1 package it.cast.jdbc; 2  3 import java.sql.Connection; 4 import java.sql.DriverManager; 5 import java.sql.ResultSet; 6 import java.sql.SQLException; 7 import java.sql.Statement; 8  9 public class jdbcUtils {10 11     private static String url = "jdbc:mysql://localhost:3306/jdbc";12     private static String user = "root";13     private static String password = "123";14 15     private jdbcUtils() {16 17     }18 19     static {20         try {21             Class.forName("com.mysql.jdbc.Driver");22         } catch (ClassNotFoundException e) {23             e.printStackTrace();24         }25     }26 27     public static Connection getConnection() throws SQLException {28         return DriverManager.getConnection(url, user, password);29     }30 31     public static void free(ResultSet rs, Statement st, Connection conn) {32 33         try {34             if (rs != null)35                 rs.close();36         } catch (SQLException e) {37             e.printStackTrace();38         } finally {39 40             try {41                 if (st != null)42                     st.close();43             } catch (SQLException e) {44                 e.printStackTrace();45             } finally {46 47                 try {48                     if (conn != null)49                         conn.close();50                 } catch (SQLException e) {51                     e.printStackTrace();52                 }53             }54 55         }56 57     }58 }

 1 package it.cast.jdbc; 2  3 import java.sql.Connection; 4 import java.sql.ResultSet; 5 import java.sql.SQLException; 6 import java.sql.Statement; 7  8 public class Base { 9     10     static Connection conn = null;11 12     public static void main(String[] args) throws SQLException, ClassNotFoundException {13          test();14     }15 16     static void test() throws SQLException, ClassNotFoundException {17         18 19         // 2.建立连接20         conn = jdbcUtils.getConnection();21 22         // 3.创建语句23         Statement st = conn.createStatement();24 25         // 4.执行语句26         ResultSet rs = st.executeQuery("select * from user");27 28         // 5.处理结果29         while (rs.next()) {30             System.out.println(rs.getObject(1) + "\t" + rs.getObject(2) + "\t"31                     + rs.getObject(3)+"\t" + rs.getObject(4));32         }33         34         //6.释放资源35         jdbcUtils.free(rs, st, conn);36     }37 38 }