1.在src下建立一個jdbc.properties檔案

url=jdbc:mysql:///demo
user=root
password=123
driver=com.mysql.jdbc.Driver

2.編寫工具類

public class JdbcUtil {
    private static Connection con = null;
    private static String url;
    private static String user;
    private static String password;
    private static String driver;
    
 
static{
        Properties p = new Properties();//建立Properties集合物件
        InputStream res = JdbcUtil.class  //利用類載入器獲取到該配置檔案，他的預設路徑是從src下尋找，返回一個輸入流
                .getClassLoader()
                .getResourceAsStream("jdbc.properties");
        try {
            p.load(res);  //載入配置檔案
            url = p.getProperty("url"); //獲取配置檔案中的值
            user 
 
= p.getProperty("user");
            password = p.getProperty("password");
            driver = p.getProperty("driver");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 獲取連線
     * @return
     */
    public static Connection getConnection(){
        
 
try {
            Class.forName(driver);
            con = DriverManager.getConnection(url, user, password);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return con;
    }

    /**
     * 關閉連線
     * @param stmt
     * @param con
     */
    public static void close(Statement stmt,Connection con){
        if(stmt!=null){
            try {
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(con!=null){
            try {
                con.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}