ImageAction.java

package com.ytf.action;

import com.opensymphony.xwork2.ActionSupport;
import java.util.Random;
import java.awt.*;
import java.awt.image.*;
import java.io.ByteArrayOutputStream;
 
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.interceptor.SessionAware;
 
public class ImageAction extends ActionSupport {
    /**
     * ��֤���Ӧ��Session��
     */
    private static final String SessionName = "SESSION_SECURITY_CODE";
    /**
     * �������������֤�������Դ
     */
    private static final char[] source = new char[]{
       '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',
       '1', '2', '3', '4', '5', '6', '7', '8', '9', '0'
    };
    /**
     * ���������ӡ��֤����ַ���ɫ
     */
    private static final Color[] colors = new Color[]{
       Color.RED, Color.BLUE, Color.BLACK
    };
    /**
     * ���ڴ�ӡ��֤�������
     */
    private static final Font font = new Font("����", Font.BOLD, 13);
    /**
     * ��������������������������
     */
    private static final Random rdm = new Random();
   
    private String text = "";
   
    private byte[] bytes = null;
    private String contentType = "image/png";
   
    public byte[] getImageBytes(){
       return this.bytes;
    }
    public String getContentType(){
       return this.contentType;
    }
   
    public void setContentType(String value){
       this.contentType = value;
    }
   
    public int getContentLength(){
       return bytes.length;
    }
   
    /**
     * ���ɳ���Ϊ4������ַ���
     */
    private void generateText(){
       char[] source = new char[4];
       for(int i=0; i<source.length; i++){
           source[i] = ImageAction.source[rdm.nextInt(ImageAction.source.length)];
       }
       this.text = new String(source);
       // ����Session
       ServletActionContext.getRequest().getSession().setAttribute(SessionName, this.text);
    }
   
    /**
     * ���ڴ������ɴ�ӡ������ַ�����ͼƬ
     * @return ���ڴ��д����Ĵ�ӡ���ַ�����ͼƬ
     */
    private BufferedImage createImage(){
       int width = 50;
       int height = 20;
      
       BufferedImage image =
           new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
      
       Graphics g = image.getGraphics();
       //���ñ���ɫ
       g.setColor(Color.WHITE);
       //��䱳��
       g.fillRect(0, 0, width, height);
       //���ñ߿���ɫ
       g.setColor(Color.LIGHT_GRAY);
       //����������ʽ
       g.setFont(new Font("Arial",Font.BOLD,height-2));
       //���Ʊ߿�
       g.drawRect(0, 0, width - 1, height - 1);
       //�������
       Random rand = new Random();
       //���������ɫ
       g.setColor(Color.LIGHT_GRAY);
       for (int i = 0;i < 30;i++) {
    	   int x = rand.nextInt(width);
    	   int y = rand.nextInt(height);
    	   //����1 * 1��С�ľ���
    	   g.drawRect(x, y, 1, 1);
       }
       
       //������֤��
       g.setFont(font);
       for(int i=0; i<this.text.length(); i++){
           g.setColor(colors[rdm.nextInt(colors.length)]);
           g.drawString(this.text.substring(i, i+1), 8 + i * 8, 15);
       }
       g.dispose();
      
       return image;
    }
   
    /**
     * ����ͼƬ�����ֽ�����
     * @param image ���ڴ����ֽ������ͼƬ
     */
    private void generatorImageBytes(BufferedImage image){
       ByteArrayOutputStream bos = new ByteArrayOutputStream();
       try{
           javax.imageio.ImageIO.write(image, "jpg", bos);
           this.bytes = bos.toByteArray();
       }catch(Exception ex){
       }finally{
           try{
              bos.close();
           }catch(Exception ex1){
           }
       }
    }
 
    /**
     * ��struts2���������õķ���
     * @return ��Զ�����ַ���"image"
     */
    public String doDefault(){
      
       this.generateText();
       BufferedImage image = this.createImage();
       this.generatorImageBytes(image);
      
       return "image";
    }
}