Java 生成網頁驗證碼幾種方式

原創 小布丁智囊 2018-09-04 09:34

1，在jsp頁面中直接生成驗證碼

//image.jsp
<%@ page contentType="image/jpeg"
	import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*"
	pageEncoding="GBK"%>
<%!Color getRandColor(int fc, int bc) {//給定範圍獲得隨機顏色
		Random random = new Random();
		if (fc > 255)
			fc = 255;
		if (bc > 255)
			bc = 255;
		int r = fc + random.nextInt(bc - fc);
		int g = fc + random.nextInt(bc - fc);
		int b = fc + random.nextInt(bc - fc);
		return new Color(r, g, b);
	}%>
<%
	//設置頁面不緩存
	response.setHeader("Pragma", "No-cache");
	response.setHeader("Cache-Control", "no-cache");
	response.setDateHeader("Expires", 0);

	// 在內存中創建圖象
	// 通過這裏可以修改圖片大小
	int width = 85, height = 23;
	BufferedImage image = new BufferedImage(width, height,
			BufferedImage.TYPE_INT_RGB);

	// 獲取圖形上下文
	// g相當於筆
	Graphics g = image.getGraphics();

	//生成隨機類
	Random random = new Random();

	// 設定背景色
	g.setColor(getRandColor(200, 250));
	// 畫一個實心的長方，作爲北京
	g.fillRect(0, 0, width, height);

	//設定字體
	g.setFont(new Font("黑體", Font.PLAIN, 18));

	//畫邊框
	g.setColor(Color.BLUE);
	g.drawRect(0,0,width-1,height-1);

	// 隨機產生155條幹擾線，使圖象中的認證碼不易被其它程序探測到
	g.setColor(getRandColor(160, 200));
	for (int i = 0; i < 155; i++) {
		int x = random.nextInt(width);
		int y = random.nextInt(height);
		int xl = random.nextInt(12);
		int yl = random.nextInt(12);
		g.drawLine(x, y, x + xl, y + yl);
	}

	// 取隨機產生的認證碼(4位數字)
	//String rand = request.getParameter("rand");
	//rand = rand.substring(0,rand.indexOf("."));
	String sRand = "";
	// 如果要使用中文，必須定義字庫，可以使用數組進行定義
	// 這裏直接寫中文會出亂碼，必須將中文轉換爲unicode編碼
	String[] str = { "A", "B", "C", "D", "E", "F", "G", "H", "J", "K",
			"L", "M", "N", "P", "Q", "R", "S", "T", "U", "V", "W", "X",
			"Y", "Z", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j",
			"k", "m", "n", "p", "s", "t", "u", "v", "w", "x", "y", "z",
			"1", "2", "3", "4", "5", "6", "7", "8", "9" };

	for (int i = 0; i < 5; i++) {
		String rand = str[random.nextInt(str.length)];
		sRand += rand;
		// 將認證碼顯示到圖象中
		g.setColor(new Color(20 + random.nextInt(110), 20 + random
				.nextInt(110), 20 + random.nextInt(110)));//調用函數出來的顏色相同，可能是因爲種子太接近，所以只能直接生成
		g.drawString(rand, 16 * i + 6, 19);
	}

	// 將認證碼存入SESSION
	session.setAttribute("rand", sRand);

	// 圖象生效
	g.dispose();

	// 輸出圖象到頁面
	ImageIO.write(image, "JPEG", response.getOutputStream());
	out.clear();
	out = pageContext.pushBody();
%>

 

//使用驗證碼的頁面login.jsp
<%@ page contentType="text/html" pageEncoding="GBK"%>
<html>
	<head>
		<title>登陸頁面</title>
		<script>
	function reloadImage() { 
		document.getElementById('identity').src = 'image.jsp?ts=' + new Date()
				.getTime();
	}
</script>
	</head>
	<body>
		<center>
			<%
				// 亂碼解決
				request.setCharacterEncoding("GBK");
			%>
			<h1>
				登陸程序
			</h1>
			<hr>
			<%=request.getAttribute("info") != null ? request
					.getAttribute("info") : ""%>
			<form action="check.jsp" method="post">
				用戶ID：
				<input type="text" name="mid">
				<br>
				密  碼：
				<input type="password" name="password">
				<br>
				驗證碼：
				<input type="text" name="code"  maxlength="5" size="5">
				<img src="image.jsp" id="identity" onclick="reloadImage()" title="看不清，點擊換一張">
				<br>
				<input type="submit" value="登陸">
				<input type="reset" value="重置">
			</form>
		</center>
	</body>
</html>

效果如下：



2，使用Servlet生成驗證碼

//IdentityServlet.java代碼如下：
package com.helloweenvsfei.servlet;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class IdentityServlet extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = -479885884254942306L;

	public static final char[] CHARS = { '2', '3', '4', '5', '6', '7', '8',
			'9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M',
			'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };

	public static Random random = new Random();

	public static String getRandomString() {
		StringBuffer buffer = new StringBuffer();
		for (int i = 0; i < 6; i++) {
			buffer.append(CHARS[random.nextInt(CHARS.length)]);
		}
		return buffer.toString();
	}

	public static Color getRandomColor() {
		return new Color(random.nextInt(255), random.nextInt(255), random
				.nextInt(255));
	}

	public static Color getReverseColor(Color c) {
		return new Color(255 - c.getRed(), 255 - c.getGreen(), 255 - c
				.getBlue());
	}

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

		response.setContentType("image/jpeg");

		String randomString = getRandomString();
		request.getSession(true).setAttribute("randomString", randomString);

		int width = 100;
		int height = 30;

		Color color = getRandomColor();
		Color reverse = getReverseColor(color);

		BufferedImage bi = new BufferedImage(width, height,
				BufferedImage.TYPE_INT_RGB);
		Graphics2D g = bi.createGraphics();
		g.setFont(new Font(Font.SANS_SERIF, Font.BOLD, 16));
		g.setColor(color);
		g.fillRect(0, 0, width, height);
		g.setColor(reverse);
		g.drawString(randomString, 18, 20);
		for (int i = 0, n = random.nextInt(100); i < n; i++) {
			g.drawRect(random.nextInt(width), random.nextInt(height), 1, 1);
		}

		// 轉成JPEG格式
		ServletOutputStream out = response.getOutputStream();
		JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
		encoder.encode(bi);
		out.flush();
	}

	public static void main(String[] args) {
		System.out.println(getRandomString());
	}
}
//Web.xml的配置爲：
<servlet>
    <servlet-name>IdentityServlet</servlet-name>
    <servlet-class>com.helloweenvsfei.servlet.IdentityServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>IdentityServlet</servlet-name>
    <url-pattern>/servlet/IdentityServlet</url-pattern>
</servlet-mapping>

//測試頁面identity.html爲：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
	<head>
		<title>identity.html</title>

		<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
		<meta http-equiv="description" content="this is my page">
		<meta http-equiv="content-type" content="text/html; charset=GB18030">

		<!--<link rel="stylesheet" type="text/css" href="./styles.css">-->

	</head>

	<body>

<script>
	function reloadImage() {
		document.getElementById('btn').disabled = true;
		document.getElementById('identity').src='servlet/IdentityServlet?ts=' + new Date().getTime();
	}
	</script>

		<img src="servlet/IdentityServlet" id="identity" onload="btn.disabled = false; " />
		<input type=button value=" 換個圖片 " onclick="reloadImage()" id="btn">

	</body>
</html>

3，在Struts2應用中生成驗證碼

//RandomNumUtil.java
package org.ml.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.imageio.stream.ImageOutputStream;

public class RandomNumUtil {
	public static final char[] CHARS = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M',
		'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z','2', '3', '4', '5', '6', '7', '8',
		'9','a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm',
		'n', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'}; 
	private ByteArrayInputStream image;// 圖像
	private String str;// 驗證碼
	/**
	 *  構造方法調用初始化屬性方法
	 */
	private RandomNumUtil() {
		init();
	}

	/**
	 * 取得RandomNumUtil實例
	 */
	public static RandomNumUtil Instance() {
		return new RandomNumUtil();
	}

	/**
	 * 取得驗證碼圖片
	 */
	public ByteArrayInputStream getImage() {
		return this.image;
	}

	/**
	 * 取得圖片的驗證碼
	 */
	public String getString() {
		return this.str;
	}
	
	/**
	 * 初始化屬性否具體方法
	 */
	private void init() {
		// 在內存中創建圖象
		int width = 85, height = 18;
		//設置圖形的高度和寬度，以及RGB類型
		BufferedImage image = new BufferedImage(width, height,
				BufferedImage.TYPE_INT_RGB);
		// 獲取圖形上下文
		Graphics g = image.getGraphics();
		// 生成隨機類
		Random random = new Random();
		// 設定背景色
		g.setColor(getRandColor(200, 250));
		g.fillRect(0, 0, width, height);
		// 設定字體
		g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
		// 隨機產生255條幹擾線，使圖象中的認證碼不易被其它程序探測到
		g.setColor(getRandColor(160, 200));
		for (int i = 0; i < 255; i++) {
			int x = random.nextInt(width);
			int y = random.nextInt(height);
			int xl = random.nextInt(12);
			int yl = random.nextInt(12);
			g.drawLine(x, y, x + xl, y + yl);
		}
		// 取隨機產生的認證碼(6位數字)
		StringBuffer sRand = new StringBuffer();  
		for (int i = 0; i < 6; i++) {
			String rand = String.valueOf(CHARS[random.nextInt(CHARS.length-1)]);//從字符數組中隨機產生一個字符
			sRand.append(rand); 
			// 將認證碼顯示到圖象中
			g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
			// 調用函數出來的顏色相同，可能是因爲種子太接近，所以只能直接生成
			g.drawString(rand, 13 * i + 6, 17);
		}
		// 賦值驗證碼
		this.str = sRand.toString();

		// 圖象生效
		g.dispose();
		//下面將生成的圖形轉變爲圖片
		ByteArrayOutputStream output = new ByteArrayOutputStream(); 
		ByteArrayInputStream input = null;
		try {
			ImageOutputStream imageOut = ImageIO.createImageOutputStream(output);
			ImageIO.write(image, "JPEG", imageOut);//將圖像按JPEG格式寫入到imageOut中，即存入到output的字節流中
			imageOut.close();//關閉寫入流
			input = new ByteArrayInputStream(output.toByteArray());//input讀取output中的圖像信息
		} catch (Exception e) {
			System.out.println("驗證碼圖片產生出現錯誤：" + e.toString());
		}

		this.image = input;/* 賦值圖像 */
	} 
	/*
	 * 給定範圍獲得隨機顏色
	 */
	private Color getRandColor(int fc, int bc) {
		Random random = new Random();
		if (fc > 255)
			fc = 255;
		if (bc > 255)
			bc = 255;
		int r = fc + random.nextInt(bc - fc);
		int g = fc + random.nextInt(bc - fc);
		int b = fc + random.nextInt(bc - fc);
		return new Color(r, g, b);
	}
}

//RandomAction.java的代碼：
package org.ml.action;

import java.io.ByteArrayInputStream;

import org.ml.util.RandomNumUtil;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

@SuppressWarnings("serial")
public class RandomAction extends ActionSupport {
	private ByteArrayInputStream inputStream;

	public String execute() throws Exception {
		RandomNumUtil rdnu = RandomNumUtil.Instance();//取得隨機驗證碼產生類的對象
		this.setInputStream(rdnu.getImage());// 取得帶有隨機字符串的圖片
		ActionContext.getContext().getSession().put("random", rdnu.getString());// 取得隨機字符串放入HttpSession
		return SUCCESS;
	}

	public void setInputStream(ByteArrayInputStream inputStream) {
		this.inputStream = inputStream;
	}

	public ByteArrayInputStream getInputStream() {
		return inputStream;
	}
}
//struts.xml配置爲：
<!-- Random驗證碼 -->
<action name="rand" class="org.ml.action.RandomAction">
    <result type="stream" name="success">
	<param name="contentType">image/JPEG</param>
	<param name="inputName">inputStream</param>
    </result>
</action>
//HTML中的表單代碼爲：
<tr  height="35" >
 <td width="14%" class="top_hui_text">
  <span class="login_txt"> 驗證碼：    </span>
 </td>
 <td colspan="2" class="top_hui_text">
  <input type="text" name="rand" id="rand" size="6"
   maxlength="6">
     <script type="text/javascript"> 
  function changeValidateCode(obj) { 
  //獲取當前的時間作爲參數，無具體意義 
   var timenow = new Date().getTime(); 
  //每次請求需要一個不同的參數，否則可能會返回同樣的驗證碼 
  //這和瀏覽器的緩存機制有關係，也可以把頁面設置爲不緩存，這樣就不用這個參數了。 
   obj.src="rand.action?d="+timenow; 
  } 
  </script>
  <img src="rand.action" title="點擊圖片刷新驗證碼"
   onclick="changeValidateCode(this)" height="22"
   width="80" />
 </td> 
</tr>











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