What are the ways to connect JDBC to Mysql?

Test environment description

mysql database: jdbc:mysql://localhost:3306/test

IDE: IDEA 2022

JDK: JDK8

mysql：mysql 5.7

JDBC：5.1.37

The first way

Use static loading driver method to connect mysql

This method is flexible Poor performance and strong dependence

public void connection01() throws SQLException {
    // 注册驱动
    Driver driver = new Driver();
    // 创建Properties对象，用于保存mysql账号和密码键值对
    Properties properties = new Properties();
    properties.setProperty("user", "root");
    properties.setProperty("password", "123456");
    String url = "jdbc:mysql://localhost:3306/test";
    // 得到mysql的连接
    Connection connection = driver.connect(url, properties);
    // 得到可以与mysql语句进行交互的对象
    Statement statement = connection.createStatement();
    // 关闭与 mysql语句进行交互的对象
    statement.close();
    // 关闭与mysql的连接
    connection.close();

The second method

uses reflection to dynamically load the driver based on the first method, reducing dependence and improving flexibility

public void connection02() throws ClassNotFoundException, InstantiationException, IllegalAccessException, SQLException {
    // 使用反射动态加载mysql驱动件程序
    Class<?> aClass = Class.forName("com.mysql.jdbc.Driver");
    Driver driver = (Driver) aClass.newInstance();
    // 创建Properties对象，用于保存mysql账号和密码键值对
    Properties properties = new Properties();
    properties.setProperty("user", "root");
    properties.setProperty("password", "123456");
    String url = "jdbc:mysql://localhost:3306/test";
    // 得到mysql的连接
    Connection connection = driver.connect(url, properties);
    // 得到可以与mysql语句进行交互的对象
    Statement statement = connection.createStatement();
    // 关闭与 mysql语句进行交互的对象
    statement.close();
    // 关闭与 mysql语句进行交互的对象
    connection.close();
}

The third way

Use DriverManager for unified management

public void connection03() throws ClassNotFoundException, InstantiationException, IllegalAccessException, SQLException {
	// 使用反射动态加载mysql驱动件程序
    Class<?> aClass = Class.forName("com.mysql.jdbc.Driver");
    Driver driver = (Driver) aClass.newInstance();
    String user = "root";
    String password = "123456";
    String url = "jdbc:mysql://localhost:3306/test";
    // 使用DriverManager加载Driver
    DriverManager.registerDriver(driver);
    // 得到mysql的连接
    Connection connection = DriverManager.getConnection(url, user, password);
    // 得到可以与mysql语句进行交互的对象
    Statement statement = connection.createStatement();
    // 关闭与 mysql语句进行交互的对象
    statement.close();
    // 关闭与 mysql语句进行交互的对象
    connection.close();
}

The fourth way

In fact, Class.forName("com.mysql.jdbc.Driver") is at the bottom The Driver instance has been loaded automatically

So Driver driver = (Driver) aClass.newInstance(); this sentence can be omitted

This method is also the most used in development One way

public void connection04() throws ClassNotFoundException, SQLException {
    // 使用反射动态加载mysql驱动件程序
    Class<?> aClass = Class.forName("com.mysql.jdbc.Driver");
    String user = "root";
    String password = "123456";
    String url = "jdbc:mysql://localhost:3306/test";
    // 得到mysql的连接
    Connection connection = DriverManager.getConnection(url, user, password);
    // 得到可以与mysql语句进行交互的对象
    Statement statement = connection.createStatement();
    // 关闭与 mysql语句进行交互的对象
    statement.close();
    // 关闭与 mysql语句进行交互的对象
    connection.close();
}

The fifth way

After mysql5.16, you can no longer load the driver with Class.forName(“com.mysql.jdbc.Driver”);
Since jdbc4 has been used since jdk1.5, it is no longer necessary to explicitly call class.forName() to register the driver, but to automatically call the class name in the META-INF\services\java.sql.Driver text under the driver jar package to register
It is recommended to write CLass. forName("com.mysql.jdbc.Driver"), which is more clear and has better compatibility

The properties configuration file is also used here to dynamically read dynamic information. , the flexibility is improved

It is recommended to use this method

src/com/mysql/mysql.properties configuration file content is as follows

url=jdbc:mysql://localhost:3306/test
user=root
password=123456

Connect to mysql Program

public void connection05() throws SQLException, ClassNotFoundException, IOException {
    // 使用Properties读取配置文件下的内容
    Properties properties = new Properties();
    properties.load(new FileInputStream("src/com/mysql/mysql.properties"));
    String url = properties.getProperty("url");
    String user = properties.getProperty("user");
    String password = properties.getProperty("password");
    // 得到mysql的连接
    Connection connection = DriverManager.getConnection(url, user, password);
    // 得到可以与mysql语句进行交互的对象
    Statement statement = connection.createStatement();
    // 关闭与 mysql语句进行交互的对象
    statement.close();
    // 关闭与 mysql语句进行交互的对象
    connection.close();
}

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