Spring DAO之JDBC
Spring提供的DAO(数据访问对象)支持主要的目的是便于以标准的方式使用不同的数据访问技术， 如JDBC，Hibernate或者JDO等。它不仅可以让你方便地在这些持久化技术间切换， 而且让你在编码的时候不用考虑处理各种技术中特定的异常。
为了便于以一种一致的方式使用各种数据访问技术，如JDBC、JDO和Hibernate， Spring提供了一套抽象DAO类供你扩展。这些抽象类提供了一些方法，通过它们你可以 获得与你当前使用的数据访问技术相关的数据源和其他配置信息。
Dao支持类：
JdbcDaoSupport - JDBC数据访问对象的基类。 需要一个DataSource，同时为子类提供 JdbcTemplate。
HibernateDaoSupport - Hibernate数据访问对象的基类。 需要一个SessionFactory，同时为子类提供 HibernateTemplate。也可以选择直接通过 提供一个HibernateTemplate来初始化， 这样就可以重用后者的设置，例如SessionFactory， flush模式，异常翻译器（exception translator）等等。
JdoDaoSupport - JDO数据访问对象的基类。 需要设置一个PersistenceManagerFactory， 同时为子类提供JdoTemplate。
JpaDaoSupport - JPA数据访问对象的基类。 需要一个EntityManagerFactory，同时 为子类提供JpaTemplate。
本节主要讨论Sping对JdbcDaoSupport的支持。
下面是个例子：
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drop table if exists user;
/*==============================================================*/
/* Table: user */
/*==============================================================*/
create table user
(
id bigint AUTO_INCREMENT not null,
name varchar(24),
age int,
primary key (id)
);
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public class User {
private Integer id;
private String name;
private Integer age;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
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/**
* Created by IntelliJ IDEA.<br>
* <b>User</b>: leizhimin<br>
* <b>Date</b>: 2008-4-22 15:34:36<br>
* <b>Note</b>: DAO接口
*/
public interface IUserDAO {
public void insert(User user);
public User find(Integer id);
}
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
/**
* Created by IntelliJ IDEA.<br>
* <b>Note</b>: 基类DAO，提供了数据源注入
*/
public class BaseDAO {
private DataSource dataSource;
public DataSource getDataSource() {
return dataSource;
}
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
public Connection getConnection() {
Connection conn = null;
try {
conn = dataSource.getConnection();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
}
/**
* Created by IntelliJ IDEA.<br>
* <b>User</b>: leizhimin<br>
* <b>Date</b>: 2008-4-22 15:36:04<br>
* <b>Note</b>: DAO实现
*/
public class UserDAO extends BaseDAO implements IUserDAO {
public JdbcTemplate getJdbcTemplate(){
return new JdbcTemplate(getDataSource());
}
public void insert(User user) {
String name = user.getName();
int age = user.getAge().intValue();
// jdbcTemplate.update("INSERT INTO user (name,age) "
// + "VALUES('" + name + "'," + age + ")");
String sql = "insert into user(name,age) values(?,?)";
getJdbcTemplate().update(sql,new Object[]{name,age});
}
public User find(Integer id) {
List rows = getJdbcTemplate().queryForList(
"SELECT * FROM user WHERE id=" + id.intValue());
Iterator it = rows.iterator();
if (it.hasNext()) {
Map userMap = (Map) it.next();
Integer i = new Integer(userMap.get("id").toString());
String name = userMap.get("name").toString();
Integer age = new Integer(userMap.get("age").toString());
User user = new User();
user.setId(i);
user.setName(name);
user.setAge(age);
return user;
}
return null;
}
}
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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING/DTD BEAN/EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id="dataSource"
class="org.apache.commons.dbcp.BasicDataSource" singleton="true">
<property name="driverClassName">
<value>com.mysql.jdbc.Driver</value>
</property>
<property name="url">
<value>jdbc:mysql://localhost:3306/springdb</value>
</property>
<property name="username">
<value>root</value>
</property>
<property name="password">
<value>leizhimin</value>
</property>
</bean>
<bean id="baseDAO" class="com.lavasoft.springnote.ch05_jdbc03_temp.BaseDAO" abstract="true">
<property name="dataSource">
<ref bean="dataSource"/>
</property>
</bean>
<bean id="userDAO"
class="com.lavasoft.springnote.ch05_jdbc03_temp.UserDAO" parent="baseDAO">
</bean>
</beans>
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import org.springframework.context.ApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;
/**
* Created by IntelliJ IDEA.<br>
* <b>User</b>: leizhimin<br>
* <b>Date</b>: 2008-4-22 15:59:18<br>
* <b>Note</b>: 测试类，客户端
*/
public class SpringDAODemo {
public static void main(String[] args) {
ApplicationContext context = new FileSystemXmlApplicationContext("D:\\_spring\\src\\com\\lavasoft\\springnote\\ch05_jdbc03_temp\\bean-jdbc-temp.xml");
User user = new User();
user.setName("hahhahah");
user.setAge(new Integer(22));
IUserDAO userDAO = (IUserDAO) context.getBean("userDAO");
userDAO.insert(user);
user = userDAO.find(new Integer(1));
System.out.println("name: " + user.getName());
}
}
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运行结果：
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log4j:WARN No appenders could be found for logger (org.springframework.core.CollectionFactory).
log4j:WARN Please initialize the log4j system properly.
name: jdbctemplate
Process finished with exit code 0
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Spring DAO之Hibernate
HibernateDaoSupport - Hibernate数据访问对象的基类。 需要一个SessionFactory，同时为子类提供 HibernateTemplate。也可以选择直接通过 提供一个HibernateTemplate来初始化， 这样就可以重用后者的设置，例如SessionFactory， flush模式，异常翻译器（exception translator）等等。
本节主要讨论Sping对HibernateTemplate的支持。
下面是个例子：
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drop table if exists user;
/*==============================================================*/
/* Table: user */
/*==============================================================*/
create table user
(
id bigint AUTO_INCREMENT not null,
name varchar(24),
age int,
primary key (id)
);
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/**
* Created by IntelliJ IDEA.<br>
* <b>Note</b>: Hiberante实体类
*/
public class User {
private Integer id;
private String name;
private Integer age;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
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<?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.lavasoft.springnote.ch06_hbm_02deTx.User"
table="user">
<id name="id" column="id">
<generator class="native"/>
</id>
<property name="name" column="name"/>
<property name="age" column="age"/>
</class>
</hibernate-mapping>
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/**
* Created by IntelliJ IDEA.<br>
* <b>User</b>: leizhimin<br>
* <b>Date</b>: 2008-4-23 15:37:43<br>
* <b>Note</b>: DAO接口
*/
public interface IUserDAO {
public void insert(User user);
public User find(Integer id);
}
import org.hibernate.SessionFactory;
import org.springframework.orm.hibernate3.HibernateTemplate;
/**
* Created by IntelliJ IDEA.<br>
* <b>User</b>: leizhimin<br>
* <b>Date</b>: 2008-4-23 15:15:55<br>
* <b>Note</b>: DAO实现
*/
public class UserDAO implements IUserDAO {
private HibernateTemplate hibernateTemplate;
public void setSessionFactory(SessionFactory sessionFactory) {
this.hibernateTemplate =new HibernateTemplate(sessionFactory);
}
public void insert(User user) {
hibernateTemplate.save(user);
System.out.println("所保存的User对象的ID:"+user.getId());
}
public User find(Integer id) {
User user =(User) hibernateTemplate.get(User.class, id);
return user;
}
}
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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING/DTD BEAN/EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName">
<value>com.mysql.jdbc.Driver</value>
</property>
<property name="url">
<value>jdbc:mysql://localhost:3306/springdb</value>
</property>
<property name="username">
<value>root</value>
</property>
<property name="password">
<value>leizhimin</value>
</property>
</bean>
<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"
destroy-method="close">
<property name="dataSource">
<ref bean="dataSource"/>
</property>
<property name="mappingResources">
<list>
<value>com/lavasoft/springnote/ch06_hbm_02proTx/User.hbm.xml</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">
org.hibernate.dialect.MySQLDialect
</prop>
</props>
</property>
</bean>
<bean id="userDAO" class="com.lavasoft.springnote.ch06_hbm_02proTx.UserDAO">
<property name="sessionFactory">
<ref bean="sessionFactory"/>
</property>
</bean>
</beans>
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import org.springframework.context.ApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;
/**
* Created by IntelliJ IDEA.<br>
* <b>Note</b>: 测试类、客户端
*/
public class SpringHibernateDemo {
public static void main(String[] args) {
ApplicationContext context =new FileSystemXmlApplicationContext("D:\\_spring\\src\\com\\lavasoft\\springnote\\ch06_hbm_02proTx\\bean-hbm_tx.xml");
// 建立DAO物件
IUserDAO userDAO = (IUserDAO) context.getBean("userDAO");
User user = new User();
user.setName("caterpillar");
user.setAge(new Integer(30));
userDAO.insert(user);
user = userDAO.find(new Integer(1));
System.out.println("name: " + user.getName());
}
}
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运行结果：
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log4j:WARN No appenders could be found for logger (org.springframework.core.CollectionFactory).
log4j:WARN Please initialize the log4j system properly.
所保存的User对象的ID:18
name: jdbctemplate
Process finished with exit code 0
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