java仿Servlet生成验证码实例详解

java仿Servlet生成验证码实例详解

实现原理：使用BufferedImage对象的Graphics来进行绘制，然后输出成一张图片进行保存

实现代码及详解:

public class validateCode{  private static Random rand = new Random();  public static void main(String[] args){    int val1 = rand.nextInt(9);    int val2 = rand.nextInt(9);    int val3 = rand.nextInt(9);    int val4 = rand.nextInt(9);    String val = val1 + " " + val2 + " " + val3 + " " + val4'    BufferedImage buf = drawImage(val);    //将最终的图片保存到D：//cheng.png下    Imageio.write(buf,"png",new File("D://cheng.png");  }  public static BufferedImage drawImage(String code){    int height = 30;    int width = 60;    BufferedImage buf = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);    Graphics2D gs = buf.createGraphics();    gs.setBackground(Color.black);    gs.drawRect(0,0,width,height);     //绘制随机干扰线    int total = 100;    drawRandLine(gs,total);    //绘制验证码    Font font = new Font("行楷",Font.BOLD,20);    gs.setFont(font);    gs.setColor(getRandColor(155,255));    gs.drawString(code,5,20);    return buf;  }  public static void drawRandLine(Graphics2D gs,int total){    for(int i=0; i<total; i++){      int x1 = rand.nextInt(width);      int x2 = rand.nextInt(width);      int y1 = rand.nextInt(height);      int y2 = rand.nextInt(height);      //设置随机颜色      gs.setColor(getRandColor(0,155));      gs.drawLine(x1,y1,x2,y2);    }    }  public static Color getRandColor(int from,int to){    int r = from + rand.nextInt(to-from);    int g = from + rand.nextInt(to-from);    int b = from + rand.nextInt(to-from);    return new Color(r,g,b);    }