更新语句

String sql = "update student set num=?,name=?,birthday=?,score=?,password=? where id=?";
ps = conn.prepareStatement(sql);
ps.setString(1, student.getNum());
ps.setString(2, student.getName());
ps.setString(3, student.getBirthday2());
ps.setDouble(4, student.getScore());
ps.setString(5, student.getPassword());
ps.setInt(6, id);

删除

String sql="delete from student where id=?";
ps=conn.prepareStatement(sql);
ps.setInt(1, id);
ps.executeUpdate();

插入

String sql = "insert into student(num,name,birthday,score,password) values(?,?,?,?,?)";
ps = conn.prepareStatement(sql);
ps.setString(1, student.getNum());
ps.setString(2, student.getName());
ps.setDouble(4, student.getScore());
ps.setString(5, student.getPassword());
ps.setString(3, student.getBirthday2());

查询

String sql = "select * from student where num=? and password=?";
// 获取DB操作对象
ps = conn.prepareStatement(sql);
// 为动态参数赋值
ps.setString(1, num);
ps.setString(2, password);

javaweb中为mysql的curd多个值的语句