JDBC详解及总结
首先,獲得數據庫的連接,獲得一個可配置的連接,是應用程序與數據庫的一個“握手”過程。
public class Test{public static void main(String[] args){Test test = new Test();test.list();}public void list(){DBUtil util = new DBUtil();Connection conn = util.getConnection();String sql = "select id, username, password from UserTbl";try{Statement stmt =conn.createStatement();ResultSet rs = stmt.executeQuery(sql);while(rs.next()){int id = rs.getInt("id");String username = rs.getString(2);String password = rs.getString(3);System.out.println(id+":"+username+":"+password);}}catch(SQLException e){e.printStackTrace();}finally{util.closeConnection(conn);}} }獲得數據庫連接的步驟:Class.forName加載驅動
--Class.forName("com.mysql.jdbc.Driver");
DriverManager獲得連接
--DriverManager.getConnection("jdbc:mysql://localhost:3306/xxxx_db","root","password");
public class DBUtil{public static void main(String[] args){DBUtil util = new DBUtil();//Connection conn = util.getConnection(); //前兩種辦法Connection conn = util.openConnection(); //第三種辦法}public Connection getConnection(){try{//這是第一種最簡陋的辦法//-----------------Class.forName("com.mysql.jdbc.Driver");return DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbc_db","root","password");//-----------------}catch(Exception e){e.printStackTrace();}return null;}public Connection getConnection(String url, String driver, String username, String password){try{//這是第二種辦法//-----------------Class.forName(driver);return DriverManager.getConnection(url, username, password);//-----------------}catch(Exception e){e.printStackTrace();}return null;}//第三種辦法,把數據庫信息寫入配置文件中,注意配置文件要保存在相應的工程包中//DBConfig.properties//文件中寫入://driver = com.mysql.jdbc.Driver//url = jdbc:mysql://localhost:3306/jdbc_db//username = root//password = passwordpublic Connection openConnecion(){Properties prop = new Properties();String username = null;String url = null;String driver = null;String password = null;try{prop.load(this.getClass().getClassLoader().getResourceAsStream("DBConfig.properties"));driver = prop.getProperty("driver");url = prop.getProperty("url");username = prop.getProperty("username");password = prop.getProperty("password");Class.forName(driver);return DriverManager.getConnection(url, username, password);}catch(Exception e){e.printStackTrace();}} }
commit, rollback
總結
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