java疯狂讲义习题，以实现要求功能，未加入智能算法，后续会做五子棋GUI程序，放出代码。
对初学者还是有点用的，第一次下五子棋赢电脑（random），哈哈！

import java.io.*;

class GobangTest 
{
    private static final int BOARD_SIZE = 15;
    private static String[][] chessBoard = new String[BOARD_SIZE][BOARD_SIZE];
    private static void init()//创建棋盘
    {
        for(String[] e : chessBoard)
            for(int i = 0;i < BOARD_SIZE;i++)
                e[i] = "╋";
    }
    
    private static void print()//绘制棋盘
    {
        for(String[] e : chessBoard)
        {
            for(String f : e)
                System.out.print(f);
            System.out.println();
        }
    }
    public static void main(String[] args) throws Exception 
    {
        init();
        print();
        System.out.println("请输入您要落子的坐标，以\"x,y\"的格式:");
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String inputStr = null;
        while((inputStr = br.readLine())!=null)
        {
            String[] posStrArr = inputStr.split(",");
            int xPos = Integer.parseInt(posStrArr[0]);
            int yPos = Integer.parseInt(posStrArr[1]);
            if(chessBoard[xPos-1][yPos-1]=="●"||chessBoard[xPos-1][yPos-1]=="○")
            {
                System.out.println("你这是要干撒？？？");
                continue;
            }
            chessBoard[xPos-1][yPos-1] = "●";
            int hNumRob=0,vNumRob=0,ldiaNumRob=0,rdiaNumRob=0,hNumPlay=0,vNumPlay=0,ldiaNumPlay=0,rdiaNumPlay=0;//胜负判断
            for(int i = 0;i<BOARD_SIZE;i++)
            {
                if(chessBoard[i][yPos-1]=="●")
                {
                    hNumPlay++;
                }
                else
                {
                    hNumPlay=0;
                }
                if(chessBoard[xPos-1][i]=="●")
                {
                    vNumPlay++;
                }
                else
                {
                    vNumPlay=0;
                }
                if(hNumPlay>=5||vNumPlay>=5)
                {
                    System.out.println("你赢了！！！");
                    init();
                    break;
                }
            }
            int posMin = (xPos>yPos)?yPos-1:xPos-1;
            for(int i = -posMin;xPos-1+i<BOARD_SIZE&&yPos-1+i<BOARD_SIZE;i++)
            {
                if(chessBoard[xPos-1+i][yPos-1+i] == "●")
                    rdiaNumPlay++;
                else
                    rdiaNumPlay=0;
                if(rdiaNumPlay>=5)
                {
                    System.out.println("你赢了！！！");
                    init();
                    break;
                }
            }
            posMin = (xPos-1>15-yPos)?15-yPos:xPos-1;
            for(int i = -posMin;xPos-1+i<BOARD_SIZE&&yPos-1-i>0;i++)
            {
                if(chessBoard[xPos-1+i][yPos-1-i] == "●")
                    ldiaNumPlay++;
                else
                    ldiaNumPlay=0;
                if(ldiaNumPlay>=5)
                {
                    System.out.println("你赢了！！！");
                    init();
                    break;
                }
            }
            int robotX,robotY;
            while(true)//使用随机数来充当对手，留待改进
            {
                robotX = (int)(Math.random()*BOARD_SIZE);
                robotY = (int)(Math.random()*BOARD_SIZE);
                if(chessBoard[robotX][robotY] != "●"&&chessBoard[robotX][robotY] != "○")
                {
                    chessBoard[robotX][robotY] = "○";
                    break;
                }
            }
            for(int i = 0;i<BOARD_SIZE;i++)
            {
                if(chessBoard[i][robotY]=="○")
                {
                    hNumRob++;
                }
                else
                {
                    hNumRob=0;
                }
                if(chessBoard[robotX][i]=="○")
                {
                    vNumRob++;
                }
                else
                {
                    vNumRob=0;
                }
                if(hNumRob>=5||vNumRob>=5)
                {
                    System.out.println("你输了！！！");
                    init();
                    break;
                }
            }
            int posXMin = (robotX>robotY)?robotY:robotX;
            for(int i = -posXMin;robotX+i<BOARD_SIZE&&robotY+i<BOARD_SIZE;i++)
            {
                if(chessBoard[robotX+i][robotY+i] == "○")
                    rdiaNumRob++;
                else
                    rdiaNumRob=0;
                if(rdiaNumRob>=5)
                {
                    System.out.println("你输了！！！");
                    init();
                    break;
                }
            }
            posXMin = (robotX>14-robotY)?14-robotY:robotX;
            for(int i = -posXMin;robotX+i<BOARD_SIZE&&robotY-i>=0;i++)
            {
                if(chessBoard[robotX+i][robotY-i] == "○")
                    ldiaNumRob++;
                else
                    ldiaNumRob=0;
                if(ldiaNumRob>=5)
                {
                    System.out.println("你输了！！！");
                    init();
                    break;
                }
            }
            print();
        }
    }
}