Java的Spring框架中DAO數(shù)據(jù)訪問對象的使用示例

更新時間：2016年03月04日 08:53:18 作者：leizhimin

這篇文章主要介紹了Java的Spring框架中DAO數(shù)據(jù)訪問對象的使用示例,分為在Spring中DOA與JDBC以及與Hibernate的配合使用兩種情況來進行演示,需要的朋友可以參考下

Spring DAO之JDBC

Spring提供的DAO(數(shù)據(jù)訪問對象)支持主要的目的是便于以標準的方式使用不同的數(shù)據(jù)訪問技術(shù)，如JDBC，Hibernate或者JDO等。它不僅可以讓你方便地在這些持久化技術(shù)間切換，而且讓你在編碼的時候不用考慮處理各種技術(shù)中特定的異常。
為了便于以一種一致的方式使用各種數(shù)據(jù)訪問技術(shù)，如JDBC、JDO和Hibernate， Spring提供了一套抽象DAO類供你擴展。這些抽象類提供了一些方法，通過它們你可以獲得與你當前使用的數(shù)據(jù)訪問技術(shù)相關(guān)的數(shù)據(jù)源和其他配置信息。
Dao支持類：
JdbcDaoSupport - JDBC數(shù)據(jù)訪問對象的基類。需要一個DataSource，同時為子類提供 JdbcTemplate。
HibernateDaoSupport - Hibernate數(shù)據(jù)訪問對象的基類。需要一個SessionFactory，同時為子類提供 HibernateTemplate。也可以選擇直接通過提供一個HibernateTemplate來初始化，這樣就可以重用后者的設(shè)置，例如SessionFactory， flush模式，異常翻譯器（exception translator）等等。
JdoDaoSupport - JDO數(shù)據(jù)訪問對象的基類。需要設(shè)置一個PersistenceManagerFactory，同時為子類提供JdoTemplate。
JpaDaoSupport - JPA數(shù)據(jù)訪問對象的基類。需要一個EntityManagerFactory，同時為子類提供JpaTemplate。
本節(jié)主要討論Sping對JdbcDaoSupport的支持。
下面是個例子：

drop table if exists user; 

/*==============================================================*/ 
/* Table: user                         */ 
/*==============================================================*/ 
create table user 
( 
  id          bigint AUTO_INCREMENT not null, 
  name         varchar(24), 
  age         int, 
  primary key (id) 
);

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; 
  } 
}

/** 
* 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>: 基類DAO，提供了數(shù)據(jù)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實現(xiàn) 
*/ 
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; 
  } 
}

<?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>

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>: 測試類，客戶端 
*/ 
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()); 
  } 
}

運行結(jié)果：

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

Spring DAO之Hibernate

HibernateDaoSupport - Hibernate數(shù)據(jù)訪問對象的基類。需要一個SessionFactory，同時為子類提供 HibernateTemplate。也可以選擇直接通過提供一個HibernateTemplate來初始化，這樣就可以重用后者的設(shè)置，例如SessionFactory， flush模式，異常翻譯器（exception translator）等等。

本節(jié)主要討論Sping對HibernateTemplate的支持。

下面是個例子：

drop table if exists user; 

/*==============================================================*/ 
/* Table: user                         */ 
/*==============================================================*/ 
create table user 
( 
  id          bigint AUTO_INCREMENT not null, 
  name         varchar(24), 
  age         int, 
  primary key (id) 
);

/** 
* Created by IntelliJ IDEA.<br> 
* <b>Note</b>: Hiberante實體類 
*/ 
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; 
  } 
}

<?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>

/** 
* 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實現(xiàn) 
*/ 
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對象的ID:"+user.getId()); 
  } 

  public User find(Integer id) { 
    User user =(User) hibernateTemplate.get(User.class, id); 
    return user; 
  } 
}

<?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>

import org.springframework.context.ApplicationContext; 
import org.springframework.context.support.FileSystemXmlApplicationContext; 

/** 
* Created by IntelliJ IDEA.<br> 
* <b>Note</b>: 測試類、客戶端 
*/ 
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()); 
  } 
}

運行結(jié)果：

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對象的ID:18 
name: jdbctemplate 

Process finished with exit code 0

您可能感興趣的文章: