短信验证码生成工具类

public class ImageCodeUtil {
/**
* 验证码难度级别 Simple-数字 Medium-数字和小写字母 Hard-数字和大小写字母
/
public enum SecurityCodeLevel {
Simple, Medium, Hard
};
/*
* 产生默认验证码，4位中等难度
*
* @return
/
public static String getSecurityCode() {
return getSecurityCode(4, SecurityCodeLevel.Medium, false);
}
/*
* 产生长度和难度任意的验证码
*
* @param length
* @param level
* @param isCanRepeat
* @return
/
public static String getSecurityCode(int length, SecurityCodeLevel level, boolean isCanRepeat) {
// 随机抽取len个字符
int len = length;
// 字符集合（–除去易混淆的数字0,1,字母l,o,O）
char[] codes = {
‘0’, ‘1’, ‘2’, ‘3’, ‘4’, ‘5’, ‘6’, ‘7’, ‘8’, ‘9’,
‘a’, ‘b’, ‘c’, ‘d’, ‘e’, ‘f’, ‘g’, ‘h’, ‘i’, ‘j’, ‘k’, ‘l’, ‘m’, ‘n’, ‘o’, ‘p’, ‘q’, ‘r’, ‘s’, ‘t’, ‘u’, ‘v’, ‘w’, ‘x’, ‘y’, ‘z’,
‘A’, ‘B’, ‘C’, ‘D’, ‘E’, ‘F’, ‘G’, ‘H’, ‘I’, ‘J’, ‘K’, ‘L’, ‘M’, ‘N’, ‘O’, ‘P’, ‘Q’, ‘R’, ‘S’, ‘T’, ‘U’, ‘V’, ‘W’, ‘X’, ‘Y’, ‘Z’
};
// 根据不同难度截取字符串
if (level == SecurityCodeLevel.Simple) {
codes = Arrays.copyOfRange(codes, 0, 10);
} else if (level == SecurityCodeLevel.Medium) {
codes = Arrays.copyOfRange(codes, 0, 36);
}
// 字符集和长度
int n = codes.length;
// 抛出运行时异常
if (len > n && isCanRepeat == false) {
throw new RuntimeException(String.format(“调用SecurityCode.getSecurityCode(%1$s,$s,%3$s)出现异常，"+"当isCanRepeat为$s时，传入参数%1$s不能大于$s”, len, level, isCanRepeat, n));
}
// 存放抽取出来的字符
char[] result = new char[len];
// 判断能否出现重复字符
if (isCanRepeat) {
for (int i = 0; i < result.length; i++) {
// 索引0 and n-1
int r = (int) (Math.random() * n);
// 将result中的第i个元素设置为code[r]存放的数值
result[i] = codes[r];
}
} else {
for (int i = 0; i < result.length; i++) {
// 索引0 and n-1
int r = (int) (Math.random() * n);
// 将result中的第i个元素设置为code[r]存放的数值
result[i] = codes[r];
// 必须确保不会再次抽取到那个字符，这里用数组中最后一个字符改写code[r],并将n-1
codes[r] = codes[n - 1];
n–;
}
}
return String.valueOf(result);
}
/*
* 生成验证码图片

 * @param securityCode

 * @return

 */
public static BufferedImage createImage(String securityCode){

    int codeLength = securityCode.length();//验证码长度

    int fontSize = 18;//字体大小

    int fontWidth = fontSize+1;

    //图片宽高

    int width = codeLength*fontWidth+6;
    int height = fontSize*2+1;
    //图片

    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

    Graphics2D g = image.createGraphics();

    g.setColor(Color.WHITE);//设置背景色

    g.fillRect(0, 0, width, height);//填充背景

    g.setColor(Color.LIGHT_GRAY);//设置边框颜色

    g.setFont(new Font("Arial", Font.BOLD, height-2));//边框字体样式

    g.drawRect(0, 0, width-1, height-1);//绘制边框

    //绘制噪点

    Random rand = new Random();

    g.setColor(Color.LIGHT_GRAY);

    for (int i = 0; i < codeLength*6; i++) {

        int x = rand.nextInt(width);

        int y = rand.nextInt(height);

        g.drawRect(x, y, 1, 1);//绘制1*1大小的矩形

    }

    //绘制验证码

    int codeY = height-10;

    g.setColor(new Color(19,148,246));

    //Georgia  是个字体，如果想用中文要指定中文字体；eg:"宋体";
    //g.setFont(new Font("Georgia", Font.BOLD, fontSize));
    g.setFont(new Font("宋体", Font.BOLD, fontSize));
    for(int i=0;i<codeLength;i++){
        double deg=new Random().nextDouble()*20;
        g.rotate(Math.toRadians(deg), i*16+13,codeY-7.5);
        g.drawString(String.valueOf(securityCode.charAt(i)), i*16+5, codeY);
        g.rotate(Math.toRadians(-deg), i*16+13,codeY-7.5);
    }

    g.dispose();//关闭资源

    return image;

}

//测试
public static void main(String[] args) throws IOException{
    //获得随机字符
    String securityCode = getSecurityCode();
    //打印随机字符
    System.out.println("===="+securityCode);
    //生成图片

// BufferedImage image = createImage(securityCode);
//将生成的验证码图片以png(1.png)的格式输出到D盘 “D:\1.png” == “D:/1.png”
// ImageIO.write(image, “png”, new FileOutputStream(new File(“D:\4.png”)));
}

}