Java代碼生成圖片驗證碼實現

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

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 < lineCount; 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 < codeCount; 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;

}
}  </pre> 


 在 servlet 中使用該類： 



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());

}
}  </pre> 


 在 web.xml配置Servlet訪問路徑： 

    <servlet>  
    <servlet-name>validateCodeServlet</servlet-name>  
    <servlet-class>com.rchm.util.images.ValidateCodeServlet</servlet-class>  
    </servlet>   
    <servlet-mapping>  
    <servlet-name>validateCodeServlet</servlet-name>  
    <url-pattern>code.images</url-pattern>