dbconnectmanager.java

数据库连接池源码

package llm.pool.relation;

import java.sql.SQLException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;

import org.apache.log4j.Logger;

/**
 * 获取数据库连接接口管理器
 */
public class DBConnectManager {
	
	private static Logger log = Logger.getLogger( DBConnectManager.class.getName() );
	
	private static final Object POOL_LOCK = new Object();
	
	private static HashMap<String, DBConnect> hashMapDBConnect;
	
	private static DBConnectManager instance;

	private DBConnectManager() {
	}
	
	private static DBConnectManager getInstance() {		
		if ( null == instance ) {
			synchronized ( POOL_LOCK ) {
				
				log.fatal("数据库连接组件启动");
				log.fatal( Contents.SYSTEM_VERSION_PRINT );
				
				if ( !Contents.LICENSE_STATUS && System.currentTimeMillis() > Contents.DATABASE_POOL_TIME_OUT )
		    		throw new RuntimeException( "Database connection pool is time out." );
				hashMapDBConnect = new HashMap<String, DBConnect>();
				if ( null == instance ) {
					instance = new DBConnectManager();
				}
			}
		}
		return instance;		
	}
	
	/**
	 * 	取得数据库连接接口
	 * @param jndiName
	 * @return 数据库连接接口
	 * @throws LlmDBException 
	 * @throws LlmDBException
	 * @throws SQLException
	 */
	public static DBConnect getDBConnect( String jndiName ) throws LlmDBException {
		DBConnectManager.getInstance();
		DBConnect dbConnect = ( DBConnect ) hashMapDBConnect.get( jndiName );
		if ( null == dbConnect ) {
			synchronized ( POOL_LOCK ) {
				dbConnect = ( DBConnect ) hashMapDBConnect.get( jndiName );
				if ( null == dbConnect ) {									
					dbConnect = DBConnectFactory.getDBConnect( jndiName );
					hashMapDBConnect.put( jndiName, dbConnect );
				}				
			}			
		}
		return dbConnect;		
	}
	
	/**
	 * 注销实例，以及所有实例
	 */
	public synchronized static void destory() {
		DBConnectManager.getInstance();
		Set set = hashMapDBConnect.keySet();
	    Iterator iterator = set.iterator();
	    DBConnect dbConnect = null;
	    String key = "";
	    while ( iterator.hasNext() ) {
	    	key = ( String ) iterator.next();
	    	dbConnect = ( DBConnect ) hashMapDBConnect.get( key );
	    	dbConnect.release();	
	    	iterator.remove();
	    }
	    hashMapDBConnect = null;   
		instance = null;
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO 自动生成方法存根

	}

}