1.java類源碼package code;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
/**
* Created by Administrator on 2015/8/9.
* 驗證碼生成類
*/
public class IdentityServlet extends HttpServlet{
/**
* 隨機字符字典 去除阿拉伯數字 0，1；英文字母 O,I等難辨認的字符
*/
public static final char[] CHARS={'2','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','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();//隨機數
/**
* 獲取6位隨機數
* @return String
*/
public static String getRandomString(){
StringBuffer buffer = new StringBuffer();//字符緩存
for (int i=0;i<6;i++){
buffer.append(CHARS[random.nextInt(CHARS.length)]);//每次獲取一個隨機字符串
}
return buffer.toString();
}
/**
* 獲取隨機顏色
* @return
*/
public static Color getRandomColor() {
return new Color(random.nextInt(255),random.nextInt(255),random.nextInt(255));
}
/**
* 返回某個顏色的反色
* @param color
* @return
*/
public static Color getReverseColor(Color color){
return new Color(255 - color.getRed(),255 - color.getGreen(),255 - color.getBlue());
}
/**
* get請求方法
*/
public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
response.setContentType("UTF-8");
response.setContentType("image/jpeg");//設置輸出類型爲圖片
String randomString=getRandomString();//獲取隨機字符串
System.out.println("隨機字符串=" + randomString);
request.getSession(true).setAttribute("randomString",randomString);//放到Session中
int width=100;//圖片寬度
int height=30;//圖片高度
Color color=getRandomColor();//獲取隨機顏色
Color reverse=getReverseColor(color);//獲取反色
BufferedImage bufferedImage=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);//創建一個彩色圖片
Graphics2D graphics2D=bufferedImage.createGraphics();//獲取繪圖對象
graphics2D.setFont(new Font(Font.SANS_SERIF,Font.BOLD,16));//設置字體
graphics2D.setColor(color);//設置顏色
graphics2D.fillRect(0, 0, width, height);//繪製背景
graphics2D.setColor(reverse);//設置反色顏色
graphics2D.drawString(randomString,18,20);//
for (int i = 0; i < random.nextInt(100); i++) {//繪製干擾點
graphics2D.drawRect(random.nextInt(width),random.nextInt(height),1,1);//隨機干擾點
}
ServletOutputStream out=response.getOutputStream();
JPEGImageEncoder encoder= JPEGCodec.createJPEGEncoder(out);
encoder.encode(bufferedImage);
out.flush();
}
}
2.頁面調用 <pre name="code" class="html"><%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>圖片驗證碼</title>
</head>
<body>
<script>
function reloadImage(){
document.getElementById("btn").disabled=true;
document.getElementById("image_code").src="/code?ts="+new Date().getTime();
}
</script>
<img src="/code" id="image_code" onload="btn.disabled=false;">
<input type="button" id="btn" value="換個圖片" onclick="reloadImage()"/>
</body>
</html>3.web.xml配置
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
version="3.1">
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>piccode</servlet-name>
<servlet-class>code.IdentityServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>piccode</servlet-name>
<url-pattern>/code</url-pattern>
</servlet-mapping>
</web-app>4.顯示結果