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<>数据库连接方式
<>方式一
直接使用com.mysql.jdbc.Driver(),属于静态加载，灵活性差，依赖性强
推出方式2
public void connect01() throws SQLException { //创建dirver对象 Driver driver =new
Driver(); String url = "jdbc:mysql://localhost:3306/studb";
//用户名与密码放入properties对象 Properties properties = new Properties(); properties.
setProperty("user","root"); properties.setProperty("password","123456"); //建立连接
Connection connection= driver.connect(url,properties); System.out.println(
connection); }
<>方式二
利用反射加载Driver类，动态加载，更加灵活
public void connect02() throws ClassNotFoundException, InstantiationException,
IllegalAccessException, SQLException { Class<?> aClass = Class.forName(
"com.mysql.cj.jdbc.Driver"); Driver driver = (Driver) aClass.newInstance();
String url= "jdbc:mysql://localhost:3306/studb"; //用户名与密码放入properties对象
Properties properties= new Properties(); properties.setProperty("user","root");
properties.setProperty("password","123456"); //建立连接 Connection connection =
driver.connect(url,properties); System.out.println(connection); }
<>方式三
用DriverManager替代Driver进行统一管理,具有更好的扩展性
public void connect03() throws ClassNotFoundException, InstantiationException,
IllegalAccessException, SQLException { //利用反射加载Driver Class<?> aClass = Class.
forName("com.mysql.cj.jdbc.Driver"); Driver driver = (Driver) aClass.newInstance
(); //创建url和user和password String url = "jdbc:mysql://localhost:3306/studb";
String user= "root"; String password = "123456"; // 注册Driver驱动 DriverManager.
registerDriver(driver); Connection connection = DriverManager.getConnection(url,
user, password); System.out.println(connection); }
<>方式四
使用Class.forName 自动完成注册驱动，简化代码
是使用最多的
public void connect04() throws ClassNotFoundException, SQLException {
//利用反射加载Driver类 //在加载Driver类时，完成注册 /*源码 1.静态代码块，在类加载时，会执行一次
2.DriverManager.registerDriver(new Driver)); static { try {
DriverManager.registerDriver(new Driver()); } catch (SQLException var1) { throw
new RuntimeException("Can't register driver!"); } } } */ Class.forName(
"com.mysql.cj.jdbc.Driver"); //创建url，user，password String url =
"jdbc:mysql://localhost:3306/studb"; String user = "root"; String password =
"123456"; Connection connection = DriverManager.getConnection(url,user,password)
; System.out.println(connection); }
<>方式五
实际开发中比较好的，在方式4上改进，使用配置文件，连接数据库更加灵活
public void connect05() throws IOException, ClassNotFoundException,
SQLException{ //通过properties对象获取文件信息 Properties properties = new Properties();
properties.load(new FileInputStream("src\\Jdbc\\myjdbc\\mysql.properities"));
//获取相关的值 String user = properties.getProperty("user"); String url = properties.
getProperty("url"); String driver = properties.getProperty("driver"); String
password= properties.getProperty("password"); Class.forName(driver); Connection
connection= DriverManager.getConnection(url,user,password); System.out.println(
connection); }