java--jdbc连接数据库

db.properties内容：
driver=oracle.jdbc.driver.OracleDriver
url=jdbc:oracle:thin:@$IP地址$:1521:tns数据库名
user=账号
pwd=密码
initsize=1
maxsize=10

代码如下：
import org.apache.commons.dbcp.BasicDataSource;
import java.io.IOException;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

/**
 * Created by zhangzubin on 2017/11/17.
 */
public class DBUtil {
    private static BasicDataSource ds;

    static {
        Properties p = new Properties();
        try {
            //加载配置文件
            p.load(DBUtil.class.getClassLoader()
                    .getResourceAsStream("db.properties"));
            String driver = p.getProperty("driver");
            String url = p.getProperty("url");
            String user = p.getProperty("user");
            String pwd = p.getProperty("pwd");
            String initsize = p.getProperty("initsize");
            String maxsize = p.getProperty("maxsize");
            //创建连接池
            ds = new BasicDataSource();
            //注册驱动
            ds.setDriverClassName(driver);
            ds.setUrl(url);
            ds.setUsername(user);
            ds.setPassword(pwd);
            ds.setInitialSize(new Integer(initsize));
            ds.setMaxActive(new Integer(maxsize));
        } catch (IOException e) {
            e.printStackTrace();
            throw new RuntimeException(
                    "初始化连接池失败！", e);
        }
    }

    /**
     * 通过连接池获取连接
     */
    public static Connection getConnection()
            throws SQLException {
        return ds.getConnection();
    }

    /**
     * 关闭连接
     * */
    public static void close(Connection conn) {
        if(conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
                throw new RuntimeException(
                        "关闭连接失败！", e);
            }
        }
    }
}