userdao.java

本网站为学生管理网站

package students;
import java.sql.*;
public class UserDAO {
	static User user = new User();
	public static ResultSet queryUserByUsername(String username){
		

		Connection con = null;
		Statement stmt = null;
		ResultSet rs = null;
		try {
			con = Database.connectToDb();
			String strSQL = "select * from students where ID = '"+username+"'";
			stmt = con.createStatement();
			rs = stmt.executeQuery(strSQL);
			
		} catch (SQLException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		}
		
		return rs;
	}
	public static void AddUser(String stuid,String password, String name, 
			String sex, String enrollage, String enrollyear, String class1) {
		Connection con = null;
		Statement stmt = null;
		ResultSet rs = null;
		
		try {
			con = Database.connectToDb();
			String strSQL = "insert into students(ID,password,name,sex,enrollage,enrollyear,Class)"+"values('"+stuid+"','"+password+"','"+name+"','"+sex+"','"+enrollage+"','"+enrollyear+"','"+class1+"')";
			stmt = con.createStatement();
			stmt.executeUpdate(strSQL);
		}catch(SQLException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (con != null) {
				try {
					con.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
				con = null;
			}
		}
	}
	public static void Delete(String stuid){
		Connection con = null;
		Statement stmt = null;
		ResultSet rs = null;
		try {
			con = Database.connectToDb();
			String strSQL="delete from students where ID='"+stuid+"'";
			stmt = con.createStatement();
			
			stmt.executeUpdate(strSQL);
		}catch(SQLException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (con != null) {
				try {
					con.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
				con = null;
			}
		}
	}
	public static void AddCrouse(String cro_id,String cro_name,String cro_teacher,String cro_value,String cro_grade,String cro_dropyear){
		Connection con = null;
		Statement stmt = null;
		ResultSet rs = null;
		
		try {
			con = Database.connectToDb();
			String strSQL = "insert into crouses(cro_id, cro_name, cro_teacher, cro_value, cro_grade, cro_dropyear)"+"values('"+cro_id+"','"+cro_name+"','"+cro_teacher+"','"+cro_value+"','"+cro_grade+"','"+cro_dropyear+"')";
			stmt = con.createStatement();
			stmt.executeUpdate(strSQL);
		}catch(SQLException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (con != null) {
				try {
					con.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
				con = null;
			}
		}
	}
	public static void DeleteCrouse(String cro_id){
		Connection con = null;
		Statement stmt = null;
		ResultSet rs = null;
		try {
			con = Database.connectToDb();
			String strSQL="delete from crouses where cro_id='"+cro_id+"'"; 
			stmt = con.createStatement();
			
			stmt.executeUpdate(strSQL);
		}catch(SQLException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (con != null) {
				try {
					con.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
				con = null;
			}
		}
	}
	public static ResultSet select(String sql){
		Connection con = null;
		Statement stmt = null;
		ResultSet rs = null;
		
		try {
			con = Database.connectToDb();
			String strSQL = sql;
			stmt = con.createStatement();
			rs = stmt.executeQuery(strSQL);
		}catch(SQLException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		
		}
		return rs;
	}
	public static void update(String sql){
		Connection con = null;
		Statement stmt = null;
		
		
		try {
			con = Database.connectToDb();
			String strSQL = sql;
			stmt = con.createStatement();
			stmt.executeUpdate(strSQL);
		}catch(SQLException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (con != null) {
				try {
					con.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
				con = null;
			}
		}
		
	}
}