java
package com;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ValidateCode
extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L
;
private static final int I_WIDTH = 60;
// 图片宽度
private static final int I_HEIGHT = 18;
// 图片高度
private static Font VALIDATECODE_FONT =
new Font("Times New Roman", 0, 18);
// 字体
private static String codeName =
null;
// 保存到session里面的名字
public ValidateCode() {
super();
}
public void destroy() {
super.destroy();
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setHeader("Pragma", "No-cache");
// 设置不缓存
response.setHeader("Cache-Control", "no-cache");
// 设置缓存控制器，不缓存
response.setDateHeader("Expires", 0L);
// 设置不过期。
BufferedImage bImage =
new BufferedImage(I_WIDTH, I_HEIGHT, 1);
// 生成一张“画布”
Graphics g = bImage.getGraphics();
// 获取一支“画笔”
g.setColor(Color.WHITE);
// 白色
g.fillRect(0, 0, I_WIDTH, I_HEIGHT);
// 画一个矩形,fillRect填充整个矩形
g.setColor(Color.BLUE);
// 蓝色
g.drawRect(0, 0, I_WIDTH - 1, I_HEIGHT - 1);
// 画边框,drawRect画一个空心矩形
g.setColor(Color.BLACK);
// 黑色
g.setFont(VALIDATECODE_FONT);
// 设置字体
String codeNumber =
new String(""
+ (10000 +
new Random().nextInt(89999)));
// 生成随机验证码
request.getSession().setAttribute(codeName, codeNumber);
// 将验证码保存到session里面
g.drawString(codeNumber, 7, 15);
// 将验证码画到图片上
for (
int i = 0; i < 20; i++) {
// 给图片加上20个躁点
int x =
new Random().nextInt(I_WIDTH);
int y =
new Random().nextInt(I_HEIGHT);
g.drawLine(x, y, x, y);
}
g.dispose(); // 画好了将笔收起来
ImageIO.write(bImage, "JPEG"
, response.getOutputStream());
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
@Override
public void init(ServletConfig config)
throws ServletException {
codeName = config.getInitParameter("code");
// 获取web.xml里code的值
}
}
web.xml
<servlet>
<servlet-name>ValidateCode
</servlet-name>
<servlet-class>com.ValidateCode
</servlet-class>
<init-param>
<param-name>code
</param-name>
<param-value>code
</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>ValidateCode
</servlet-name>
<url-pattern>/code
</url-pattern>
</servlet-mapping>
html
<img src="code"/>
转载于:https://www.cnblogs.com/-gap/archive/2012/06/11/2544942.html
相关资源：java web验证码 实例代码
