1、连接数据库

MySQL    com.mysql.jdbc.Driver , jdbc:mysql://localhost:3306/mydb

         创建Connection,Statement对象:

Class.forName("com.mysql.jdbc.Driver");con = DriverManager.getConnection(url, username, password);stat = con.createStatement();

   2、执行SQL语句

StringBuffer SQL = new StringBuffer("select * from user where ");String sign = "";if(user.getID() > 0){    SQL.append("ID = " + user.getID());    sign = " and ";    }if(user.getName() != null){    SQL.append(sign+"name = " + user.getName());    }rs = stat.executeQuery(SQL.toString());

   3、获取结果

while(rs.next()){    user.setID(rs.getLong("ID"));    user.setName(rs.getString("name"));    user.setPassword(rs.getString("password"));    ser.setRole(rs.getString("role"));    }

   4、关闭连接

public void closeConnect(){        try{            if(!con.isClosed()){                con.close();            }            if(!stat.isClosed()){                stat.close();            }            if(!rs.isClosed()){                rs.close();            }        }        catch (SQLException e){            e.printStackTrace();        }    }