五种数据库连接
说明: 本文通过maven构建,连接的数据库是mysql 数据库
pom.xml
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
</dependency>
数据库连接方式一
public static void Connection1() throws SQLException {
/**
* @Description: 获取数据库连接的方式一
* @Author: Mr.Tony
* @Date: 2020/7/11 9:35
* @Param: []
* @Return: void
*/
Driver drive=new com.mysql.jdbc.Driver();
String url="jdbc:mysql://localhost:3306/test";
Properties info=new Properties();
info.setProperty("user","root");
info.setProperty("password","root");
Connection connect = drive.connect(url, info);
System.out.println(connect);
}
数据库连接方式二
public static void Connection2() throws ClassNotFoundException, InstantiationException, IllegalAccessException, SQLException {
// 1.获取Driver实现类对象:使用反射
Class clazz = Class.forName("com.mysql.jdbc.Driver");
Driver driver = (Driver) clazz.newInstance();
// 2.提供要连接的数据库
String url = "jdbc:mysql://localhost:3306/test";
// 3.提供连接需要的用户名和密码
Properties info = new Properties();
info.setProperty("user", "root");
info.setProperty("password", "root");
// 4.获取连接
Connection conn = driver.connect(url, info);
System.out.println(conn);
}
数据库连接方式三
// 1.获取Driver实现类的对象
Class clazz = Class.forName("com.mysql.jdbc.Driver");
Driver driver = (Driver) clazz.newInstance();
// 2.提供另外三个连接的基本信息:
String url = "jdbc:mysql://localhost:3306/test";
String user = "root";
String password = "root";
// 注册驱动
DriverManager.registerDriver(driver);
// 获取连接
Connection conn = DriverManager.getConnection(url, user, password);
System.out.println(conn);
数据库连接方式四
String url = "jdbc:mysql://localhost:3306/test";
String user = "root";
String password = "root";
// 2.加载Driver
Class.forName("com.mysql.jdbc.Driver");
// 3.获取连接
Connection conn = DriverManager.getConnection(url, user, password);
System.out.println(conn);
数据库连接方式五 非常推荐使用(通过配置文件)
好处 :
- 1.实现了数据与代码的分离。实现了解耦
- 2.如果需要修改配置文件信息,可以避免程序重新打包。
配置信息:
jdbc.properties
user=root
password=root
url=jdbc:mysql://localhost:3306/test?rewriteBatchedStatements=true
driverClass=com.mysql.jdbc.Driver
Java文件:
InputStream is = connDate.class.getClassLoader().getResourceAsStream("jdbc.properties");
Properties pros = new Properties();
pros.load(is);
String user = pros.getProperty("user");
String password = pros.getProperty("password");
String url = pros.getProperty("url");
String driverClass = pros.getProperty("driverClass");
//2.加载驱动
Class.forName(driverClass);
//3.获取连接
Connection conn = DriverManager.getConnection(url, user, password);
System.out.println(conn);