java生成验证码图片

public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        BufferedImage image = new BufferedImage(100, 100,
                BufferedImage.TYPE_INT_RGB);
        Graphics g = image.getGraphics();
        // 1.设置背景色
        setBackGround(g);

        // 2.设置边框
        setBorder(g);

        // 3.画干扰线
        drawRandomLine(g);

        // 4.写随机数
        drawRandomNum(g);

        // 5.图形写给浏览器
        response.setContentType("image/jpeg");
        ImageIO.write(image, "jpg", response.getOutputStream());

    }

    private void drawRandomNum(Graphics g) {
        g.setColor(Color.RED);
        g.setFont(new Font("宋体",Font.BOLD,20));
        //所有汉字区间 u4e00 u9fa5
        for (int i = 0; i < 4; i++) {
            int r=new Random().nextInt(100);
            int r2=new Random().nextInt(100);
            g.drawString("好", r, r2);
        }

    }

    private void drawRandomLine(Graphics g) {
        g.setColor(Color.GREEN);
        for (int i = 0; i < 5; i++) {
            int x1 = new Random().nextInt(100);
            int y1 = new Random().nextInt(100);
            int x2 = new Random().nextInt(100);
            int y2 = new Random().nextInt(100);
            g.drawLine(x1, y1, x2, y2);
        }
    }

    private void setBorder(Graphics g) {
        g.setColor(Color.BLUE);
        g.drawRect(1, 1, 98, 98);
    }

    private void setBackGround(Graphics g) {
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, 100, 100);
    }