Spring 事務管理高階應用難點剖析: 第 2 部分

				
import javax.persistence.Entity; 
import javax.persistence.Table; 
import javax.persistence.Column; 
import javax.persistence.Id; 
import java.io.Serializable; 

@Entity 
@Table(name="T_USER") 
public class User implements Serializable{ 
    @Id
    @Column(name = "USER_NAME") 
    private String userName; 
    private String password; 
    private int score; 
    
	@Column(name = "LAST_LOGON_TIME")
    private long lastLogonTime = 0;  
}

				
package user.mixdao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Service;
import org.springframework.orm.hibernate3.HibernateTemplate;
import org.apache.commons.dbcp.BasicDataSource;
import user.User;

@Service("userService")
public class UserService extends BaseService {
    @Autowired
    private HibernateTemplate hibernateTemplate;

    @Autowired
    private ScoreService scoreService;

    public void logon(String userName) {
        System.out.println("logon method...");
        updateLastLogonTime(userName); //①使用Hibernate資料訪問技術
        scoreService.addScore(userName, 20); //②使用Spring JDBC資料訪問技術
    }

    public void updateLastLogonTime(String userName) {
        System.out.println("updateLastLogonTime...");
        User user = hibernateTemplate.get(User.class,userName);
        user.setLastLogonTime(System.currentTimeMillis());
        hibernateTemplate.flush(); //③請看下文的分析
    }
}

				
package user.mixdao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Service;
import org.apache.commons.dbcp.BasicDataSource;

@Service("scoreUserService")
public class ScoreService extends BaseService{
    @Autowired
    private JdbcTemplate jdbcTemplate;
    public void addScore(String userName, int toAdd) {
        System.out.println("addScore...");
        String sql = "UPDATE t_user u SET u.score = u.score + ? WHERE user_name =?";
        jdbcTemplate.update(sql, toAdd, userName);
        //① 檢視此處資料庫啟用的連線數
        BasicDataSource basicDataSource = (BasicDataSource) jdbcTemplate.getDataSource();
        System.out.println("啟用連線數量："+basicDataSource.getNumActive());
    }
}

				
<!-- 使用Hibernate事務管理器 -->
<bean id="hiberManager"
    class="org.springframework.orm.hibernate3.HibernateTransactionManager"
    p:sessionFactory-ref="sessionFactory"/>
    
<!-- 對所有繼承BaseService類的公用方法實施事務增強 -->
<aop:config proxy-target-class="true">
    <aop:pointcut id="serviceJdbcMethod"
        expression="within(user.mixdao.BaseService+)"/>
    <aop:advisor pointcut-ref="serviceJdbcMethod"
        advice-ref="hiberAdvice"/>
</aop:config>
    
<tx:advice id="hiberAdvice" transaction-manager="hiberManager">
    <tx:attributes>
        <tx:method name="*"/>
    </tx:attributes>
</tx:advice>

				
12:38:57,062  (AbstractPlatformTransactionManager.java:365) - Creating new transaction 
    with name [user.mixdao.UserService.logon]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT

12:38:57,093  (SessionImpl.java:220) - opened session at timestamp: 12666407370

12:38:57,093  (HibernateTransactionManager.java:493) - Opened new Session 
    [org.hibernate.impl.SessionImpl@83020] for Hibernate transaction ①

12:38:57,093  (HibernateTransactionManager.java:504) - Preparing JDBC Connection 
    of Hibernate Session [org.hibernate.impl.SessionImpl@83020]

12:38:57,109  (JDBCTransaction.java:54) - begin

…

logon method...
updateLastLogonTime...
…

12:38:57,109  (AbstractBatcher.java:401) - select user0_.USER_NAME as USER1_0_0_, 
    user0_.LAST_LOGON_TIME as LAST2_0_0_, user0_.password as password0_0_, 
	user0_.score as score0_0_ from T_USER user0_ where user0_.USER_NAME=?
    
Hibernate: select user0_.USER_NAME as USER1_0_0_, 
	user0_.LAST_LOGON_TIME as LAST2_0_0_, user0_.password as password0_0_, 
	user0_.score as score0_0_ from T_USER user0_ where user0_.USER_NAME=?

…

12:38:57,187  (HibernateTemplate.java:422) - Not closing pre-bound 
    Hibernate Session after HibernateTemplate

12:38:57,187  (HibernateTemplate.java:397) - Found thread-bound Session
    for HibernateTemplate

Hibernate: update T_USER set LAST_LOGON_TIME=?, password=?, score=? where USER_NAME=?

…

2010-02-20 12:38:57,203 DEBUG [main] (AbstractPlatformTransactionManager.java:470) 
    - Participating in existing transaction ②
addScore...

2010-02-20 12:38:57,203 DEBUG [main] (JdbcTemplate.java:785) 
    - Executing prepared SQL update

2010-02-20 12:38:57,203 DEBUG [main] (JdbcTemplate.java:569)
    - Executing prepared SQL statement 
	[UPDATE t_user u SET u.score = u.score + ? WHERE user_name =?]

2010-02-20 12:38:57,203 DEBUG [main] (JdbcTemplate.java:794) 
    - SQL update affected 1 rows

啟用連線數量：1 ③
2010-02-20 12:38:57,203 DEBUG [main] (AbstractPlatformTransactionManager.java:752) 
    - Initiating transaction commit
2010-02-20 12:38:57,203 DEBUG [main] (HibernateTransactionManager.java:652) 
    - Committing Hibernate transaction on Session 
	[org.hibernate.impl.SessionImpl@83020] ④

2010-02-20 12:38:57,203 DEBUG [main] (JDBCTransaction.java:103) - commit ⑤
			

				
package user.special;
import org.springframework.stereotype.Service;

@Service("userService")
public class UserService {
    
	//① private方法因訪問許可權的限制，無法被子類覆蓋
    private void method1() {
        System.out.println("method1");
    }
    
	//② final方法無法被子類覆蓋
    public final void method2() {
        System.out.println("method2");
    }

    //③ static是類級別的方法，無法被子類覆蓋
    public static void method3() {
        System.out.println("method3");
    }
    
	//④ public方法可以被子類覆蓋，因此可以被動態位元組碼增強
    public void method4() {
        System.out.println("method4");
    } 
}

				
<?xml version="1.0" encoding="UTF-8" ?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:p="http://www.springframework.org/schema/p" 
	xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
	    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context 
	    http://www.springframework.org/schema/context/spring-context-3.0.xsd 
		http://www.springframework.org/schema/aop 
		http://www.springframework.org/schema/aop/spring-aop-3.0.xsd 
		http://www.springframework.org/schema/tx 
		http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

    <!-- 省略宣告資料來源及DataSourceTransactionManager事務管理器-->
    …
    <aop:config proxy-target-class="true">
	    <!-- ①顯式使用CGLib動態代理 -->
        <!-- ②希望對UserService所有方法實施事務增強 -->
        <aop:pointcut id="serviceJdbcMethod"
            expression="execution(* user.special.UserService.*(..))"/>
        <aop:advisor pointcut-ref="serviceJdbcMethod" 
            advice-ref="jdbcAdvice" order="0"/>
    </aop:config>
    <tx:advice id="jdbcAdvice" transaction-manager="jdbcManager">
        <tx:attributes>
            <tx:method name="*"/>
        </tx:attributes>
    </tx:advice>
</beans>

				
package user.special;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Service;

@Service("userService")
public class UserService {
    …
    public static void main(String[] args) {
        ApplicationContext ctx = 
            new ClassPathXmlApplicationContext("user/special/applicationContext.xml");
        
		UserService service = (UserService) ctx.getBean("userService");

        System.out.println("before method1");
        service.method1();
        System.out.println("after method1");

        System.out.println("before method2");
        service.method2();
        System.out.println("after method2");

        System.out.println("before method3");
        service.method3();
        System.out.println("after method3");

        System.out.println("before method4");
        service.method4();
        System.out.println("after method4");

    }
}

17:24:10,953  (AbstractBeanFactory.java:241) 
    - Returning cached instance of singleton bean 'userService'

before method1
method1
after method1
before method2
method2
after method2
before method3
method3
after method3
before method4

17:24:10,953  (AbstractPlatformTransactionManager.java:365) 
    - Creating new transaction with name [user.special.UserService.method4]: 
	PROPAGATION_REQUIRED,ISOLATION_DEFAULT

17:24:11,109  (DataSourceTransactionManager.java:205) 
    - Acquired Connection [org.apache.commons.dbcp.PoolableConnection@165b7e] 
	for JDBC transaction

…

17:24:11,109  (DataSourceTransactionManager.java:265) 
    - Committing JDBC transaction on Connection 
	[org.apache.commons.dbcp.PoolableConnection@165b7e]

17:24:11,125  (DataSourceTransactionManager.java:323) 
    - Releasing JDBC Connection [org.apache.commons.dbcp.PoolableConnection@165b7e] 
	after transaction

17:24:11,125  (DataSourceUtils.java:312) 
    - Returning JDBC Connection to DataSource

after method4