Java生成驗證碼的代碼

package com.web;
//驗證碼生成處理類
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.geom.Line2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import com.tools.MD5;
public class PictureCheckCode extends HttpServlet{

private static final long serialVersionUID = 1L;

private Random rand=new Random();


/**
 * 生成隨機顏色
 * 
 * @param   start  [int]
 * @param   end    [int]
 * @return  Color  [object]
 */
public Color getRandColor(int start,int end){
    int randNum;
    if(start>255) start=255;
    if(end>255) end=255;
    if(start>end) randNum=start-end;
    else randNum=end-start;
    int r=start+rand.nextInt(randNum);
    int g=start+rand.nextInt(randNum);
    int b=start+rand.nextInt(randNum);
    return new Color(r,g,b);
}


/**
 * 著色\旋轉\縮放
 * 
 * @param word 文字
 * @param g    圖片對象
 */
public void coloredAndRotation(String word,int i,Graphics g){
    /**著色**/
    g.setColor(new Color(20+rand.nextInt(110),20+rand.nextInt(110),20+rand.nextInt(110)));
    /**旋轉**/
    Graphics2D g2d=(Graphics2D)g;
    AffineTransform trans=new AffineTransform();
    trans.rotate(rand.nextInt(45)*3.14/180,15*i+8,7);
    /**縮放**/
    float scaleSize=rand.nextFloat()+0.8f;
    if(scaleSize>1f) scaleSize=1f;
    trans.scale(scaleSize, scaleSize);
    g2d.setTransform(trans);
    g.drawString(word,15*i+20,20);
}

/**
 * 生成100條干擾線
 * 
 * @param g2d
 * @param width
 * @param height
 */
public void getRandLine(Graphics2D g2d,int width,int height){
    for(int i=0;i<100;i++){
        int x=rand.nextInt(width-1);
        int y=rand.nextInt(height-1);
        int z=rand.nextInt(6)+1;
        int w=rand.nextInt(12)+1;

        BasicStroke bs=new BasicStroke(2f,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
        Line2D line=new Line2D.Double(x,y,x+z,y+w);
        g2d.setStroke(bs);
        g2d.draw(line);
    }
}

/**
 * 獲取隨機文字
 * 
 * @param  length [int]        驗證碼長度
 * @param  g      [Graphics]   圖片對象
 * @return String
 * @case1:A-Z
 * @case2:chinese
 * @default:0-9
 */
@SuppressWarnings("unused")
public String getRandWord(int length,Graphics g){
    String finalWord="",firstWord="";
    int tempInt=0;
    String[] array={
            "0","1","2","3",
            "4","5","6","7",
            "8","9","a","b",
            "c","d","e","f"};

    for(int i=0;i<length;i++){
        switch(rand.nextInt(2)){
            case 1:
                    tempInt=rand.nextInt(26)+65;
                    firstWord=String.valueOf((char)tempInt);
                    break;
            /*case 2:
                    int r1,r2,r3,r4;
                    String strH,strL;//high&low
                    r1=rand.nextInt(3)+11; //前閉后開[11,14)
                    if(r1==13){
                        r2=rand.nextInt(7);
                    }else{
                        r2=rand.nextInt(16);
                    }

                    r3=rand.nextInt(6)+10;
                    if(r3==10){
                        r4=rand.nextInt(15)+1;
                    }else if(r3==15){
                        r4=rand.nextInt(15);
                    }else{
                        r4=rand.nextInt(16);
                    }

                    strH=array[r1]+array[r2];
                    strL=array[r3]+array[r4];

                    byte[] bytes=new byte[2];
                    bytes[0]=(byte)(Integer.parseInt(strH,16));
                    bytes[1]=(byte)(Integer.parseInt(strL,16));

                    firstWord=new String(bytes);
                    break;*/
            default:
                    tempInt=rand.nextInt(10)+48;
                    firstWord=String.valueOf((char)tempInt);
                    break;
        }
        finalWord+=firstWord;
        this.coloredAndRotation(firstWord,i, g);
    }

    return finalWord;
}

protected void service(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {

    //設制不緩存圖片
    response.setHeader("Pragma","No-cache");
    response.setHeader("Cache-Control","No-cache");
    response.setDateHeader("Expires",0);

    //生成圖片
    response.setContentType("image/jpeg");
    int width=100;
    int height=40;
    BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

    Graphics g=image.getGraphics();
    Graphics2D g2d=(Graphics2D)g;
    Font mFont=new Font("宋體",Font.BOLD,22);
    g.setColor(this.getRandColor(200,250));
    g.fillRect(0, 0, width, height);
    g.setFont(mFont);
    g.setColor(this.getRandColor(180,200));

    this.getRandLine(g2d, width, height);

    String randCode=this.getRandWord(4, g);

    HttpSession session=request.getSession();
    session.setAttribute("randCode",MD5.code(randCode.toLowerCase()));

    g.dispose();

    ImageIO.write(image,"JPEG",response.getOutputStream());

}


}
</pre>