java并发(含volatile,单例,线程池,消息队列,事务)

BookCDRLog.java
 
/** 初始化锁 */
private static Object initLock = new Object();
 
synchronized (BookCDRLog.initLock)
            {
                if (!BookCDRLog.inited)
                {
                    instance.init();
                    BookCDRLog.inited = true;
                }
            }

同步锁：
ConnectionUtil.java
/** 实例锁 */
private static Lock lock = new ReentrantLock();
 
/** 连接锁[连接,释放] */
private static Lock connLock = new ReentrantLock();
 
    /**
     * 释放连接 <功能详细描述> [参数说明]
     *
     * @return void [返回类型说明]
     * @exception throws [违例类型] [违例说明]
     * @see [类、类#方法、类#成员]
     */
    public void release()
    {
        // 锁[getConnection(),release()]
        connLock.lock();
       
        try
        {
            if (null != conn && !conn.isClosed())
            {
                conn.close();
            }
        }
        catch (SQLException e)
        {
            logger.error("关闭连接错误!" + e.getMessage());
        }
        finally
        {
            // 锁-释放[getConnection(),release()]
            connLock.unlock();
        }
    }

/**   
 * 实现单例访问Kerrigan的第五次尝试   
 */    
public class SingletonKerriganE {     
      
    /**   
     * 单例对象实例   
     */    
    private static SingletonKerriganE instance = new SingletonKerriganE();     
      
    public static SingletonKerriganE getInstance() {     
        return instance;     
    }     
}

/**   
 * 实现单例访问Kerrigan的第一次尝试   
 */    
public class SingletonKerriganA {     
      
    /**   
     * 单例对象实例   
     */    
    private static SingletonKerriganA instance = null;     
      
    public static SingletonKerriganA getInstance() {     
        if (instance == null) {                              //line A     
            instance = new SingletonKerriganA();          //line B     
        }     
        return instance;     
    }     
}

/**   
 * 实现单例访问Kerrigan的第四次尝试   
 */    
public class SingletonKerriganD {     
      
    /**   
     * 单例对象实例   
     */    
    private static SingletonKerriganD instance = null;     
      
    public static SingletonKerriganD getInstance() {     
        if (instance == null) {     
            synchronized (SingletonKerriganD.class) {     
                if (instance == null) {     
                    instance = new SingletonKerriganD();     
                }     
            }     
        }     
        return instance;     
    }     
}

/**   
 * 实现单例访问Kerrigan的第六次尝试   
 */    
public class SingletonKerriganF {     
      
    private static class SingletonHolder {     
        /**   
         * 单例对象实例   
         */    
        static final SingletonKerriganF INSTANCE = new SingletonKerriganF();     
    }     
      
    public static SingletonKerriganF getInstance() {     
        return SingletonHolder.INSTANCE;     
    }     
}

/**   
 * 实现单例访问Kerrigan的第四次尝试   
 */    
public class SingletonKerriganD {     
      
    /**   
     * 单例对象实例   
     */    
    private static SingletonKerriganD instance = null;     
      
    public static SingletonKerriganD getInstance() {     
        if (instance == null) {     
            synchronized (SingletonKerriganD.class) {     
                if (instance == null) {     
                    instance = new SingletonKerriganD();     
                }     
            }     
        }     
        return instance;     
    }     
}