After End Of Result set error?

[mrhid6]

ok so i have a problem with a database connection here is the query and the error i get please help

    public String getonlineplayer(int mapid,int pid){
        String returnstring ="";
        if(mapid>0 && pid!=0){
            try{
                pst = con.prepareStatement("select * from players where areaid='"+mapid+"' and online='1' and ID!='"+pid+"'");
                rs = pst.executeQuery();
                while(rs.next()){
                    if(rs!=null){
                        returnstring += "username="+rs.getString("uname")+
                        ",xpos="+rs.getInt("xpos")+",ypos="+rs.getInt("ypos")+",playerimage="+rs.getInt("playerimage")+"#";
                    }else{
                        break;
                    }
                }
            }catch(Exception e){
                e.printStackTrace();
            }
        }
        return returnstring;
    }

java.sql.SQLException: After end of result set
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:987)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:982)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:927)
	at com.mysql.jdbc.ResultSetImpl.checkRowPos(ResultSetImpl.java:841)
	at com.mysql.jdbc.ResultSetImpl.getInt(ResultSetImpl.java:2674)
	at com.mysql.jdbc.ResultSetImpl.getInt(ResultSetImpl.java:2815)
	at Mysql.getonlineplayer(Mysql.java:95)
	at EchoServer$ClientServiceThread.run(EchoServer.java:173)

[JosAH]

Which line is line #95 in your code?

kind regards,

Jos

[mrhid6]

ok so it is this "returnstring += "username="+rs.getString("uname") ... "

[JosAH]

ok so it is this "returnstring += "username="+rs.getString("uname") ... "

Are you fetching those columns from left to right in database table order? Some RDBMSs don't like it when you fetch columns from a row out of order.

kind regards,

Jos

[mrhid6]

ok i have altered some of the code in order of left to right

   public String getonlineplayer(int mapid,int pid){
        String returnstring ="";
        if(mapid>0 && pid!=0){
            try{
                pst = con.prepareStatement("select * from players where areaid='"+mapid+"' and online='1' and ID!='"+pid+"'",ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
                rs = pst.executeQuery();
                if(rs.next()){
                    do{
                        if(rs!=null){
                            
                            String uname = rs.getString("uname");
                            String pimage = rs.getString("playerimage");
                            String xpos = rs.getString("xpos");
                            String ypos = rs.getString("ypos");
                            
                            returnstring += "username="+uname+
                            ",xpos="+xpos+",ypos="+ypos+",playerimage="+pimage+"#";
                        }else{
                            break;
                        }
                    }while(rs.next());
                }
            }catch(Exception e){
                e.printStackTrace();
            }
        }
        return returnstring;
    }

its giving me line 97 which is "String pimage = rs.getString("playerimage");"

[JosAH]

its giving me line 97 which is "String pimage = rs.getString("playerimage");"

Same exception? Is there another dbms client that is updating your table?

kind regards,

Jos

[mine0926]

before while loop, try to put rs.beforeFirst().

Also remove the if condition before you do while loop because you are skipping one record by doing that.

[JosAH]

before while loop, try to put rs.beforeFirst().

Also remove the if condition before you do while loop because you are skipping one record by doing that.

The beforeFirst() call should't be needed; from the API documentation of the next() method:

Moves the cursor froward one row from its current position. A ResultSet cursor is initially positioned before the first row; the first call to the method next makes the first row the current row; the second call makes the second row the current row, and so on.

The first call to next() positions the ResultSet at the first row (if any).

kind regards,

Jos

[mrhid6]

ok i have done all the changes you said but nothing still error forgot to say that the function is in a thread which is contanstly calling the method if that help? here is code

   public String getonlineplayer(int mapid,int pid){
        String returnstring ="";
        if(mapid>0 && pid!=0){
            try{
                pst = con.prepareStatement("select * from players where areaid='"+mapid+"' and online='1' and ID!='"+pid+"'",ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
                rs = pst.executeQuery();
                rs.beforeFirst();
                while(rs.next()){

                    String uname = rs.getString("uname");
                    int pimage = rs.getInt("playerimage");
                    int  xpos = rs.getInt("xpos");
                    int ypos = rs.getInt("ypos");

                    returnstring += "username="+uname+
                    ",xpos="+Integer.toString(xpos)+",ypos="+Integer.toString(ypos)+",playerimage="+Integer.toString(pimage)+"#";
                }
            }catch(Exception e){
                e.printStackTrace();
                System.out.println("["+pid+"]Online Players Error While Validating "+e);
            }
        }
        return returnstring;
    }

[JosAH]

ok i have done all the changes you said but nothing still error forgot to say that the function is in a thread which is contanstly calling the method if that help?

Sure, that helps; make that method a synchronized method so that it only runs once at a certain moment in time.

kind regards,

Jos

[mrhid6]

Sure, that helps; make that method a synchronized method so that it only runs once at a certain moment in time.

thanks for reply and how can i do this?

[JosAH]

thanks for reply and how can i do this?

synchronized public String getonlineplayer(int mapid,int pid) { ... }

kind regards,

Jos

[Tolls]

Since this is multi-threaded I hope that your statment and resultset objects are local to this method.

Since it is clear they are not I would suggest you change that, as that is the cause (almost certainly) of your problem.
Synchronising this method will only be a sticky-tape fix, as you'll use up your db cursors before too long.

[mrhid6]

Ok got it sorted did what u said about the synchronized method and it has solved my problems thanks all! :)

[Tolls]

That isn't the solution.
You've merely hidden the real bug, which is sharing your resources like that..