Vincent

任何獲得Matrix授權的網站，轉載請保留以下作者信息和鏈接：
作者：icess(作者的blog:http://blog.matrix.org.cn/page/icess)
關鍵字：Hibernate Validator

下面讓我們先看一個通常用 hbm.xml 映射文件的例子. 有3個類 .HibernateUtil.java 也就是 Hibernate文檔中推薦的工具類,Person.java 一個持久化的類, Test.java 測試用的類.都在test.hibernate 包中. 每個類的代碼如下:

01?package?test.hibernate;
02?
03?import?org.hibernate.HibernateException;
04?import?org.hibernate.Session;
05?import?org.hibernate.SessionFactory;
06?import?org.hibernate.cfg.Configuration;
07?
08?public?class?HibernateUtil?{
09???public?static?final?SessionFactory?sessionFactory;
10???
11???static?{
12?????try?{
13???????sessionFactory?=?new?Configuration()
14???????????????.configure()
15???????????????.buildSessionFactory();
16?????}?catch?(HibernateException?e)?{
17???????//?TODO?Auto-generated?catch?block
18???????
19???????e.printStackTrace();
20???????throw?new?ExceptionInInitializerError(e);
21?????}
22???}
23???
24???public?static?final?ThreadLocal<Session>?session?=?new?ThreadLocal<Session>();
25???
26???public?static?Session?currentSession()?throws?HibernateException?{
27?????Session?s?=?session.get();
28?????
29?????if(s?==?null)?{
30???????s?=?sessionFactory.openSession();
31???????session.set(s);
32?????}
33?????
34?????return?s;
35???}
36???
37???public?static?void?closeSession()?throws?HibernateException?{
38?????Session?s?=?session.get();
39?????if(s?!=?null)?{
40???????s.close();
41?????}
42?????session.set(null);
43???}
44?}

　

01?package?test.hibernate;
02?
03?import?java.util.LinkedList;
04?import?java.util.List;
05?
06?/**
07??*?
08??*/
09?
10?@SuppressWarnings("serial")
11?public?class?Person?implements?java.io.Serializable?{
12?
13???//?Fields
14?
15???private?Integer?id;
16?
17???private?String?name;
18?
19???private?String?sex;
20?
21???private?Integer?age;
22?
23???private?List?list?=?new?LinkedList();
24?
25???//?Collection?accessors
26?
27???public?List?getList()?{
28?????return?list;
29???}
30?
31???public?void?setList(List?list)?{
32?????this.list?=?list;
33???}
34?
35???/**?default?constructor?*/
36???public?Person()?{
37???}
38?
39???/**?constructor?with?id?*/
40???public?Person(Integer?id)?{
41?????this.id?=?id;
42???}
43?
44???//?Property?accessors
45?
46???public?Integer?getId()?{
47?????return?this.id;
48???}
49?
50???public?void?setId(Integer?id)?{
51?????this.id?=?id;
52???}
53?
54???public?String?getName()?{
55?????return?this.name;
56???}
57?
58???public?void?setName(String?name)?{
59?????this.name?=?name;
60???}
61?
62???public?String?getSex()?{
63?????return?this.sex;
64???}
65?
66???public?void?setSex(String?sex)?{
67?????this.sex?=?sex;
68???}
69?
70???public?Integer?getAge()?{
71?????return?this.age;
72???}
73?
74???public?void?setAge(Integer?age)?{
75?????this.age?=?age;
76???}
77?
78?}

　

01?/*
02??*?Created?on?
03??*?@author?
04??*/
05?package?test.hibernate;
06?
07?import?java.sql.SQLException;
08?
09?import?org.hibernate.FlushMode;
10?import?org.hibernate.HibernateException;
11?import?org.hibernate.Session;
12?import?org.hibernate.Transaction;
13?
14?public?class?Test?{
15???
16???public?static?void?main(String?[]?args)?{
17?????Session?s?=?HibernateUtil.currentSession();
18?????
19?????Transaction?tx?=?s.beginTransaction();????
20?????
21?//????Person?p?=?(Person)?s.load(Person.class,?1);
22?//????System.out.println(p.getName());
23?????Person?p?=?new?Person();
24?????
25?????p.setAge(19);
26?????p.setName("icerain");
27?????p.setSex("male");
28?????s.save(p);
29?????s.flush();
30?????/*
31?????Person?p2?=?(Person)?s.get(Person.class,?new?Integer(1));
32?????System.out.println(p2.getName());
33?????p2.setName("ice..");
34?????s.saveOrUpdate(p2);
35?????s.flush();
36?????Person?p3?=?(Person)?s.get(Person.class,?new?Integer(2));
37?????System.out.println(p3.getName());
38?????s.delete(p3);
39?????*/
40?????
41?????tx.commit();??
42?????try?{
43???????System.out.println(p.getName());
44?????}?catch?(Exception?e)?{
45???????//?TODO?Auto-generated?catch?block
46???????e.printStackTrace();
47?????}
48?????
49?????HibernateUtil.closeSession();
50???}
51?}

hibernate.cfg.xml 配置文件如下,利用mysql 數據庫.

<? xml version = "1.0" encoding = "UTF-8" ?>

<! DOCTYPE hibernate-configuration PUBLIC

"-//Hibernate/Hibernate Configuration DTD 3.0//EN"

"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd" >

< hibernate-configuration >

< session-factory >

< property name = "hibernate.connection.driver_class" > org.gjt.mm.mysql.Driver </ property >

< property name = "hibernate.connection.password" >你的數據庫密碼</ property >

< property name = "hibernate.connection.url" > jdbc:mysql://localhost/數據庫名 </ property >

< property name = "hibernate.connection.username" >用戶名</ property >

< property name = "hibernate.dialect" > org.hibernate.dialect.MySQLDialect </ property >

< property name = "show_sql" > true </ property >

< property name = "hibernate.transaction.factory_class" > org.hibernate.transaction.JDBCTransactionFactory </ property >

< property name = "hibernate.transaction.auto_close_session" > false </ property >

<property name="hibernate.hbm2ddl.auto">update</property>

< mapping resource = "test/hibernate/annotation/Person.hbm.xml" />

</ session-factory >

</ hibernate-configuration >

其中 配置了<property name="hibernate.hbm2ddl.auto">update</property>屬性 自動導入數據庫ddl.生產的ddl sql語句如下

create table person (id integer not null auto_increment, name varchar(255), sex varchar(255), age integer, person integer, primary key (id))

alter table person add index FKC4E39B5511C4A5C2 (person), add constraint FKC4E39B5511C4A5C2 foreign key (person) references person (id)

而Person.hbm.xml 文件如下:

<? xml version = "1.0" ?>

<! DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >

< hibernate-mapping >

< class name = "test.hibernate.Person" table = "person" >

< id name = "id" type = "integer" >

< column name = "id" />

< generator class = "native" ></ generator >

</ id >

< property name = "name" type = "string" >

< column name = "name" />

</ property >

< property name = "sex" type = "string" >

< column name = "sex" />

</ property >

< property name = "age" type = "integer" >

< column name = "age" />

</ property >

< bag name = "list" cascade = "all" >

< key column = "person" ></ key >

< one-to-many class = "test.hibernate.Person" />

</ bag >

</ class >

</ hibernate-mapping >

下面讓我們看看利用 Hibernate Annotations 如何做,只要三個類 不再需要 hbm.xml配置文件:

還要把用到的兩個jar文件 放入的類路徑中. 具體如何做,請參考? Hibernate Annotations 中文文檔

http://hb.6644.net

HibernateUtil.java 也就是 Hibernate文檔中推薦的工具類,Person.java 一個持久化的類, Test.java 測試用的類.都在test.hibernate.annotation 包中. 每個類的代碼如下:

01?package?test.hibernate.annotation;
02?
03?import?org.hibernate.HibernateException;
04?import?org.hibernate.Session;
05?import?org.hibernate.SessionFactory;
06?import?org.hibernate.cfg.AnnotationConfiguration;
07?import?org.hibernate.cfg.Configuration;
08?
09?public?class?HibernateUtil?{
10???public?static?final?SessionFactory?sessionFactory;
11???
12???static?{
13?????try?{
14???????sessionFactory?=?new?AnnotationConfiguration()?? //注意: 建立 SessionFactory于前面的不同
15?????????????????.addPackage("test.hibernate.annotation")
16?????????????????.addAnnotatedClass(Person.class)
17?????????????????
18?????????????????.configure()
19?????????????????.buildSessionFactory();
20?????????//new?Configuration().configure().buildSessionFactory();
21?????}?catch?(HibernateException?e)?{
22???????//?TODO?Auto-generated?catch?block
23???????
24???????e.printStackTrace();
25???????throw?new?ExceptionInInitializerError(e);
26?????}
27???}
28???
29???public?static?final?ThreadLocal<Session>?session?=?new?ThreadLocal<Session>();
30???
31???public?static?Session?currentSession()?throws?HibernateException?{
32?????Session?s?=?session.get();
33?????
34?????if(s?==?null)?{
35???????s?=?sessionFactory.openSession();
36???????session.set(s);
37?????}
38?????
39?????return?s;
40???}
41???
42???public?static?void?closeSession()?throws?HibernateException?{
43?????Session?s?=?session.get();
44?????if(s?!=?null)?{
45???????s.close();
46?????}
47?????session.set(null);
48???}
49?}

　

01?package?test.hibernate.annotation;
02?
03?import?java.util.LinkedList;
04?import?java.util.List;
05?
06?import?javax.persistence.AccessType;
07?import?javax.persistence.Basic;
08?import?javax.persistence.Entity;
09?import?javax.persistence.GeneratorType;
10?import?javax.persistence.Id;
11?import?javax.persistence.OneToMany;
12?import?javax.persistence.Table;
13?import?javax.persistence.Transient;
14?
15?/**
16??*?
17??*/
18?
19?@SuppressWarnings("serial")
20?@Entity(access?=?AccessType.PROPERTY) //定義該類為實體類
21?@Table?? //映射表
22?public?class?Person?implements?java.io.Serializable?{
23?
24???//?Fields
25?
26???private?Integer?id;
27?
28???private?String?name;
29?
30???private?String?sex;
31?
32???private?Integer?age;
33?
34???private?List?list?=?new?LinkedList();
35?
36???//?Constructors
37???/**?default?constructor?*/
38???public?Person()?{
39???}
40?
41???/**?constructor?with?id?*/
42???public?Person(Integer?id)?{
43?????this.id?=?id;
44???}
45?
46???//?Property?accessors
47???@Id
48???public?Integer?getId()?{
49?????return?this.id;
50???}
51?
52???public?void?setId(Integer?id)?{
53?????this.id?=?id;
54???}
55?
56???@Basic
57???public?String?getName()?{
58?????return?this.name;
59???}
60?
61???public?void?setName(String?name)?{
62?????this.name?=?name;
63???}
64?
65???@Basic
66???public?String?getSex()?{
67?????return?this.sex;
68???}
69?
70???public?void?setSex(String?sex)?{
71?????this.sex?=?sex;
72???}
73?
74???@Basic
75???public?Integer?getAge()?{
76?????return?this.age;
77???}
78?
79???public?void?setAge(Integer?age)?{
80?????this.age?=?age;
81???}
82???@Transient? //由于本例不打算演示集合映射 所有聲明該屬性為 Transient?
83???public?List?getList()?{
84?????return?list;
85???}
86?
87???public?void?setList(List?list)?{
88?????this.list?=?list;
89???}
90?
91?}

注意該實體類中的屬性都使用了默認值.

Test.java 代碼同上

不需要了 hbm.xml 映射文件, 是不是簡單了一些 .給人認為簡化了一些不是主要目的.主要是可以了解一下 EJB3 的持久化機制 ,提高一下開發效率才是重要的.

好了 .本例就完了 . 感覺怎么樣了 .歡迎你來批批.

PS:

生成的數據庫表 和 程序執行后的 數據庫情況如下

mysql> describe person;
+--------+--------------+------+-----+---------+----------------+
| Field? | Type???????? | Null | Key | Default |????????? Extra |
+--------+--------------+------+-----+---------+----------------+
| id???? | int(11)????? | NO?? | PRI | NULL??? | auto_increment |
| name?? | varchar(255) | YES? |???? | NULL??? |??????????????? |
| sex??? | varchar(255) | YES? |???? | NULL??? |??????????????? |
| age??? | int(11)????? | YES? |???? | NULL??? |??????????????? |
| person | int(11)????? | YES? | MUL | NULL??? |??????????????? |
+--------+--------------+------+-----+---------+----------------+
5 rows in set (0.00 sec)

mysql> select * from person;
+----+---------+------+------+--------+
| id | name??? |? sex |? age | person |
+----+---------+------+------+--------+
|? 1 | icerain | male |?? 19 |?? NULL |
+----+---------+------+------+--------+
1 row in set (0.03 sec)