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疑惑DBCP的两种使用方法！

摘要: 疑惑DBCP的两种使用方法！

初学JSP/SERVLET，数据库部分想使用DBCP，从其主页上下到了几个小例子，其中似乎有两种使用方法，有点不解其区别，请高手指教这两种使用方法有什么异同。

ManualPoolingDataSourceExample.java

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;


import org.apache.commons.pool.ObjectPool;
import org.apache.commons.pool.impl.GenericObjectPool;
import org.apache.commons.dbcp.ConnectionFactory;
import org.apache.commons.dbcp.PoolingDataSource;
import org.apache.commons.dbcp.PoolableConnectionFactory;
import org.apache.commons.dbcp.DriverManagerConnectionFactory;

// java -Djdbc.drivers=oracle.jdbc.driver.OracleDriver /
// -classpath commons-collections.jar:commons-pool.jar:commons-dbcp.jar:j2ee.jar:oracle-jdbc.jar:. /
// ManualPoolingDataSourceExample
// "jdbc:oracle:thin:scott/tiger@myhost:1521:mysid"
// "SELECT * FROM DUAL"
//
public class ManualPoolingDataSourceExample {

public static void main(String[] args) {
//
// First we load the underlying JDBC driver.
// You need this if you don't use the jdbc.drivers
// system property.
//
System.out.println("Loading underlying JDBC driver.");
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
System.out.println("Done.");

//
// Then, we set up the PoolingDataSource.
// Normally this would be handled auto-magically by
// an external configuration, but in this example we'll
// do it manually.
//
System.out.println("Setting up data source.");
DataSource dataSource = setupDataSource(args[0]);
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(args[1]);
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 { rset.close(); } catch(Exception e) { }
try { stmt.close(); } catch(Exception e) { }
try { conn.close(); } catch(Exception e) { }
}
}

public static DataSource setupDataSource(String connectURI) {
ObjectPool connectionPool = new GenericObjectPool(null);

ConnectionFactory connectionFactory = new DriverManagerConnectionFactory(connectURI,null);

PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory(connectionFactory,connectionPool,null,null,false,true);

PoolingDataSource dataSource = new PoolingDataSource(connectionPool);

return dataSource;
}
}




ManualPoolingDriverExample.java

import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;

import org.apache.commons.pool.ObjectPool;
import org.apache.commons.pool.impl.GenericObjectPool;
import org.apache.commons.dbcp.ConnectionFactory;
import org.apache.commons.dbcp.PoolingDriver;
import org.apache.commons.dbcp.PoolableConnectionFactory;
import org.apache.commons.dbcp.DriverManagerConnectionFactory;

public class ManualPoolingDriverExample {

public static void main(String[] args) {
System.out.println("Loading underlying JDBC driver.");
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
System.out.println("Done.");
System.out.println("Setting up driver.");
try {
setupDriver(args[0]);
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("Done.");

Connection conn = null;
Statement stmt = null;
ResultSet rset = null;

try {
System.out.println("Creating connection.");
conn = DriverManager.getConnection("jdbc:apache:commons:dbcp:example");
System.out.println("Creating statement.");
stmt = conn.createStatement();
System.out.println("Executing statement.");
rset = stmt.executeQuery(args[1]);
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 { rset.close(); } catch(Exception e) { }
try { stmt.close(); } catch(Exception e) { }
try { conn.close(); } catch(Exception e) { }
}

// Display some pool statistics
try {
printDriverStats();
} catch (Exception e) {
e.printStackTrace();
}

// closes the pool
try {
shutdownDriver();
} catch (Exception e) {
e.printStackTrace();
}
}

public static void setupDriver(String connectURI) throws Exception {

ObjectPool connectionPool = new GenericObjectPool(null);
ConnectionFactory connectionFactory = new DriverManagerConnectionFactory(connectURI,null);
PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory(connectionFactory,connectionPool,null,null,false,true);

Class.forName("org.apache.commons.dbcp.PoolingDriver");
PoolingDriver driver = (PoolingDriver) DriverManager.getDriver("jdbc:apache:commons:dbcp:");

//
// ...and register our pool with it.
//
driver.registerPool("example",connectionPool);

}

public static void printDriverStats() throws Exception {
PoolingDriver driver = (PoolingDriver) DriverManager.getDriver("jdbc:apache:commons:dbcp:");
ObjectPool connectionPool = driver.getConnectionPool("example");

System.out.println("NumActive: " + connectionPool.getNumActive());
System.out.println("NumIdle: " + connectionPool.getNumIdle());
}

public static void shutdownDriver() throws Exception {
PoolingDriver driver = (PoolingDriver) DriverManager.getDriver("jdbc:apache:commons:dbcp:");
driver.closePool("example");
}
}

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第一个 返回的是DataSource
第二个 是设置驱动
好像

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