JDBC 连接池

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Vector;

public class DBConnectionPool {

public static final Vector pool = new Vector();
private static final int MAX_SIZE = 10;
private static final int MIN_SIZE = 3;
static {
for (int i = 0; i < MIN_SIZE; i++) {
Connection conn = createConnection();
pool.add(conn);
}
}

public static Connection createConnection() {
Connection conn = null;
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection("jdbc:mysql://10.100.3.192/people", "root", "");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}

/**
* 从连接池里面取得到connection，如果池里面没有connection，创建connection返回
* 如果池里存在connection，直接从pool取一个connection返回
*
* @return
*/
public static synchronized Connection getConnection() {
Connection conn = null;

if (pool.isEmpty()) {
conn = createConnection();
} else {
int last_idx = pool.size() - 1;
conn = (Connection) pool.get(last_idx);
pool.remove(conn);
}
return conn;
}


public static void main(String[] args) {
Connection conn = getConnection();
System.out.println(conn);
}

/**
*
* 释放connection，如果当前池连接的数量不超过10个，放回，如果超过10，直接关闭，不会放回池
*
* @param conn
*/

public static synchronized void releaseConnection(Connection conn) {

if (pool.size() < MAX_SIZE) {
pool.add(conn);
} else {
try {
if (conn != null)
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

public static void close(ResultSet rs) {
try {
if (rs != null)
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

public static void close(PreparedStatement pstmt) {
try {
if (pstmt != null)
pstmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

}