代码语言：javascript复制
public static void ImageCodeMaker(){
// 定义图片的宽度和高度
int width = 90, height = 40;
// 创建一个图像对象
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
// 得到图像的环境对象
Graphics g = image.createGraphics();
g.setColor(getRandColor(180, 250));
g.fillRect(0, 0, width, height);
Random random = new Random();
for (int i = 0; i < 5; i ) {
g.setColor(getRandColor(50, 100));
int x = random.nextInt(width);
int y = random.nextInt(height);
g.drawOval(x, y, 4, 4);
}
// 设置字体，下面准备画随机数
g.setFont(new Font("", Font.PLAIN, 40));
// 随机数字符串
String sRand = "";
for (int i = 0; i < 4; i ) {
// 生成四个数字字符
String rand = getRandomChar();;
//String.valueOf(random.nextInt(10));
sRand = rand;
// 生成随机颜色
g.setColor(new Color(20 random.nextInt(80), 20 random
.nextInt(100), 20 random.nextInt(90)));
// 将随机数字画在图像上
g.drawString(rand, (17 random.nextInt(3)) * i 8, 34);
// 生成干扰线
for (int k = 0; k < 12; k ) {
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(9);
int yl = random.nextInt(9);
g.drawLine(x, y, x xl, y yl);
}
}
System.out.println(sRand);
}
private static String getRandomChar() {
String ret ="";
//数字和字母的组合
String baseNumLetter = "0123456789ABCDEFGHJKLMNOPQRSTUVWXYZ";
//纯数字
// String baseNum = "0123456789";
//纯字母
// String baseLetter = "ABCDEFGHJKLMNOPQRSTUVWXYZ";
// ret = baseLetter.charAt(new Random().nextInt(baseLetter.length())) "";
// ret = baseNum.charAt(new Random().nextInt(baseNum.length())) "";
ret = baseNumLetter.charAt(new Random().nextInt(baseNumLetter.length())) "";
return ret;
}
/**
* 产生一个随机的颜色
*
* @param fc
* 颜色分量最小值
* @param bc
* 颜色分量最大值
* @return
*/
public static Color getRandColor(int fc, int bc) {
Random random = new Random();
if (fc > 255){
fc = 255;
}
if (bc > 255){
bc = 255;
}
int r = fc random.nextInt(bc - fc);
int g = fc random.nextInt(bc - fc);
int b = fc random.nextInt(bc - fc);
return new Color(r, g, b);
}转载其他文章：
代码语言：javascript复制在页面显示时 需要如下代码：
// 首先设置页面不缓存
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
// 将生成的随机数字字符串写入Session
request.getSession(false).setAttribute("randcode", sRand);
// 使图像生效
g.dispose();
// 输出图像到页面
ImageIO.write(image, "JPEG", response.getOutputStream()); 
