/*
* 得到Connection
* 1. 准备四大参数
* 2. 加载驱动类
* 3. 得到Connection
*/
String driverClassName = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://localhost:3306/ea";
String username = "root";
String password = "root";
// 加载驱动类
Class.forName(driverClassName);
// 使用DriverManager，以及省下的3个参数，得到Connection
Connection con = DriverManager.getConnection(url, username, password);
进阶
JdbcUtils.java
public class JdbcUtils {
private static Properties props = null;
// 只在JdbcUtils类被加载时执行一次！
static {
// 给props进行初始化，即加载dbconfig.properties文件到props对象中
try {
InputStream in = JdbcUtils.class.getClassLoader().getResourceAsStream("dbconfig.properties");
props = new Properties();
props.load(in);
} catch(IOException e) {
throw new RuntimeException(e);
}
// 加载驱动类
try {
Class.forName(props.getProperty("driverClassName"));
} catch (ClassNotFoundException e) {
throw new RuntimeException(e);
}
}
// 获取连接!
public static Connection getConnection() throws SQLException {
// 得到Connection
return DriverManager.getConnection(props.getProperty("url"),
props.getProperty("username"),
props.getProperty("password"));
}
}
使用
@Test
public void fun1() throws SQLException {
Connection con = JdbcUtils.getConnection();
System.out.println(con);
Connection con1 = JdbcUtils.getConnection();
System.out.println(con1);
}
