import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.util.Random;
import org.apache.commons.lang3.StringUtils;
/**
* 图片验证码类
*/
public class Captcha {
private int width = 100;
private int height = 30;
private Random random = new Random();
private BufferedImage image;
/** 验证码图片上显示的字符 */
private String code;
/** 波形的幅度倍数，越大扭曲的程序越高，一般为3 */
private int twistLevel = 2;
/** 干扰线数量 */
private int noiseLineNumber = 3;
/** 背景色 */
private Color backgroundColor = Color.WHITE;
/** 字体颜色 */
// private Color foregroundColor = Color.BLACK;
private Color[] colors = { Color.BLUE, Color.RED, Color.GREEN, Color.BLACK, Color.CYAN, Color.MAGENTA };
private Color getRandomColor() {
return colors[random.nextInt(colors.length)];
}
/**
* @param width
* - 验证码图片宽度
* @param height
* - 验证码图片高度
* @param randomStr
* - 随机字符串
* @return
*/
public Captcha generate(int width, int height, String randomStr) {
this.width = width;
this.height = height;
this.code = randomStr;
if (StringUtils.isBlank(code)) {
throw new RuntimeException("randomStr can not be empty.");
}
int xWidth = width / (code.length() + 2);
int yIndex = height - 4;
Graphics2D graphics = graphicsInit();
for (int i = 0; i < code.length(); i++) {
// graphics.setColor(foregroundColor);
graphics.setColor(getRandomColor());
graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
graphics.drawString(code.charAt(i) + "", (i + 1) * xWidth, yIndex);
}
setBuffImg(disturb());
return this;
}
private Graphics2D graphicsInit() {
Graphics2D graphics = buffImgInit().createGraphics();
graphics.setColor(backgroundColor);
graphics.fillRect(0, 0, width, height);
graphics.setFont(new Font("Fixedsys", Font.ITALIC, height - 2));
graphics.drawRect(0, 0, width - 1, height - 1);
return graphics;
}
private BufferedImage buffImgInit() {
image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
return image;
}
private BufferedImage disturb() {
drawNoiseLine(image.createGraphics());
return twistImage();
}
private void drawNoiseLine(Graphics2D graphics) {
int x = 0;
int y = 0;
int xl = 0;
int yl = 0;
for (int i = 0; i < noiseLineNumber; i++) {
x = random.nextInt(width * 2 / 3);
y = random.nextInt(height * 2 / 3);
xl = random.nextInt(width / 2);
yl = random.nextInt(height / 2);
// graphics.setColor(foregroundColor);
graphics.setColor(getRandomColor());
graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
graphics.drawLine(x, y, x + xl, y + yl);
}
}
private BufferedImage twistImage() {
double dMultValue = random.nextInt(9) + twistLevel;
double dPhase = random.nextInt(6);// 波形的起始相位，取值区间（0-2＊PI）
BufferedImage destBi = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_INT_RGB);
Graphics2D graphics = destBi.createGraphics();
graphics.setColor(backgroundColor);
graphics.fillRect(0, 0, width, height);
for (int i = 0; i < destBi.getWidth(); i++) {
for (int j = 0; j < destBi.getHeight(); j++) {
int nOldX = getXPosition4Twist(dPhase, dMultValue, destBi.getHeight(), i, j);
int nOldY = j;
if (nOldX >= 0 && nOldX < destBi.getWidth() && nOldY >= 0 && nOldY < destBi.getHeight()) {
destBi.setRGB(nOldX, nOldY, image.getRGB(i, j));
}
}
}
return destBi;
}
private int getXPosition4Twist(double dPhase, double dMultValue, int height, int xPosition, int yPosition) {
double PI = Math.PI; // 此值越大，扭曲程度越大
double dx = (double) (PI * yPosition) / height + dPhase;
double dy = Math.sin(dx);
return xPosition + (int) (dy * dMultValue);
}
public BufferedImage getImage() {
return image;
}
public void setBuffImg(BufferedImage buffImg) {
this.image = buffImg;
}
public int getWidth() {
return width;
}
public void setWidth(int width) {
this.width = width;
}
public int getHeight() {
return height;
}
public void setHeight(int height) {
this.height = height;
}
}
使用示例：
Java代码 收藏代码
String randomStr = RandomStringUtils.randomAlphabetic(4).toLowerCase();
request.getSession().setAttribute(KEY_CAPTCHA, randomStr);
BufferedImage bi = new Captcha().generate(200, 50, randomStr).getImage();
ByteArrayOutputStream bos = new ByteArrayOutputStream();
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(bos);
encoder.encode(bi);
ImageIO.write(bi, "JPEG", response.getOutputStream());
转载于:https://www.cnblogs.com/iamconan/p/7383437.html
相关资源：Java生成图片验证码
