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Java代碼生成圖片驗證碼實現
編輯:JavaScript綜合知識     

   介紹一個使用Java代碼生成隨機圖片驗證碼的示例

  可以直接配置成Servlet,在頁面直接調用

  Java代碼隨機生成圖片驗證碼

  package com.rchm.util.images;

  import java.awt.Color;

  import java.awt.Font;

  import java.awt.Graphics2D;

  import java.awt.image.BufferedImage;

  import java.io.FileOutputStream;

  import java.io.IOException;

  import java.io.OutputStream;

  import java.util.Random;

  import javax.imageio.ImageIO;

  /**

  * 驗證碼生成器

  */

  public class ValidateCode {

  // 圖片的寬度。

  private int width = 160;

  // 圖片的高度。

  private int height = 40;

  // 驗證碼字符個數

  private int codeCount = 5;

  // 驗證碼干擾線數

  private int lineCount = 150;

  // 驗證碼

  private static String code = null;

  // 驗證碼圖片Buffer

  private BufferedImage buffImg=null;

  private char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J','K', 'L',

  'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W','X', 'Y',

  'Z', '1', '2', '3', '4', '5', '6', '7', '8', '9' };

  public ValidateCode() {

  this.createCode();

  }

  /**

  *

  * @param width 圖片寬

  * @param height 圖片高

  */

  public ValidateCode(int width,int height) {

  this.width=width;

  this.height=height;

  this.createCode();

  }

  /**

  *

  * @param width 圖片寬

  * @param height 圖片高

  * @param codeCount 字符個數

  * @param lineCount 干擾線條數

  */

  public ValidateCode(int width,int height,int codeCount,int lineCount) {

  this.width=width;

  this.height=height;

  this.codeCount=codeCount;

  this.lineCount=lineCount;

  this.createCode();

  }

  public void createCode() {

  int x = 0,fontHeight=0,codeY=0;

  int red = 0, green = 0, blue = 0;

  x = width / (codeCount +2);//每個字符的寬度

  fontHeight = height - 2;//字體的高度

  codeY = height - 4;

  // 圖像buffer

  buffImg = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);

  Graphics2D g = buffImg.createGraphics();

  // 生成隨機數

  Random random = new Random();

  // 將圖像填充為白色

  g.setColor(Color.WHITE);

  g.fillRect(0, 0, width, height);

  // 創建字體

  ImgFontByte imgFont=new ImgFontByte();

  Font font =imgFont.getFont(fontHeight);

  g.setFont(font);

  for (int i = 0; i

  int xs = random.nextInt(width);

  int ys = random.nextInt(height);

  int xe = xs+random.nextInt(width/8);

  int ye = ys+random.nextInt(height/8);

  red = random.nextInt(255);

  green = random.nextInt(255);

  blue = random.nextInt(255);

  g.setColor(new Color(red, green, blue));

  g.drawLine(xs, ys, xe, ye);

  }

  // randomCode記錄隨機產生的驗證碼

  StringBuffer randomCode = new StringBuffer();

  // 隨機產生codeCount個字符的驗證碼。

  for (int i = 0; i

  String strRand = String.valueOf(codeSequence[random.nextInt(codeSequence.length)]);

  // 產生隨機的顏色值,讓輸出的每個字符的顏色值都將不同。

  red = random.nextInt(255);

  green = random.nextInt(255);

  blue = random.nextInt(255);

  g.setColor(new Color(red, green, blue));

  g.drawString(strRand, (i + 1) * x, codeY);

  // 將產生的四個隨機數組合在一起。

  randomCode.append(strRand);

  }

  // 將四位數字的驗證碼保存到Session中。

  code = randomCode.toString();

  }

  public void write(String path) throws IOException {

  OutputStream sos = new FileOutputStream(path);

  this.write(sos);

  }

  public void write(OutputStream sos) throws IOException {

  ImageIO.write(buffImg, "png", sos);

  sos.close();

  }

  public BufferedImage getBuffImg() {

  return buffImg;

  }

  public static String getCode() {

  return code;

  }

  }

  在 servlet 中使用該類:

  package com.rchm.util.images;

  import java.io.IOException;

  import javax.servlet.ServletException;

  import javax.servlet.http.HttpServlet;

  import javax.servlet.http.HttpServletRequest;

  import javax.servlet.http.HttpServletResponse;

  import javax.servlet.http.HttpSession;

  public class ValidateCodeServlet extends HttpServlet {

  private static final long serialVersionUID = 1L;

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

  response.setContentType("image/jpeg");

  response.setHeader("Pragma", "no-cache");

  response.setHeader("Cache-Control", "no-cache");

  response.setDateHeader("Expires", 0);

  ValidateCode vCode = new ValidateCode(100,30,4,100);

  HttpSession session = request.getSession();

  session.removeAttribute("validateCode");

  vCode.write(response.getOutputStream());

  session.setAttribute("validateCode", vCode.getCode());

  vCode.write(response.getOutputStream());

  }

  }

  在 web.xml配置Servlet訪問路徑:

  validateCodeServlet

  class>com.rchm.util.images.ValidateCodeServletclass>

  validateCodeServlet

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