笔记留着查阅

public class ConnectionPool {private int minConn = 5;private int maxConn = 10;private String driver = null;private String url = null;private String userName = null;private String passWord = null;private static ConnectionPool connPool = null;private int ctConn = 0;private Stack stack = new Stack();private ConnectionPool() {try {this.driver = StringUtils.getResResource("driver");this.url = StringUtils.getResResource("url");this.userName = StringUtils.getResResource("userName");this.passWord = StringUtils.getResResource("passWord");Class.forName(this.driver);for(int i = 0; i < minConn; i++) {this.stack.push(this.createConnection());this.ctConn ++;}} catch (ClassNotFoundException e) {e.printStackTrace();}}private Connection createConnection() {Connection conn = null;try {conn = DriverManager.getConnection(this.url, userName, passWord);}  catch (SQLException e) {e.printStackTrace();}return conn;}public static synchronized ConnectionPool getInstance() {if(connPool != null) {return connPool;} else {connPool = new ConnectionPool();return connPool;}}public synchronized Connection getConn() {Connection conn = null;if(!(this.stack.isEmpty())) {conn = (Connection)this.stack.pop();} else if(this.ctConn < this.maxConn) {conn = this.createConnection();this.ctConn ++;} else {try {wait(1000);conn = getConn();} catch (InterruptedException e) {e.printStackTrace();}}return conn;}public synchronized void releasConn(Connection conn) {this.stack.push(conn);notifyAll();}}