关于数据库连接池的一个代码

soft1999 2006-03-07 11:41:29

因为小弟对JNDI以及配置容器不熟悉.所以直接找了个池代码.

public class ConnectionPool {

//连接池的管理器,首先初始化，仅仅有一个对象，管理连接池
private static HashMap connectionPoolManager = new HashMap();
//没有用过的连接池，用vector实现同步
private static Vector noUseConnectionPool= new Vector();
//没有用过的连接池
private static HashMap nowUseConnectionPool = new HashMap();

private static String dbDriver = "oracle.jdbc.driver.OracleDriver";
private static String dbUrl = "jdbc:oracle:thin:@localhost:1521:db";
private static String userName = "yourname";
private static String userPassword = "yourpassword";

//默认为100个连接池
private static int MAX_POOL = 100;

//singleTon 设计模式
private ConnectionPool(String driver, String url, String name,
String password, int max) throws
ClassNotFoundException {
Class.forName(driver);
dbUrl = url;
userName = name;
userPassword = password;
MAX_POOL = max;
}

public static ConnectionPool getConnManagerInstance(String poolName) throws
ClassNotFoundException {
ConnectionPool tempPool = (ConnectionPool) connectionPoolManager.get(
poolName);
if (tempPool == null) {
tempPool = new ConnectionPool(dbDriver, dbUrl, userName, userPassword,
MAX_POOL);
connectionPoolManager.put(poolName, tempPool);
return tempPool;
}
else {
return tempPool;
}
}

//通过连接池获得真正的链接
public static Connection getConnection() throws java.sql.SQLException {
Connection conn = null;
synchronized (noUseConnectionPool) {
if (noUseConnectionPool.size() > 0) {
conn = (Connection) noUseConnectionPool.firstElement();
noUseConnectionPool.remove(conn);
return conn;
}
}
//如果数据库连接池没有链接了，自己创建一个
if (conn == null) {
conn = createConnection(dbDriver, dbUrl, userName, userPassword);
}
else if (conn.isClosed()) {
nowUseConnectionPool.remove(conn);
conn = createConnection(dbDriver, dbUrl, userName, userPassword);
}
conn.setAutoCommit(false);
nowUseConnectionPool.put(conn, conn);
return conn;
}

//如果连接池没有链接了，就需要产生一个链接
private static Connection createConnection(String driver, String url,
String user, String password) throws
java.sql.SQLException {
Connection conn = DriverManager.getConnection(url, user, password);
return conn;
}

public static void releaseConnection(Connection conn, boolean isCommit) throws
java.sql.SQLException {
if (isCommit) {
conn.commit();
}
else {
conn.rollback();
}
nowUseConnectionPool.remove(conn);
if (noUseConnectionPool.size() + nowUseConnectionPool.size() < MAX_POOL) {
synchronized (noUseConnectionPool) {
noUseConnectionPool.add(conn);
}
}
else {
conn.close();
}
}
}

这是我从网上找的一段cp的代码.自己研究了下,有些地方不大明白.因为用到SINGLETON模式.所以我觉得取得Connection应该是
Connection conn=getConnManagerInstance(String poolName).getConnection();//但是这里的poolName怎么用啊??还有就是createConnection和releaseConnection什么时候用?高手方便时候能写个例子看下么??

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