规范和封装jdbc程序代码

JDBC 部分方法引用工具类

 package it.cast.jdbc;

 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;

 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) {
             e.printStackTrace();
         }
     }

     public static Connection getConnection() throws SQLException {
         return DriverManager.getConnection(url, user, password);
     }

     public static void free(ResultSet rs, Statement st, Connection conn) {

         try {
             if (rs != null)
                 rs.close();
         } catch (SQLException e) {
             e.printStackTrace();
         } finally {

             try {
                 if (st != null)
                     st.close();
             } catch (SQLException e) {
                 e.printStackTrace();
             } finally {

                 try {
                     if (conn != null)
                         conn.close();
                 } catch (SQLException e) {
                     e.printStackTrace();
                 }
             }

         }

     }
 }

jdbcUtils

 package it.cast.jdbc;

 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;

 public class Base {

     static Connection conn = null;

     public static void main(String[] args) throws SQLException, ClassNotFoundException {
          test();
     }

     static void test() throws SQLException, ClassNotFoundException {

         // 2.建立连接
         conn = jdbcUtils.getConnection();

         // 3.创建语句
         Statement st = conn.createStatement();

         // 4.执行语句
         ResultSet rs = st.executeQuery("select * from user");

         // 5.处理结果
         while (rs.next()) {
             System.out.println(rs.getObject(1) + "\t" + rs.getObject(2) + "\t"
                     + rs.getObject(3)+"\t" + rs.getObject(4));
         }

         //6.释放资源
         jdbcUtils.free(rs, st, conn);
     }

 }

Base