions;
import com.hb3.pack_01.model.User;
public class BusinessService {
    public static void main(String[] args) {
        
        Configuration config = new Configuration().configure();
        SessionFactory sessionFactory = config.buildSessionFactory();      
        Session session = sessionFactory.openSession();
        
        Criteria criteria = session.createCriteria(User.class);
        List<?> users = criteria.list();
        Iterator<?> iterator = users.iterator();
        System.out.println("id /t name/age");
        while (iterator.hasNext()) {
            User user = (User) iterator.next();
            System.out.println(user.getId() + " /t " + user.getName() + "/" + user.getAge());
        }
        
        //criteria.add(Expression.eq("name", "shenbin")); 
        criteria.add(Restrictions.eq("name", "shenbin"));
        users = criteria.list();
        iterator = users.iterator();
        System.out.println("id /t name/age");
        while (iterator.hasNext()) {
            User user = (User) iterator.next();
            System.out.println(user.getId() + " /t " + user.getName() + "/" + user.getAge());
        }
        
        System.out.println("====================================================");
        
        Query query = session.createQuery("from User");
        users = query.list();
        iterator = users.iterator();
        System.out.println("id /t name/age");
        while (iterator.hasNext()) {
            User user = (User) iterator.next();
            System.out.println(user.getId() + " /t " + user.getName() + "/" + user.getAge());
        }
        
        query = session.createQuery("from User user where user.name like ?");
        query.setParameter(0, "shenbin");
        users = query.list();
        iterator = users.iterator();
        System.out.println("id /t name/age");
        while (iterator.hasNext()) {
            User user = (User) iterator.next();
            System.out.println(user.getId() + " /t " + user.getName() + "/" + user.getAge());
        }
        session.close();
        sessionFactory.close();
    }
}

执行结果：

13:05:43,031 WARN ConfigurationFactory:127 - No configuration found. Configuring ehcache from ehcache-failsafe.xml found in the classpath: jar:file:/D:/Java/MyEclipse%206.0/workspace/hb3demo/ehcache-1.2.3.jar!/ehcache-failsafe.xml
13:05:43,453 WARN EhCacheProvider:93 - Could not find configuration [org.hibernate.cache.UpdateTimestampsCache]; using defaults.
13:05:43,484 WARN EhCacheProvider:93 - Could not find configuration [org.hibernate.cache.StandardQueryCache]; using defaults.
Hibernate: select this_.id as id0_0_, this_.name as name0_0_, this_.age as age0_0_ from user this_
id name/age
1 shenbin/29
2 chenyan/24
3 chenyan/24
4 chenyan/24
Hibernate: select this_.id as id0_0_, this_.name as name0_0_, this_.age as age0_0_ from user this_ where this_.name=?
id name/age
1 shenbin/29
================================================
Hibernate: select user0_.id as id0_, user0_.name as name0_, user0_.age as age0_ from user user0_
id name/age
1 shenbin/29
2 chenyan/24
3 chenyan/24
4 chenyan/24
Hibernate: select user0_.id as id0_, user0_.name as name0_, user0_.age as age0_ from user user0_ where user0_.name like ?
id name/age
1 shenbin/29

以上分别演示了使用Criteria对SQL的分装以及透过HQL来进行查询。

注意：

代码中如下部分

//criteria.add(Expression.eq("name", "shenbin"));
criteria.add(Restrictions.eq("name", "shenbin"));

在hibernate3.3以后的版本，可能Expression类会被废除，为了保证代码的向后兼容，请使用Restrictions替代。