java生成隨機驗證碼

A. J2EE中JSP頁面怎麼獲取java類里生成的隨機驗證碼

直接 <img src="your image request url" >

B. 用java隨機生成四位驗證碼，只求編程代碼

不知道你問的是不是生成這種圖片驗證碼？
如果只要一個隨機四位數 那這行代碼就夠了(new Random().nextInt(9000) + 1000;),
如果是生成頁面圖片驗證碼就是下面的了:
//設定 響應模式
resp.setContentType("image/jpeg");

// 生成令牌環數據;
Integer token = new Random().nextInt(9000) + 1000;

// 保存令牌環數據到session中
req.getSession().setAttribute(IMAGE_TOKEN_NAME, token);

// 生成令牌環圖片
ServletOutputStream out = resp.getOutputStream();
BufferedImage img = new BufferedImage(60, 20,
BufferedImage.TYPE_INT_RGB);
Graphics g = img.getGraphics();
g.setColor(Color.YELLOW);
g.fillRect(0, 0, img.getWidth(), img.getHeight());
g.setColor(Color.BLUE);
g.setFont(new Font("", Font.BOLD, 18));
g.drawString(String.valueOf(token), 10, 16);
ImageIO.write(img, "jpg", out);
out.close();

C. java swing隨機驗證碼

(HttpServletRequestrequest,
			HttpServletResponseresponse)throwsServletException,IOException{
			
			response.setContentType("image/jpeg");
			response.setHeader("Pragma","No-cache");
			response.setHeader("Cache-Control","no-cache");
			response.setDateHeader("Expires",0);
			HttpSessionsession=request.getSession();
			
			intwidth=60,height=20;
			
			BufferedImageimage=newBufferedImage(width,height,
			BufferedImage.TYPE_INT_RGB);
			
			//獲取圖形上下文
			Graphicsg=image.getGraphics();
			
			//生成隨機類
			Randomrandom=newRandom();
			
			//設定背景色
			g.setColor(getRandColor(200,250));
			g.fillRect(0,0,width,height);
			
			//設定字體
			g.setFont(newFont("TimesNewRoman",Font.PLAIN,18));
			
			//隨機產生155條干擾線，使圖象中的認證碼不易被其它程序探測到
			g.setColor(getRandColor(160,200));
			for(inti=0;i<155;i++){
			intx=random.nextInt(width);
			inty=random.nextInt(height);
			intxl=random.nextInt(12);
			intyl=random.nextInt(12);
			g.drawLine(x,y,x+xl,y+yl);
			}
			
			//取隨機產生的認證碼(4位數字)
			StringsRand="";
			for(inti=0;i<4;i++){
			Stringrand=String.valueOf(random.nextInt(10));
			sRand+=rand;
			//將認證碼顯示到圖象中
			g.setColor(newColor(20+random.nextInt(110),20+random
			.nextInt(110),20+random.nextInt(110)));//調用函數出來的顏色相同，可能是因為種子太接近，所以只能直接生成
			g.drawString(rand,13*i+6,16);
			}
			
			//將認證碼存入SESSION
			session.setAttribute("rand",sRand);
			//圖象生效
			g.dispose();
			=response.getOutputStream();
			//輸出圖象到頁面
			ImageIO.write(image,"JPEG",responseOutputStream);
			
			//以下關閉輸入流！
			responseOutputStream.flush();
			responseOutputStream.close();
			}
			
		static	ColorgetRandColor(intfc,intbc){
			//給定范圍獲得隨機顏色
			Randomrandom=newRandom();
			if(fc>255)
			fc=255;
			if(bc>255)
			bc=255;
			intr=fc+random.nextInt(bc-fc);
			intg=fc+random.nextInt(bc-fc);
			intb=fc+random.nextInt(bc-fc);
			returnnewColor(r,g,b);
			}
			
			/**
			*HandlestheHTTPGETmethod.
			*
			*@paramrequest
			*servletrequest
			*@paramresponse
			*servletresponse
			*/
			protectedvoiddoGet(HttpServletRequestrequest,
			HttpServletResponseresponse)throwsServletException,IOException{
			processRequest(request,response);
			}

這個是我web里用的驗證碼，你可以改改

D. Java上機怎麼隨機生成驗證碼

我在網上看過PHP做的一個隨機字元串生成程序，很簡單的喔，親：
function randStr($length=8)
{
$str = substr(md5(time()), 0, $length);
return $str;
}
具體步驟就是先獲得當前時間毫秒數，再md5加密後取前多少位就行了。

E. Java Swing中隨機驗證碼如何實現

根本思想是使用
隨機數
具體實現：
1.
生成一個隨機數
2.
將隨機數使用全局變數保留
3.
將隨機數設置成按鈕的提示文字
4.
編寫點擊之後重新生成隨機數，並且綁定到按鈕上
5.
驗證
如果需要實例，請留下郵箱！^_^

F. Java產生隨機驗證碼

package com.you100.util;
import java.util.Random;
public class Picture {
public static void main(String[] args) {
Random ran=new Random();char ch[] =new char[]{'a','b','c','d','e','f','g','@','1','2','3','4','5'};

StringBuilder str=new StringBuilder("");
for(int i=0;i<4;i++){

str.append(ch[ran.nextInt(ch.length)]);

}
System.out.println("驗證碼="+str);

}}

在控制台上隨回機生成答驗證碼

G. 如何在java中生成驗證碼在頁面生成

以下是我寫的生成的圖片驗證碼

//調用驗證碼生成並把驗證碼返回頁面
Map<String,BufferedImage>imageMap=ImageUtil.createImage();
		Stringcode=imageMap.keySet().iterator().next();
		session.setAttribute("imageCode",code);
		BufferedImageimage=imageMap.get(code);
		response.setContentType("image/jpeg");
		OutputStreamops=response.getOutputStream();
		ImageIO.write(image,"jpeg",ops);
		ops.close();

//生成驗證碼工具類
publicfinalclassImageUtil{
	
	privatestaticfinalchar[]chars={'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','0','1','2','3','4','5','6','7','8','9'};
	privatestaticfinalintSIZE=4;
	privatestaticfinalintLINES=5;
	privatestaticfinalintWIDTH=80;
	privatestaticfinalintHEIGHT=40;
	privatestaticfinalintFONT_SIZE=30;

	publicstaticMap<String,BufferedImage>createImage(){
		StringBuffersb=newStringBuffer();
		BufferedImageimage=newBufferedImage(WIDTH,HEIGHT,
				BufferedImage.TYPE_INT_RGB);
		Graphicsgraphic=image.getGraphics();
		graphic.setColor(Color.LIGHT_GRAY);
		graphic.fillRect(0,0,WIDTH,HEIGHT);
		Randomran=newRandom();
		//畫隨機字元
		for(inti=1;i<=SIZE;i++){
			intr=ran.nextInt(chars.length);
			graphic.setColor(getRandomColor());
			graphic.setFont(newFont(null,Font.BOLD+Font.ITALIC,FONT_SIZE));
			graphic.drawString(chars[r]+"",(i-1)*WIDTH/SIZE,HEIGHT/2);
			sb.append(chars[r]);
		}
		//畫干擾線
		for(inti=1;i<=LINES;i++){
			graphic.setColor(getRandomColor());
			graphic.drawLine(ran.nextInt(WIDTH),ran.nextInt(HEIGHT),
					ran.nextInt(WIDTH),ran.nextInt(HEIGHT));
		}
		Map<String,BufferedImage>map=newHashMap<String,BufferedImage>();
		map.put(sb.toString(),image);
		returnmap;
	}

	(){
		Randomran=newRandom();
		Colorcolor=newColor(ran.nextInt(256),ran.nextInt(256),ran.nextInt(256));
		returncolor;
	}

	(BufferedImageimage)
			throwsIOException{
		ByteArrayOutputStreambos=newByteArrayOutputStream();
		JPEGImageEncoderencoder=JPEGCodec.createJPEGEncoder(bos);
		encoder.encode(image);
		byte[]imageBts=bos.toByteArray();
		InputStreamin=newByteArrayInputStream(imageBts);
		returnin;
	}
}

H. JAVA程序中，隨機產生一個6位的驗證碼 (是由0

import java.util.Random;

public class TestRandom {
public String getRandStr(int charCount) {
String charValue = "";
for (int i = 0; i < charCount; i++){
char c = (char) (randomInt(0,26)+'a');
charValue += String.valueOf(c);
}
return charValue;
}
public String getRandNum(int charCount) {
String charValue = "";
for (int i = 0; i < charCount; i++){
char c = (char) (randomInt(0,10)+'0');
charValue += String.valueOf(c);
}
return charValue;
}

public int randomInt(int from, int to){
Random r = new Random();
return from + r.nextInt(to - from);
}
}

I. 用java實現：隨機獲取4位的驗證碼

驗證碼是指網頁的驗證碼還是手機的驗證碼

下面是隨機生成四位數的相關代碼

importjava.util.Random;

publicclassRandomTest{
publicstaticvoidmain(String[]args){
System.out.println("Math.random得到小數");
System.out.println(Math.round(Math.random()*10000));
System.out.println("Random");
System.out.println(newRandom().nextInt(9999));
System.out.println("字元串前面補0的話就這樣String.format");
System.out.println(String.format("%04d",newRandom().nextInt(9999)));
}
}