Struts实现验证码

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Random;
import com.sun.image.codec.jpeg.ImageFormatException;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

//定义一个工具人，用于产生验证码图片
public class SecurityCode {
public static final int WIDTH = 100;
public static final int HEIGHT = 25;
public static String checkstring ;

//得到验证码的BtyArrayInputStream流
public static ByteArrayInputStream getImageAsInputStream()
{
BufferedImage image = getRandomImage();
return convertImageToStream(image);
}

//得到验证码图片
public static BufferedImage getRandomImage() {
BufferedImage randomImage = new BufferedImage(WIDTH, HEIGHT,
BufferedImage.TYPE_INT_RGB);
Graphics g = randomImage.getGraphics();
setBackground(g);
setBorder(g);
paintLine(g);
checkstring = setRandomString((Graphics2D) g);

g.dispose();
return randomImage;
}
//设置边框
private static void setBorder(Graphics g) {
g.setColor(Color.WHITE);
g.drawRect(1, 1, WIDTH - 2, HEIGHT - 2);
}
//随机数
private static String setRandomString(Graphics2D g) {
StringBuilder sb = new StringBuilder();
g.setFont(new Font("宋体", Font.BOLD, 22));
String randomString = "abcdefghijkmnpqrstuvwsyz23456789";
for (int i = 0; i < 4; i++) {
g.setColor(Color.red);
int x = 20 * i + 10;
String str = randomString.charAt(new Random().nextInt(randomString
.length())) + "";
sb.append(str);
int roll = new Random().nextInt() % 30;
g.rotate(roll * Math.PI / 180, x, 20);
g.drawString(str, x, 20);
g.rotate(-roll * Math.PI / 180, x, 20);
}
return sb.toString();
}
//画干扰线
private static void paintLine(Graphics g) {
g.setColor(Color.GREEN);
for (int i = 0; i < 5; i++) {
int x1 = new Random().nextInt(WIDTH);
int y1 = new Random().nextInt(HEIGHT);
int x2 = new Random().nextInt(WIDTH);
int y2 = new Random().nextInt(HEIGHT);
g.drawLine(x1, y1, x2, y2);
}
}
//设置背景颜色
private static void setBackground(Graphics g) {
// TODO Auto-generated method stub
g.setColor(Color.WHITE);
g.fillRect(0, 0, WIDTH, HEIGHT);
}

//将image验证码转化成字节数组输入流
private static ByteArrayInputStream convertImageToStream(BufferedImage image) {
ByteArrayInputStream inputStream = null;
ByteArrayOutputStream bos = new ByteArrayOutputStream();
JPEGImageEncoder jpeg = JPEGCodec.createJPEGEncoder(bos);
try {
jpeg.encode(image);
byte[] bts = bos.toByteArray();
inputStream = new ByteArrayInputStream(bts);
} catch (ImageFormatException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return inputStream;
}
}

//写一个Action类，用于接收请求，并且回送验证码图片
public class SecurityCodeImageAction extends ActionSupport implements
SessionAware {
private Map<String,Object> session;
private ByteArrayInputStream imageStream;

@Override
public String execute() throws Exception{

imageStream = SecurityCode.getImageAsInputStream();
String securityCode = SecurityCode.checkstring;
session.put("checkstring", securityCode);

return SUCCESS;
}

public ByteArrayInputStream getImageStream() {
return imageStream;
}

public void setImageStream(ByteArrayInputStream imageStream) {
this.imageStream = imageStream;
}

public Map<String, Object> getSession() {
return session;
}

@Override
public void setSession(Map<String, Object> session) {
// TODO Auto-generated method stub
this.session = session;
}

}

//最后配置Struts.xml文件即可
<!-- 验证码映射 -->
<action name ="SecurityCodeImageAction" class= "com.web.service.SecurityCodeImageAction">
<result name="success" type="stream">
<param name="contentType">image/jpeg</param>
<param name="inputName">imageStream</param>
<param name="bufferSize">2048</param>
</result>
</action>