工具类4

package cn.itcast.jdbc;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

import javax.sql.DataSource;

import org.apache.commons.dbcp.BasicDataSourceFactory;

public final class JdbcUtils {

private static DataSource myDataSource = null;

private JdbcUtils() {
}

static {
try {
Properties prop = new Properties();
InputStream is = JdbcUtils.class.getClassLoader()
.getResourceAsStream("dbcpconfig.properties");
prop.load(is);
myDataSource = BasicDataSourceFactory.createDataSource(prop); // 屏蔽了创建数据源的过程
} catch (Exception e) {
throw new ExceptionInInitializerError(e);
}
}

public static Connection getConnection() throws SQLException {
// return DriverManager.getConnection(url, user, password);
return myDataSource.getConnection(); // 取连接
}

public static void free(ResultSet rs, Statement st, Connection conn) {
try {
if (rs != null)
rs.close();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
if (st != null)
st.close();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
if (conn != null)
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}