- 硬编码
public static void main(String[] args) throws SQLException {
String url = "jdbc:mysql://localhost:3306/test";
String user = "root";
String password = "123456";
//打开一个数据库连接。驱动管理器遍历所有注册过的驱动程序，以便找到一个能够使用数据库URL中指定的子协议的驱动程序。
//getConnection()方法返回一个与数据库连接的连接对象。
Connection connection = DriverManager.getConnection(url, user, password);
}
调试JDBC相关的问题，可以启用JDBC跟踪特性调用DriverManager.setLogWritter方法，可以将跟踪信息发送给PrintWriter，而PrintWriter将输出JDBC活动的详细列表。也可以添加到URL选项中。
- 使用配置文件
配置文件放在项目根目录下，配置如下：
### database.properties
jdbc.drivers=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/jd
jdbc.username=root
jdbc.password=123456
public static void main(String[] args) throws IOException {
try {
runTest();
} catch (SQLException e) {
for (Throwable t : e) {
t.printStackTrace();
}
}
}
public static void runTest() throws SQLException, IOException {
try (Connection conn = getConnection();
Statement stat = conn.createStatement()) {
stat.execute("CREATE TABLE Greetings (Message varchar(22))");
stat.execute("INSERT INTO Greetings Values('hello world')");
try (ResultSet resultSet = stat.executeQuery("SELECT * FROM Greetings")) {
if (resultSet.next()) {
System.out.println(resultSet.getString(1));
}
}
stat.executeUpdate("Drop table Greetings");
}
}
/**
* 从指定的database.properties文件中获取连接
*
* @return
*/
public static Connection getConnection() throws IOException, SQLException {
Properties props = new Properties();
try (InputStream in = Files.newInputStream(Paths.get("database.properties"))) {
props.load(in);
}
String drivers = props.getProperty("jdbc.drivers");
if (drivers != null) {
System.setProperty("jdbc.drivers", drivers);
}
String url = props.getProperty("jdbc.url");
String username = props.getProperty("jdbc.username");
String password = props.getProperty("jdbc.password");
Connection connection = DriverManager.getConnection(url, username, password);
return connection;
}
