做了一個登陸驗證碼的生成小程序，或許對大家有用。支持背景圖和文字旋轉(zhuǎn)
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Date;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGEncodeParam;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
/**
* Servlet implementation class for Servlet: ImageGenerator
*
*/
public class ImageGenerator extends javax.servlet.http.HttpServlet implements
javax.servlet.Servlet {
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
response.setContentType("image/jpeg"); // 必須設(shè)置ContentType為image/jpeg
int length = 4; // 設(shè)置默認生成4個數(shù)字
Date d = new Date();
long lseed = d.getTime();
Random r = new Random(lseed); // 設(shè)置隨機種子
if (request.getParameter("length") != null) {
try {
length = Integer.parseInt(request.getParameter("length"));
} catch (NumberFormatException e) {
}
}
// 可以在此加入保存驗證碼的代碼
// 創(chuàng)建內(nèi)存圖像
BufferedImage bi = ImageIO.read(new File(this.getServletContext().getRealPath("./imgc.jpg")));
//可以在上面讀入一個背景圖，然后在背景圖上寫數(shù)字
Graphics2D g = bi.createGraphics();
g.setColor(Color.CYAN);
g.setFont(new Font(null, Font.BOLD, 15));
//旋轉(zhuǎn)
double rot;
for (int i = 0; i < length; i++) {
g.drawString(String.valueOf(r.nextInt(9)), bi.getWidth()/4 + i * 15, bi.getHeight()/2);
rot = r.nextDouble() * 0.1;
if(r.nextBoolean())
rot = -1 * rot;
g.rotate(rot);
}
try {
// 使用JPEG編碼，輸出到response的輸出流
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(response
.getOutputStream());
JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(bi);
param.setQuality(1.0f, false);
encoder.setJPEGEncodeParam(param);
encoder.encode(bi);
} catch (Exception ex) {
}
}
}
自己配置一下背景圖片的位置就可以了
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