package com.lee;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
//Servlet 3.0的 Annoation
/* @WebServlet 支持的常用属性
asyncSupported 否 指定该 Servlet 是否支持异步操作模式 .
displayname 否 指定 该servlet 的显示名称
initparams 否 为该servlet 配置参数
loadOnStartup 否 将该serlvet 配置成 load-on-startup类型的servlet
name 否 指定 该servlet的名称
urlPatterns/ value 否 这两个属性 的作用完全相同,都指定该Servlet 的 处理 URL
如果使用 Annotation
1:不需要在 web.xml 根元素 <web-app>中加入 metadata-complete="true".
2:不要在web.xml中配置该serlvet
Servlet 中的 不写 doGet 或者 doPost 可以统一交给 serlvet中 service方法处理.
*/
@WebServlet(name="ImageServlet",urlPatterns={"/ImageServlet"})
public class ImageServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
int width=80;
int height=30;
BufferedImage image=new BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR);
Graphics2D g=image.createGraphics();
//画背景 选取颜色,然后画大小
g.setColor(getRandColor(240,255)); //偏淡色
g.fillRect(0, 0, width, height);
//画边框
g.setColor(getRandColor(200,255));
g.fillRect(0, 0, width-1, height-1);
//画 干扰线 8条
g.setColor(getRandColor(100,255));
Random random=new Random();
for(int i=0;i<8;i++){ //两点确定一条直线,
int x1=random.nextInt(width);
int y1=random.nextInt(height);
int x2=random.nextInt(width);
int y2=random.nextInt(height);
g.drawLine(x1, y1, x2, y2);
}
//画 干扰 点
for(int i = 0;i<50;i++)
{
int x = random.nextInt(width);
int y = random.nextInt(height);
g.setColor(new Color(x+100,y+100,100));
g.drawOval(x, y, 1, 0);
}
Font font=new Font("Times New Roman",Font.ITALIC,24);
g.setFont(font);
int length=4;
int x = width / length; //字体间隔宽度
int codeY = height-font.getSize(); // 字体 高度
String s="qwertyuiopl0123456987kjhgfdsazxcvbnm0123456987QWERTYUIOPLKJH0123456987GFDSAZXCVBNM";
String code="";
for(int i=0;i<length;i++){
g.setColor(new Color(85+random.nextInt(110),85+random.nextInt(110),85+random.nextInt(110)));
String ch=String.valueOf(s.charAt(random.nextInt(s.length())));
code+=ch;
g.drawString(ch, i*x+5, font.getSize()+random.nextInt(codeY));
}
System.out.println(code);
//存储字符串到 session中
HttpSession session =req.getSession();
session.setAttribute("checkcode", code);
g.dispose();
resp.setHeader("Pragma", "No-cache");
resp.setHeader("Cache-Control", "No-cache");
resp.setDateHeader("Expires", 0);
resp.setContentType("image/jpeg");
//输出到流中
ServletOutputStream out=resp.getOutputStream();
ImageIO.write(image, "jpeg",out);
out.flush();
out.close();
}
public Color getRandColor(int lower,int upper){
Random random = new Random();
if(upper>255)
upper=255;
if(upper<1)
upper=1;
if(lower<1)
lower=1;
if(lower>255)
lower=255;
int r=lower+random.nextInt(upper-lower);
int g=lower+random.nextInt(upper-lower);
int b=lower+random.nextInt(upper-lower);
return new Color(r,g,b);
}
}
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" errorPage="system/error.jsp"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<%!
public int mcount;
%>
<script type="text/javascript" language="javascript">
function changeImg(){
var a=document.getElementById("mySpan");
a.innerHTML='<img align="middle" src="ImageServlet"/> <a href="#" onclick="changeImg();">看不清</a>';
}
</script>
<body>
<%-- <%@ include file="system/include.jsp"%> --%>
<jsp:include page="system/include.jsp"/>
使用 子页面中变量<br/>
<%
response.sendRedirect("anyScope.jsp");
%>
<span id="mySpan"><img align="middle" src="ImageServlet" />
<a href="#" onclick="changeImg();">看不清</a></span>
</body>
</html>
