checkgroup.java

《JSP程序设计实用教程》-梁建武-源代码-4567.rar

 package stu;

import java.sql.*;

public class checkGroup{
   String cour_id,stu_id;
   
   public void setCour_id(String id){cour_id=id;}	
   public String getCour_id(){return cour_id;}
   public void setStu_id(String id){stu_id=id;}
   public String getStu_id(){return stu_id;}
	
	
	public boolean isPre(){
		String a="";
     boolean ispre =false;
     String sql="select course.prepare from course where id='"+cour_id+"' ";
     sqlBean db = new sqlBean();
     try{
     ResultSet rs =db.executeQuery(sql);
     if(rs.next())
     {a=rs.getString("prepare");}
       }catch(SQLException ex){ 
      System.err.println("课程号查询有错误:"+ex.getMessage() ); 
      System.out.print("课程号查询有错误:"+ex.getMessage());//输出到客户端 
           }
        if(a.equals("0") )  
        {ispre=false;}
        else ispre=true;
		return ispre;
		}
	
  public boolean checkpre(){
  	boolean f=true;
  	if(isPre()){
   String	sql="select enrol.class_id "+
		"from enrol ,classes,course "+
		"where enrol.stu_id='"+stu_id+"' "+
 		"and course.id='"+cour_id+"' "+
 		"and course.prepare=classes.cour_id "+
 		"and enrol.class_id=classes.id  ";
	sqlBean db = new sqlBean();
     try{
	 ResultSet rs = db.executeQuery(sql);
    if(rs.next()) {f=true;} 
    else f=false;}
     catch(SQLException ex){ 
      System.err.println("课程号查询有错误:"+ex.getMessage() ); 
      System.out.print("课程号查询有错误:"+ex.getMessage());//输出到客户端 
           }     
      } 
   return f;
       }
  	 	            
	public boolean hasLogin(){   //检查该学生是否已经注册
  	boolean f=true;
   String sql="select stu_id,class_id "+
			"from enrol,classes "+
			"where stu_id='"+stu_id+"' "+
			"and classes.id=enrol.class_id "+
			"and cour_id='"+cour_id+"' ";
  	sqlBean db =new sqlBean();
  	try{
  	ResultSet rs=db.executeQuery(sql);
  	if(rs.next()){ f=false;}
  	else{ f=true;}
  	}catch(Exception e){ e.getMessage();}
  	return f;
  	                       }



	 public String getClassid(){
	 	String class_id=null;
	 	if(checkpre()){
	 	String sql="select classes.id from classes where cour_id='"+cour_id+"' ";	
  	 	sqlBean db = new sqlBean();
  	 	ResultSet rs = db.executeQuery(sql);
  	 	try{
	 	if(rs.next()){class_id=rs.getString("id"); }
	       }catch(SQLException ex){ 
      System.err.println("课程号查询有错误:"+ex.getMessage() ); 
      System.out.print("课程号查询有错误:"+ex.getMessage());//输出到客户端 
           }
          } else {class_id="error";}
             return class_id;
	 	}
  	 
  	 
  	 public String getTime(){
  	 	String class_id=getClassid();
  	 	String time="";
  	 	if(checkpre()){
  	    String	sql="select cour_time from classes where cour_id='"+cour_id+"'";    
        sqlBean db = new sqlBean();
  	 	ResultSet rs = db.executeQuery(sql);
  	 	try{
         if(rs.next()) { time=rs.getString("cour_time");}
           }catch(SQLException ex){ 
      System.err.println("查询有错误:"+ex.getMessage() ); 
      System.out.print("查询有错误:"+ex.getMessage());//输出到客户端 
           }
          } else{time="error";}
         return time;            	    
  	                  }	
  	 
  	 public String  getClassRoom(){
  	 	String class_id=getClassid();
  	 	String room="";
  	 	if(checkpre()){  	 
  	    String	sql="select room_id from classes where cour_id='"+cour_id+"'";
        sqlBean db = new sqlBean();
  	 	ResultSet rs = db.executeQuery(sql);
  	 	try{
         if(rs.next()) { room=rs.getString("room_id");}
           }catch(SQLException ex){ 
      System.err.println("课程号查询有错误:"+ex.getMessage() ); 
      System.out.print("课程号查询有错误:"+ex.getMessage());//输出到客户端 
           }
          } else {room="error";}
         return room;            
                              }
  	 	                    
  	 public void enrol(){
  	 	String class_id=null;
	if(checkpre()){
  	 		try{
  	 	String sql="select classes.id from classes where cour_id='"+cour_id+"' ";	
  	 	sqlBean db = new sqlBean();
  	 	ResultSet rs = db.executeQuery(sql);
  	 	if(rs.next()){class_id=rs.getString("id"); }
  	 	 
  	 	   }
  	 	   catch(SQLException ex){ 
  	 	 
      System.err.println("课程号查询有错误:"+ex.getMessage() ); 
      System.out.print("课程号查询有错误:"+ex.getMessage());//输出到客户端 
           }
          
            
            String sql="insert into enrol(stu_id,class_id,accept) "+
            " VALUES('"+stu_id+"','"+class_id+"','0')   ";
              sqlBean db = new sqlBean();
              db.executeInsert(sql); 
            }
               	 	
  	 
  	 			 	                }	                     
  	 	                     
}