根据responseServlet生成图片验证码
代码：
前端代码为：
运行结果还行：
package com.babyDuncan.response;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
public class indentity extends HttpServlet {
public static final char[] CHARS = { '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'f', 'k', 'r', 'y' };
public static Random random = new Random();
public static String getRandomStriong() {
StringBuffer sb = new StringBuffer();
for (int i = 0; i < 6; i++) {
sb.append(CHARS[random.nextInt(CHARS.length)]);
}
return sb.toString();
}
public static Color getRandomColor(){
return new Color(random.nextInt(255),random.nextInt(255),random.nextInt(255));
}
public static Color getOtherColor(Color c){
return new Color(255-c.getRed(),255-c.getGreen(),255-c.getBlue());
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("image/jpeg");
String randomString = getRandomStriong();
this.log(randomString);
request.getSession(true).setAttribute("randomString", randomString);
int width = 100;
int heigth = 30;
Color color = getRandomColor();
Color otherColor = getOtherColor(color);
BufferedImage bi = new BufferedImage(width,heigth,BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
g.setFont(new Font(Font.SANS_SERIF,Font.BOLD,16));
g.setColor(color);
g.fillRect(0,0,width,heigth);
g.setColor(otherColor);
g.drawString(randomString, 18, 20);
for(int i=0;i<random.nextInt(100);i++){
g.drawRect(random.nextInt(width), random.nextInt(heigth), 1, 1);
}
ServletOutputStream out = response.getOutputStream();
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(bi);
out.flush();
}
}
前端代码为：
<body>
<script type="text/javascript">
function reloadImage(){
document.getElementById("btn").disabled = true;
document.getElementById("inditity").src = "servlet/indentity?ts="+
new Date().getTime();
}
</script>
<image src="servlet/indentity" id="inditity" onload="btn.disabled=false;"> </image>
<input type="button" value="换张图片" id="btn" onclick="reloadImage()"/>
</body>
运行结果还行：