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);
}