java毕业设计之超市管理系统源码（前后端完整源代码）.zip

package db; import java.sql.*; public class db { private String dbDriver="com.mysql.jdbc.Driver"; private String sConnStr = "jdbc:mysql://localhost:3306/chaoshiguanli?useUnicode=true&characterEncoding=gb2312"; public Connection connect = null; public ResultSet rs=null; public db() { try { Class.forName(dbDriver).newInstance(); connect = DriverManager.getConnection(sConnStr,"root","root"); } catch (Exception ex) { System.out.println("12121"); } } public ResultSet executeQuery(String sql) { try{ connect=DriverManager.getConnection(sConnStr,"root","root"); Statement stmt=connect.createStatement(); rs=stmt.executeQuery(sql); }catch(SQLException ex){ System.err.println(ex.getMessage()); } return rs; } public void executeUpdate(String sql) { Statement stmt=null; rs=null; try { connect=DriverManager.getConnection(sConnStr,"root","root"); stmt=connect.createStatement(); stmt.executeUpdate(sql); stmt.close(); connect.close(); } catch(SQLException ex) { System.err.println(ex.getMessage()); } } }