Java动态验证码单线设计的两种方法

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
 * Servlet implementation class inde
 */
@WebServlet("/inde")
public class inde extends HttpServlet {
  private static final long serialVersionUID = 1L;
  /**
   * @see HttpServlet#HttpServlet()
   */
  public inde() {
    super();
    // TODO Auto-generated constructor stub
  }
  /**
   * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
   */
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      this.doPost(request, response);      
  }
  /**动态生成图片验证码
   * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
   */
  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    //创建图像
    int width=100;
    int height=40;
    //图片的大小设置
    BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
    //创建画板    
    Graphics g=image.getGraphics();  
     setSquareBackGround(g,width,height,5);
    //确定画笔颜色
    g.setColor(Color.black);
    //填充矩形
    g.fillRect(0, 0, width, height);
      //在大矩形中放小矩形
      g.setColor(Color.WHITE);
      g.fillRect(1, 1, width-2, height-2);        
    //填充字符
    String str = "qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM0123456789";
    StringBuffer sb=new StringBuffer();
     //画随机干扰框
    setSquareBackGround(g,width,height,3); 
    //画干扰点
    CreateRandomPoint(width, height,100,g,100);    
    //随机画几条线
    CreateRandomLine(width, height,8,g,100);  
    //随机获取4个字符
    Random random=new Random();
    for (int i = 0; i < 4; i++) {
      //62个填充字符里面随机的随机的收取字符
      int index=random.nextInt(62);
      //截取一个字符
      String st=str.substring(index, index+1);
      //把字符放到图片中去
      g.setColor(Color.red);
      //设置字体
      g.setFont(new Font("宋体",Font.BOLD,30));
      g.drawString(st, 20*i, 30);//防止4个字符在一起
      sb.append(st);
    }
    //把StringBuffer中的验证码放到session里面，目的是让Login调用
    HttpSession se=request.getSession();
    se.setAttribute("number", sb.toString());
    //发送图片到浏览器 指定发送的图片 和格式
    response.setContentType("image/jpeg");
    //图片，图片的格式，输出的方式
    ImageIO.write(image, "jpg", response.getOutputStream());
  }
  Random rand = new Random();
  private void CreateRandomPoint(int width,int height,int many,Graphics g,int alpha)
  { // 随机产生干扰点
    for (int i=0;i<many;i++) {
      int x = rand.nextInt(width); 
      int y = rand.nextInt(height); 
      g.setColor(getColor(alpha));
      g.drawOval(x,y,rand.nextInt(3),rand.nextInt(3)); 
    } 
  }
/**
 * 随机产生干扰线条
 * @param width
 * @param height
 * @param minMany 最少产生的数量
 * @param g
 * @param alpha 透明度0~255 0表示全透
 */
  private void CreateRandomLine(int width,int height,int minMany,Graphics g,int alpha)
  { // 随机产生干扰线条
    for (int i=0;i<getIntRandom(minMany, minMany+6);i++) { 
      int x1 =getIntRandom(0,(int)(width*0.6)); 
      int y1 =getIntRandom(0,(int)(height*0.6)); 
      int x2 =getIntRandom((int)(width*0.4),width); 
      int y2 =getIntRandom((int)(height*0.2),height); 
      g.setColor(getColor(alpha));
      g.drawLine(x1, y1, x2, y2);
    } 
  }
  /**
   * 由随机产生的方块来作为干扰背景
   */
  private void setSquareBackGround(Graphics g,int width,int height,int count){
    // 随机产生干扰线条
    for (int i=0;i<getIntRandom(count, count+2);i++) { 
      int x1 =getIntRandom(0,(int)(width*0.3)); 
      int y1 =getIntRandom(0,(int)(height*0.3)); 
      int x2 =getIntRandom((int)(width*0.5),width); 
      int y2 =getIntRandom((int)(height*0.55),height); 
      g.setColor(getColor(100));
      int w=x2-x1;
      int h=y2-y1;
      if(w<0) w=-w;
      if(h<0) h=-h;
      g.drawRect(x1, y1, w, h);
      g.setColor(getColor(25));
      g.fillRect(x1, y1, w, h);
    } 
  }
  private int getIntRandom(double start,double end)
  {  if(end<start)
    {
     double t=end;
     end=start;
     start=t;
    }
    double i=start+(int) (Math.random()*(end-start));
    return (int)i;
  }

import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
 * Servlet implementation class inde
 */
@WebServlet("/inde")
public class inde extends HttpServlet {
  private static final long serialVersionUID = 1L;
  /**
   * @see HttpServlet#HttpServlet()
   */
  public inde() {
    super();
    // TODO Auto-generated constructor stub
  }
  /**
   * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
   */
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      this.doPost(request, response);      
  }
  /**动态生成图片验证码
   * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
   */
  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    //创建图像
    int width=100;
    int height=40;
    //图片的大小设置
    BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
    //创建画板    
    Graphics g=image.getGraphics();  
     setSquareBackGround(g,width,height,5);
    //确定画笔颜色
    g.setColor(Color.black);
    //填充矩形
    g.fillRect(0, 0, width, height);
      //在大矩形中放小矩形
      g.setColor(Color.WHITE);
      g.fillRect(1, 1, width-2, height-2);        
    //填充字符
    String str = "qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM0123456789";
    StringBuffer sb=new StringBuffer();
//随机获取4个字符
    Random random=new Random();
    for (int i = 0; i < 4; i++) {
      //62个填充字符里面随机的随机的收取字符
      int index=random.nextInt(62);
      //截取一个字符
      String st=str.substring(index, index+1);
      //把字符放到图片中去
      g.setColor(Color.red);
      //设置字体
      g.setFont(new Font("宋体",Font.BOLD,30));
      g.drawString(st, 20*i, 30);//防止4个字符在一起
      sb.append(st);
    }
//把StringBuffer中的验证码放到session里面，目的是让Login调用
    HttpSession se=request.getSession();
    se.setAttribute("number", sb.toString());
    //发送图片到浏览器 指定发送的图片 和格式
    response.setContentType("image/jpeg");
    //图片，图片的格式，输出的方式
    ImageIO.write(image, "jpg", response.getOutputStream());
  }