Hibernate学习笔记

1.创建一个用于测试的mysql数据库，数据库名为testdb

2.在testdb中创建一个测试表user,结构如下：

mysql> desc user;+----------+--------------+------+-----+---------+----------------+| Field | Type | Null | Key | Default | Extra |+----------+--------------+------+-----+---------+----------------+| id | int(11) | NO | PRI | NULL | auto_increment || name | varchar(100) | YES | | NULL | || address | varchar(100) | YES | | NULL | || password | varchar(100) | YES | | NULL | |+----------+--------------+------+-----+---------+----------------+4 rows in set (0.00 sec)

  

3.创建一个和user表字段对应的Bean  

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1. public class User { 
2.     private int id; 
3.     private String name; 
4.     private String address; 
5.     private String password; 
6.         setter 和 getter方法略 
7. } 

4.定义一个操作User表的Dao接口IUserDao

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1. public interface IUserDao { 
2.     public void add(User user); 
3.      
4.     public void delete(int uid); 
5.      
6.     public void update(User user); 
7.      
8.     public User findById(int uid); 
9.      
10.     public List<User> getUserListByAddress(String address);    
11. } 

5.定义IUserDao的实现类UserDao类，此类要实现IUserDao接口同时继承HibernateDaoSupport抽象类，以获取SessionFactory

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1. public class UserDao extends HibernateDaoSupport  implements IUserDao { 
2.  
3.     @Override 
4.     public void add(User user) { 
5.         this.getHibernateTemplate().save(user); 
6.     } 
7.  
8.     @Override 
9.     public void delete(int uid) { 
10.         User user=new User(); 
11.         user.setId(uid); 
12.         this.getHibernateTemplate().delete(user); 
13.     } 
14.  
15.     @Override 
16.     public User findById(int uid) { 
17.         return (User)this.getHibernateTemplate().get(User.class,uid); 
18.     } 
19.  
20.     @Override 
21.     public List<User> getUserListByAddress(String address) { 
22.         return null; 
23.     } 
24.  
25.     @Override 
26.     public void update(User user) { 
27.         this.getHibernateTemplate().update(user); 
28.     } 
29.  
30. } 
    
    

6.定义User.hbm.xml，内容如下：

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1. <?xmlversion="1.0"encoding="utf-8"?> 
2. <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 
3. "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> 
4. <hibernate-mapping> 
5.     <classname="com.hndy.demo.hibernate.jdbc.bean.User"table="user">        
6.         <idname="id"column="id"type="java.lang.Integer"> 
7.              <generatorclass="native"/> 
8.         </id> 
9.         <propertyname="name"type="java.lang.String"> 
10.             <columnname="name"length="100"/> 
11.         </property> 
12.  
13.         <propertyname="address"type="java.lang.String"> 
14.             <columnname="address"length="100"/> 
15.         </property> 
16.          
17.         <propertyname="password"type="java.lang.String"> 
18.             <columnname="password"length="100"/> 
19.         </property>         
20.     </class> 
21. </hibernate-mapping> 

其中property name与类中的属性一一对应，type是属性的类型，column name是类的属于对应的字段名，length表示字段的长度

这里需要说明一下id的创建问题，有这几种方法产生主键

(1)identity：用于MySql数据库。特点：递增
    对于MySql数据库使用递增序列时需要在建表时对主键指定为auto_increment属性。

(2)native：跨数据库时使用，由底层方言产生。
    Default.sequence为hibernate_sequence
   使用native时Hibernate默认会去查找Oracle中的hibernate_sequence序列。如果Oracle中没有该序列，连Oracle数据库时会报错。

(3)sequence：用于Oracle数据库

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1. <idname="id"column="id"> 
2.    <generatorclass="sequence"> 
3.      <paramname="sequence">序列名</param> 
4.    </generator> 
5. </id> 

(4)hilo：通过高低位合成id，先建表hi_value，再建列next_value。必须要有初始值。

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1. <idname="id"column="id"> 
2.     <generatorclass="hilo"> 
3.       <paramname="table">high_val</param> 
4.        <paramname="column">nextval</param> 
5.       <paramname="max_lo">5</param> 
6.     </generator> 
7. </id> 

(5)assigned：用户自定义id;

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1. <idname="id"column="id"> 
2.    <generatorclass="assigned"/> 
3. </id> 

测试发现当Id设置为自动增长时，使用identity 和 native没有本质上的区别

(6)uuid

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1. <id  name="Id"column="id" type="string"> 
2.     <generator  class="uuid"/> 
3. </id> 

uuid可以产生36个16进制字符串，当表的ID字段设置为字符类型并且非自动增长是时，使用uuid产生逻辑主键非常有用

7.创建测试类TestCase_UserDao

A.测试getHibernateTemplate().save()方法

在本例中其实还配置了Spring和Hibernate的相关参数，在此不再解释了

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1. public staticvoid testHibernate_add(){ 
2.         SystemBeans.initialize(); 
3.         IUserDao dao = (IUserDao)SystemBeans.getBean("userDao"); 
4.         User user = new User(); 
5.         user.setName("Wangwu3"); 
6.         user.setAddress("ShangHai"); 
7.         user.setPassword("mypassword"); 
8.         dao.add(user);       
9. } 

运行测试类的testHibernate_add()方法，部分输出信息如下：

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1. Opening Hibernate Session 
2. opened session at timestamp: 13267000514 
3. executing identity-insert immediately 
4. about to open PreparedStatement (open PreparedStatements: 0, globally: 0) 
5. opening JDBC connection 
6. insert into user (name, address, password) values (?, ?, ?) 
7. Hibernate: insert into user (name, address, password) values (?, ?, ?) 
8. Natively generated identity: 10 
9. about to close PreparedStatement (open PreparedStatements: 1, globally: 1) 
10. Eagerly flushing Hibernate session 
11. processing flush-time cascades 
12. dirty checking collections 
13. Flushed: 0 insertions, 0 updates, 0 deletions to 1 objects 
14. Flushed: 0 (re)creations, 0 updates, 0 removals to 0 collections 
15. listing entities: 
16. com.ynyd.demo.hibernate.jdbc.bean.User{id=10, address=ShangHai, name=Wangwu3, password=mypassword} 
17. Closing Hibernate Session 

可以看到具体的执行顺序
第1 行开启Hibernate Session
第5 行打开JDBC connection
第6 行输出的是拼接好的sql
第8 行输出的是产生好的一个主键值10
第9 行执行完SQL
第16行输出User类的各个属性值，可以发现id=10
第17行关闭了Hibernate Session

B.测试getHibernateTemplate().delete()方法

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1. public staticvoid testHibernate_delete(){ 
2.     SystemBeans.initialize(); 
3.     IUserDao dao = (IUserDao)SystemBeans.getBean("userDao"); 
4.     dao.delete(11); 
5. } 

运行测试类的testHibernate_delete()方法，部分输出信息如下：

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1. Opening Hibernate Session 
2. opened session at timestamp: 13267028259 
3. Eagerly flushing Hibernate session 
4. processing flush-time cascades 
5. dirty checking collections 
6. Flushed: 0 insertions, 0 updates, 1 deletions to 1 objects 
7. Flushed: 0 (re)creations, 0 updates, 0 removals to 0 collections 
8. listing entities: 
9. com.ynyd.demo.hibernate.jdbc.bean.User{id=11, address=null, name=null, password=null} 
10. about to open PreparedStatement (open PreparedStatements: 0, globally: 0) 
11. opening JDBC connection 
12. delete from user where id=? 
13. Hibernate: delete from user where id=? 
14. Executing batch size: 1 
15. about to close PreparedStatement (open PreparedStatements: 1, globally: 1) 
16. Closing Hibernate Session 
17. releasing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)] 

C.测试HibernateDaoSupport.getHibernateTemplate().update()方法,修改表记录

查看当前的user表数据情况

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1. mysql> select *fromuser; 
2. +----+---------+----------+------------+ 
3. | id | name    | address  |password   | 
4. +----+---------+----------+------------+ 
5. | 12 | Wangwu3 | ShangHai | mypassword | 
6. +----+---------+----------+------------+ 
7. 1 row in set (0.01 sec) 

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1. public staticvoid testHibernate_update(){ 
2.     SystemBeans.initialize(); 
3.     IUserDao dao = (IUserDao)SystemBeans.getBean("userDao"); 
4.     User user = new User(); 
5.     user.setId(12); 
6.     user.setName("Rooke"); 
7.     user.setAddress("Shangdi BeiJing"); 
8.     user.setPassword("123456"); 
9.     dao.update(user); 
10. } 

运行测试类的testHibernate_update()方法，部分输出信息如下：

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1. Opening Hibernate Session 
2. opened session at timestamp: 13267033472 
3. Eagerly flushing Hibernate session 
4. processing flush-time cascades 
5. dirty checking collections 
6. Flushed: 0 insertions, 1 updates, 0 deletions to 1 objects 
7. Flushed: 0 (re)creations, 0 updates, 0 removals to 0 collections 
8. listing entities: 
9. com.hnyd.demo.hibernate.jdbc.bean.User{id=12, address=Shangdi BeiJing, name=Rooke, password=123456} 
10. about to open PreparedStatement (open PreparedStatements: 0, globally: 0) 
11. opening JDBC connection 
12. update user set name=?, address=?, password=? where id=? 
13. Hibernate: update user set name=?, address=?, password=? where id=? 
14. Executing batch size: 1 
15. about to close PreparedStatement (open PreparedStatements: 1, globally: 1) 
16. Closing Hibernate Session 
17. releasing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)] 
18. transaction completed on session with on_close connection release mode; be sure to close the session to release JDBC resources! 

C.测试HibernateDaoSupport.getHibernateTemplate().get()方法

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1. public staticvoid testHibername_find(){ 
2.     SystemBeans.initialize(); 
3.     IUserDao dao = (IUserDao)SystemBeans.getBean("userDao"); 
4.     User u = dao.findById(12); 
5.     System.out.println(u.getId()); 
6.     System.out.println(u.getName()); 
7.     System.out.println(u.getAddress()); 
8.     System.out.println(u.getPassword()); 
9. } 

运行测试类的testHibernate_find()方法，部分输出信息如下：

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1. Opening Hibernate Session 
2. opened session at timestamp: 13267035305 
3. loading entity: [com.ynyd.demo.hibernate.jdbc.bean.User#12] 
4. about to open PreparedStatement (open PreparedStatements: 0, globally: 0) 
5. opening JDBC connection 
6. select user0_.id as id0_0_, user0_.name as name0_0_, user0_.address as address0_0_,  
7. user0_.password as password0_0_ from user user0_ where user0_.id=? 
8. Hibernate: select user0_.id as id0_0_, user0_.name as name0_0_, user0_.address as address0_0_,  
9. user0_.password as password0_0_ from user user0_ where user0_.id=? 
10. about to open ResultSet (open ResultSets: 0, globally: 0) 
11. result row: EntityKey[com.ynyd.demo.hibernate.jdbc.bean.User#12] 
12. about to close ResultSet (open ResultSets: 1, globally: 1) 
13. about to close PreparedStatement (open PreparedStatements: 1, globally: 1) 
14. resolving associations for [com.ynyd.demo.hibernate.jdbc.bean.User#12] 
15. done materializing entity [com.ynyd.demo.hibernate.jdbc.bean.User#12] 
16. initializing non-lazy collections 
17. done entity load 
18. transaction completed on session with on_close connection release mode; be sure to close the session to release JDBC resources! 
19. Eagerly flushing Hibernate session 
20. processing flush-time cascades 
21. dirty checking collections 
22. Flushed: 0 insertions, 0 updates, 0 deletions to 1 objects 
23. Flushed: 0 (re)creations, 0 updates, 0 removals to 0 collections 
24. listing entities: 
25. com.ynyd.demo.hibernate.jdbc.bean.User{id=12, address=Shangdi BeiJing, name=Rooke, password=123456} 
26. Closing Hibernate Session 
27. releasing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)] 
28. transaction completed on session with on_close connection release mode; be sure to close the session to release JDBC resources! 
29. 12 
30. Rooke 
31. Shangdi BeiJing 
32. 123456 
33. Closing org.springframework.context.support.FileSystemXmlApplicationContext@b169f8: startup date [Mon Jan 16 16:45:29 CST 2012];  
34. root of context hierarchy 

C.测试HibernateDaoSupport.getHibernateTemplate().find()方法,查询user表所有记录

IUserDao接口增加
public List<User> getAllUsers();

UserDao方法增加
public List<User> getAllUsers(){

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1. return (List<User>)this.getHibernateTemplate().find("from User"); 

测试类增加
public static void testHibername_findAll(){

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1.     SystemBeans.initialize(); 
2.     IUserDao dao = (IUserDao)SystemBeans.getBean("userDao"); 
3.     List<User> list = dao.getAllUsers(); 
4.     for(User u:list){ 
5.         System.out.println(u.toString());            
6.     } 
7. } 

查询user表的数据：

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1. mysql> select *fromuser; 
2. +----+----------+----------+----------+ 
3. | id | name     | address  |password | 
4. +----+----------+----------+----------+ 
5. | 15 | zhangsan | Beijing  | 123456   | 
6. | 16 | lisi     | Shanghai | 123456   | 
7. | 17 | wangwu   | Shanghai | 123456   | 
8. +----+----------+----------+----------+ 
9. 3 rows inset (0.01 sec) 

执行测试方法后结果如下：

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1. name:zhangsan,password:123456,address:Beijing 
2. name:lisi,password:123456,address:Shanghai 
3. name:wangwu,password:123456,address:Shanghai 

C.测试HibernateDaoSupport.getHibernateTemplate().find()方法,查询user表指定条件的记录

IUserDao接口增加

public User findByName(String name);

UserDao增加

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1. public User findByName(String name){ 
2.     List<User> list = (List<User>)this.getHibernateTemplate().find(String.format("from User u where u.name='%s'", name)); 
3.     if (list.size()>0){ 
4.         return list.get(0); 
5.     } 
6.     return null; 
7. } 

find()方法支持HQL，并且返回的结果是个集合类型，因此需要从集合里面取出元素再返回

测试类增加

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1. public staticvoid testHibername_findByName(){ 
2.     SystemBeans.initialize(); 
3.     IUserDao dao = (IUserDao)SystemBeans.getBean("userDao"); 
4.     User u = dao.findByName("zhangsan"); 
5.     System.out.println(u.toString()); 
6. } 

执行结果如下：

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1. name:zhangsan,password:123456,address:Beijing