DBCP连接池的最简单应用(用于ORACLE数据库)

鉴于有人问起DBCP直接用于JDBC连接的问题，我做了一个最简单的示例。所有资源来源于网上。它不需要什么Web容器，就是一简单的控制台应用。

资源：
http://apache.etoak.com//commons/pool/binaries/commons-pool-1.5.6-bin.zip
http://labs.renren.com/apache-mirror//commons/dbcp/binaries/commons-dbcp-1.4-bin.zip
http://download.java.net/maven/1/javaee/jars/javaee-api-5.jar
当然，还有oracle jdbc要用的ojdbc14.jar (适用于oracle9i及以上版本)

工程文件：放到这里了。 http://dl.iteye.com/topics/download/210279f0-f752-37a6-969f-d58ba13cc394

数据库连接信息：
jdbc:oracle:thin:scott/tiger@sean-m700:1521:ora92
sean-m700是主机名，ora92是oracle数据库的instance ID. 我手头的机器上没有安装oracle数据库，用的是很早以前的一个oracle9.2的拷贝，重新安装实例和相应服务得来的。

源码如下：借化献佛，源码也是从网上得来的。(http://svn.apache.org/viewvc/commons/proper/dbcp/trunk/doc/BasicDataSourceExample.java?revision=1100136&view=markup)

    /* 
    // 
    33  // Here's a simple example of how to use the BasicDataSource. 
    34  // 
    35   
    36  // 
    37  // Note that this example is very similiar to the PoolingDriver 
    38  // example. 
    39   
    40  // 
    41  // To compile this example, you'll want: 
    42  //  * commons-pool-1.5.6.jar 
    43  //  * commons-dbcp-1.3.jar (JDK 1.4-1.5) or commons-dbcp-1.4 (JDK 1.6+) 
    44  //  * j2ee.jar (for the javax.sql classes) 
    45  // in your classpath. 
    46  // 
    47  // To run this example, you'll want: 
    48  //  * commons-pool-1.5.6.jar 
    49  //  * commons-dbcp-1.3.jar (JDK 1.4-1.5) or commons-dbcp-1.4 (JDK 1.6+) 
    50  //  * j2ee.jar (for the javax.sql classes) 
    51  //  * the classes for your (underlying) JDBC driver 
    52  // in your classpath. 
    53  // 
    54  // Invoke the class using two arguments: 
    55  //  * the connect string for your underlying JDBC driver 
    56  //  * the query you'd like to execute 
    57  // You'll also want to ensure your underlying JDBC driver 
    58  // is registered.  You can use the "jdbc.drivers" 
    59  // property to do this. 
    60  // 
    61  // For example: 
    62  //  java -Djdbc.drivers=oracle.jdbc.driver.OracleDriver \ 
    63  //       -classpath commons-pool-1.5.6.jar:commons-dbcp-1.4.jar:j2ee.jar:oracle-jdbc.jar:. \ 
    64  //       PoolingDataSourceExample 
    65  //       "jdbc:oracle:thin:scott/tiger@myhost:1521:mysid" 
    66  //       "SELECT * FROM DUAL" 
    */  
    /* 
    The Oracle connection URL for the thin client-side driver ojdbc14.jar has the following format: 
    jdbc:oracle:thin:[user/password]@[host][:port]:SID 
    jdbc:oracle:thin:[user/password]@//[host][:port]/SID 
     
      user - The login user name defined in the Oracle server. 
     
      password - The password for the login user. 
     
      host - The host name where Oracle server is running.  
             Default is 127.0.0.1 - the IP address of localhost. 
     
      port - The port number where Oracle is listening for connection. 
             Default is 1521. 
     
      SID  - System ID of the Oracle server database instance.  
             SID is a required value. By default, Oracle Database 10g Express  
             Edition creates one database instance called XE. 
    */  
      
    import org.apache.commons.dbcp.BasicDataSource;  
    import javax.sql.*;  
    import java.sql.*;  
      
    public class TestDataSource  
    {  
      
        /** 
         * @param args 
         */  
        public static void main(String[] args)  
        {  
            System.out.println("Setting up data source.");  
            String url = "jdbc:oracle:thin:scott/tiger@sean-m700:1521:ora92";  
            DataSource dataSource = setupDataSource(url);  
            System.out.println("Done...");  
      
            // Now, we can use JDBC DataSource as we normally would.  
            //  
            Connection conn = null;  
            Statement stmt = null;  
            ResultSet rset = null;  
      
            try {  
                System.out.println("Creating connection.");  
                conn = dataSource.getConnection();  
                System.out.println("Creating statement.");  
                stmt = conn.createStatement();  
                System.out.println("Executing statement.");  
                rset = stmt.executeQuery("select 1 from DUAL");  
                System.out.println("Results:");  
                int numcols = rset.getMetaData().getColumnCount();  
                while(rset.next()) {  
                    for(int i=1;i<=numcols;i++) {  
                        System.out.print("\t" + rset.getString(i));  
                    }  
                    System.out.println("");  
                }  
            } catch(SQLException e) {  
                e.printStackTrace();  
            } finally {  
                try { if (rset != null) rset.close(); } catch(Exception e) { }  
                try { if (stmt != null) stmt.close(); } catch(Exception e) { }  
                try { if (conn != null) conn.close(); } catch(Exception e) { }  
            }  
        }  
      
        public static DataSource setupDataSource(String connectURI) {  
            BasicDataSource ds = new BasicDataSource();  
            ds.setDriverClassName("oracle.jdbc.driver.OracleDriver");  
            ds.setUsername("scott");  
            ds.setPassword("tiger");  
            ds.setUrl(connectURI);  
            return ds;  
        }  
      
        public static void printDataSourceStats(DataSource ds) {  
            BasicDataSource bds = (BasicDataSource) ds;  
            System.out.println("NumActive: " + bds.getNumActive());  
            System.out.println("NumIdle: " + bds.getNumIdle());  
        }  
      
        public static void shutdownDataSource(DataSource ds) throws SQLException {  
            BasicDataSource bds = (BasicDataSource) ds;  
            bds.close();  
        }  
      
    }  

不过，需要说明的是，DBCP连接池是几个开源连接池里最不适合用于生产环境的，经常会出现死连接现象。 而cp30和proxool都是不错的选择。DBCP用于测评开发环境，还是比较便利的。