Java开发学生管理系统-project

package stu; import java.sql.ResultSet; import java.sql.SQLException; //例外 public class ControlMysql { private static String SqlStatement; //准备声明 private static ConnectMysql database; //建立数据库的连接 private static ResultSet resultSet; //用于存储结果集 private final static String tab = "\t\t"; private static boolean flog = false; //flog用来标记是否有这个老师的id public static int SumOfTeacher(){ //得到老师的数量 SqlStatement = "select count(tid) from tea;"; //查询语句不多说 database = new ConnectMysql(SqlStatement); //前边的写的连接类, 里边的是准备执行的语句 try{ resultSet = database.pStatement.executeQuery(); //这里的executeQuery函数是说执行的是一个查询语句, 然后呢用resultset 来存储它返回的结果集 resultSet.next(); //resultset存储的貌似是从null开始的, 也就是说resultset 是一个空头指针似的只有指向下一个信息块才能正常使用 return resultSet.getInt(1); //得到结果集的第1列(select count(tid) from tea;这个返回的是一个int类型数字而且我们需要的是一个int类型的数据,所以用getint方法) } //这里getInt(1)为什么为什么不是getInt(0) 呢 找到源码的注释是这样的:columnIndex the first column is 1, the second is 2 catch (Exception e) { e.printStackTrace(); } MysqlClose(1); return 0; } public static int SumOfStudent(){ //得到学生的数量 SqlStatement = "select count(sid) from stu;"; database = new ConnectMysql(SqlStatement); try{ resultSet = database.pStatement.executeQuery(); resultSet.next(); return resultSet.getInt(1); } catch (Exception e) { e.printStackTrace(); } MysqlClose(1); //关闭连接(我自己写的)如果用到了结果集也就是说是查询操作的参数就写1,因为1 被我规定为 resultSet.close(); database.close(); return 0; } public static Teacher gettea(String ID, String pass){ //得到老师的信息,返回一个教师类的数据 SqlStatement = "select * from tea;"; database = new ConnectMysql(SqlStatement); String id = null, password = null, name = null, sex = null, birthday = null, position = null; try{ resultSet = database.pStatement.executeQuery(); while(resultSet.next()){ if(resultSet.getString(1).equals(ID)){ flog = true; //flog用来标记是否有这个老师的id if(resultSet.getString(2).equals(pass)){ id = resultSet.getString(1); password = resultSet.getString(2); name = resultSet.getString(3); sex = resultSet.getString(4); birthday = resultSet.getString(5); position = resultSet.getString(6); // System.out.println(id + tab + password + tab + name + tab + sex + tab + birthday + tab + position); } else { System.out.println("Wrong Password!"); } } } if(!flog) System.out.println("No This ID!"); } catch(SQLException e){ e.printStackTrace(); } MysqlClose(1); return new Teacher(id, password, name, sex, birthday, position); } public static Student getstu(String ID, String pass){ SqlStatement = "select * from stu;"; database = new ConnectMysql(SqlStatement); String id = null, password = null, name = null, sex = null, birthday = null, major = null; try{ resultSet = database.pStatement.executeQuery(); while(resultSet.next()){ //前边忘了写了resultSet.next() 返回的是一个Boolean类型的变量值, 如果下一个数据为空就返回false不然就是true if(resultSet.getString(1).equals(ID)){ //验证id flog = true; if(resultSet.getString(2).equals(pass)){ id = resultSet.getString(1); password = resultSet.getString(2); name = resultSet.getString(3); sex = resultSet.getString(4); birthday = resultSet.getString(5); major = resultSet.getString(6); // System.out.println(id + tab + password + tab + name + tab + sex + tab + birthday + tab + major); } else { System.out.println("Wrong Password!"); } } } if(!flog) System.out.println("No This ID!"); } catch(SQLException e){ e.printStackTrace(); } MysqlClose(1); return new Student(id, password, name, sex, birthday, major); } public static boolean addStudent(Student stu){ String id = stu.getID(), password = stu.getPassword(), name = stu.getName(), sex = stu.getSex(), birthday = stu.getbirthday(), major = stu.getmajor(); System.out.println(id); System.out.println(password); System.out.println(name); System.out.println(sex); System.out.println(birthday); System.out.println(major); SqlStatement = "insert into stu(sid, spassword, sname, ssex, sbirthday, smajor)" + "select '"+ id +"','" + password + "','" + name + "','" + sex + "','" + birthday + "','" + major + "';"; database = new ConnectMysql(SqlStatement); System.out.println(SqlStatement); try{ database.pStatement.executeUpdate(); } catch(SQLException e){ e.printStackTrace(); return false; } MysqlClose(2); return true; } public static boolean addTeacher(Teacher tea){ String id = tea.getID(), password = tea.getPassword(), name = tea.getName(), sex = tea.getSex(), birthday = tea.getbirthday(), position = tea.getPosition(); System.out.println(id); System.out.println(password); System.out.println(name); System.out.println(sex); System.out.println(birthday); System.out.println(position); SqlStatement = "insert into tea(tid, tpassword, tname, tsex, tbirthday, tposition)" + "select '"+ id +"','" + password + "','" + name + "','" + sex + "','" + birthday + "','" + position + "';"; database = new ConnectMysql(SqlStatement); System.out.println(SqlStatement); try{ database.pStatement.executeUpdate(); } catch(SQLException e){ e.printStackTrace(); return false; } MysqlClose(2); //这里关闭连接的参数是2 , 没有用到结果集所以只有database.close(); return true; } public static Student getOnestu(String ID){ SqlStatement = "select * from stu where sid = '" + ID + "';"; database = new ConnectMysql(SqlStatement); String id = null, password = null, name = null, sex = null, birthday = null, major = null; try{ resultSet = database.pStatement.executeQuery(); while(resultSet.next()){ if(resultSet.getString(1).equals(ID)){ flog = true; id = resultSet.getString(1); password = resultSet.getString(2); name = resultSet.getString(3); sex = resultSet.getString(4); birthday = resultSet.getString(5); major = resultSet.getString(6); } } if(!flog) System.out.println("No This ID!"); } catch(SQLException e){ e.printStackTrace(); } MysqlClose(1); return new Student(id, password, name, sex, birthday, major); } public static Student[] getSomestus(int sum){ SqlStatement = "select * from stu;"; database = new ConnectMysql(SqlStatement); int i = 0; String id = null, password = null, name = null, sex = null, birthday = null, major = null; Student []stus; stus= new Student[sum]; try{ resultSet = database.pStatement.executeQuery(); while(resultSet.next() && i < sum){ flog = true; id = resultSet.getString(1); password = resultSet.getString(2); name = resultSet.getString(3); sex = resultSet.getString(4); birthday = resultSet.getString(5); major = resultSet.getString(6); stus[i++] = new Student(id, password, name, sex, birthday, major); } } catch(SQLException e){ e.printStackTrace(); } MysqlClose(1); return stus; } public static void MysqlClose(int ok){ if(1 == ok){ try{ resultSet.close(); database.close(); } catch(SQLException e){ e.printStackTrace(); } } else if(2 == ok){ try{ database.close(); } catch(Exception e){ e.printStackTrace(); } } } }