JDBC小小執行個體教程

public class Base {public static void main(String[] args) throws Exception {// TODO Auto-generated method stubtemplate();}static void template() throws Exception{Connection conn=null;Statement st=null;ResultSet resultset=null;try {//2.建立串連conn=JdbcUtils.getConnection();//3.建立語句st=conn.createStatement();//4.執行語句resultset=st.executeQuery("select *from user");//5.處理結果while(resultset.next()){System.out.println(resultset.getObject(1));System.out.println(resultset.getObject(2));System.out.println(resultset.getObject(3));System.out.println(resultset.getObject(4));}} finally{JdbcUtils.free(resultset, st, conn);}}}public class JdbcUtils {private static String url="jdbc:mysql://localhost:3306/jdbc";private static String user="root";private static String password="123";private JdbcUtils(){}static{try{Class.forName("com.mysql.jdbc.Driver");}catch(ClassNotFoundException e){throw new ExceptionInInitializerError(e);}}public static Connection getConnection() throws SQLException{return DriverManager.getConnection(url, user, password);}public static void free(ResultSet resultset,Statement st,Connection conn){//6.釋放資源try{if(resultset!=null)resultset.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}finally{try{if(st!=null)st.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}finally{if(conn!=null)try {conn.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}}}