JavaWeb: Servlet生成驗證碼
阿新 • • 發佈:2019-02-14
package cn.itcast;
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
public class VCode {
private int w=70;
private int h=35;
private Color bgColor = new Color(240,240,240);
private Random random = new Random();
private StringBuilder code = new StringBuilder(4);
//使用者呼叫這個方法獲取圖片
public BufferedImage getImage(){
/*
* 我們要寫字元
* 寫什麼字元,-->隨機生成字元,範圍0-9,a-z,A-Z
* 字型::字號::是否粗體::-->全都隨機
* 字元顏色-->都隨機
*/
BufferedImage img = createImage();
Graphics g = img.getGraphics();
//畫東西
for(int i=0;i<4;i++){
String ch = this.randomChar();//獲取隨機字元
code.append(ch);
g.setColor(this.randomColor());//隨機顏色
g.setFont(this.randomFont());//隨機字型
g.drawString(ch, w/4*i, h-5); //寫字
}
this.drawLine(img); //畫干擾線
return img;
}
//這個方法必須在getImage()方法之後呼叫!
public String getCode(){
return code.toString();
}
private Color randomColor(){
int r = random.nextInt(256);
int g = random.nextInt(256);
int b = random.nextInt(256);
return new Color(r,g,b);
}
/*
* 隨機生成字元
*/
private String codes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
private String randomChar(){
int index = random.nextInt(codes.length());
return codes.charAt(index)+"";
}
/*
* 字型名 樣式 大小
*/
private String[] fontName = {"宋體","華文楷體","黑體","華文新魏","華文隸書","微軟雅黑","楷體"};
private int[] fontSize = {24,25,26,27,28};//字號範圍
private Font randomFont(){
int index =random.nextInt(fontName.length);//若陣列長度為7,則生成數值為0-6
String name = fontName[index];
int style = random.nextInt(4);
index = random.nextInt(fontSize.length);
int size= fontSize[index];
return new Font(name,style,size);
}
private BufferedImage createImage() {
/*
* 1.建立圖片
* 2.設定背景色
*/
BufferedImage img = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
//設定畫筆顏色
img.getGraphics().setColor(bgColor);
//直充一個與圖片大小一樣的矩形,即設定背景色
img.getGraphics().fillRect(0, 0, w, h);
return img;
}
private void drawLine(BufferedImage img){
Graphics2D g = (Graphics2D)img.getGraphics();
g.setColor(Color.BLACK);
g.setStroke(new BasicStroke(1.5F));
for(int i=0;i<5;i++){
int x1=random.nextInt(w);
int y1=random.nextInt(h);
int x2=random.nextInt(w);
int y2=random.nextInt(h);
g.drawLine(x1, y1, x2, y2);
}
}
public static void saveImage(BufferedImage img,OutputStream out) throws IOException{
ImageIO.write(img, "jpeg", out);
}
}
package cn.itcast;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class BServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
VCode vc = new VCode();
BufferedImage img = vc.getImage();
System.out.println(vc.getCode());
VCode.saveImage(img, response.getOutputStream());
}
}
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
This is my JSP page. <br>
驗證碼:<input type="text" name="vcode" size = "3"/> <br/>
<img id="vc" src="/verifyCodeTest/BServlet" border="2"/>
<a href='javascript:_change()'>看不清換一張</a>
<script type="text/javascript">
function _change(){
var img =document.getElementById("vc");
img.src="/verifyCodeTest/BServlet?a="+new Date().getTime();
}
</script>
<br/>
<input type="submit" value="提交">
</body>
</html>