使用properties文件配置数据库驱动，uri，用户名和密码；以便于日后更换数据库不用更改源代码；

driver=com.mysql.jdbc.Driveruri=jdbc:mysql://localhost:3306/day10user=rootpassword=root

 

1.注册驱动

1 public static Connection getConn() throws FileNotFoundException, IOException, ClassNotFoundException, SQLException{2         3         Class.forName(prop.getProperty("driver"));4         return DriverManager.getConnection(prop.getProperty("uri"),prop.getProperty("user"),prop.getProperty("password"));5         6         7     }

 

2.创建连接器

Connection conn = JDBCUtils.getConn();//Connection conn = DriverMananger("uri,user,password");

 

3.获取传输器

Statment stat = conn.createStatement();

 

5.利用传输器查询语句，并返回结果集

stat.executeUpdate(sql); 增删改

stat.executeQuery(sql);查询语句

6.关闭资源

1 public static void close(Connection conn,Statement stat,ResultSet rs){ 2          3             if(rs!=null){ 4                 try { 5                     rs.close(); 6                 } catch (SQLException e) { 7                     throw new RuntimeException(e); 8                      9                 }finally{10                     rs=null;11                 }12             }13             if(stat!=null){14                 try {15                     stat.close();16                 } catch (SQLException e) {17                     throw new RuntimeException(e);18                     19                 }finally{20                     stat=null;21                 }22             }23             if(conn!=null){24                 try {25                     conn.close();26                 } catch (SQLException e) {27                     throw new RuntimeException(e);28                     29                 }finally{30                     conn=null;31                 }32             }33     }

最后 使用预编译语句可防止SQL语句的注入问题，preparestatment

1 String sql = "select * from user where username=?and password =?";2 ps = conn.prepareStatement(sql);3 ps.setString(1, username);4 ps.setString(2, password);5 rs = ps.executeQuery();