java连接数据库

java通过jdbc连接oracle和mysql 

相关链接：

OJDBC所有版本下载：https://download.youkuaiyun.com/download/qq_31049375/10688712

OJDBC版本说明：https://blog.youkuaiyun.com/qq_31049375/article/details/82853074

MySql_JDBC下载：https://download.youkuaiyun.com/download/qq_31049375/10688798

package com.yhh.dao;

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

public class BaseDao {
	/*
	 * OJDBC的URL有两种常用格式
	 * 
	 * 1.通过SID连接ORACLE
	 * SID查询方式：  select value from v$parameter where name=’instance_name’
	 * url="jdbc:oracle:thin:@host:port:SID";
	 * port默认是1521
	 *
	 * 2.通过数据库名连接ORACLE
	 * 数据库名查询方式：select value from v$parameter where name=’service_names’
	 * url="jdbc:oracle:thin:@//host:port/service_name";
	 * port默认是1521
	 * 
	 * MySql的URL格式
	 * url="jdbc:mysql://host:port/db_name";
	 * port 默认是 3306
	 */
	private static String url="url";
	/*
	 * oracle的驱动器
	 * String jdbc_driver="oracle.jdbc.driver.OracleDriver"
	 * 
	 * mysql的驱动器
	 * String jdbc_driver="com.mysql.jdbc.Driver";
	 */
	private static String jdbc_driver="driver";
	private static String username="username";
	private static String password="password";
	
	public static Connection conn=null;
	public static Statement stmt=null;
	public static ResultSet rs=null;
	
	public static Connection openConnection() {
		try {
			Class.forName(jdbc_driver);
			conn = DriverManager.getConnection(url, username, password);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return conn;
	}
	
	public static void closeConnection() {
		if (conn != null) {
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
		if (stmt != null) {
			try {
				stmt.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
		if (rs != null) {
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
}