java 是一种可以撰写跨平台应用软件的面向对象的程序设计语言,是由 Sun Microsystems 公司于 1995 年 5 月推出的 Java 程序设计语言和 Java 平台(即 JavaEE(j2ee), JavaME(j2me), JavaSE(j2se))的总称。
这篇文章主要为大家详细介绍了简单实现 Java 验证码功能的代码,具有一定的参考价值,感兴趣的小伙伴们可以参考一下
今晚看到网上有关验证码的实现的代码,很早就想写一个了,感觉验证码挺有意思的,于是就写了一个,然而后来一直加载不出图片。尝试了很多方法,后来终于解决了,原来是我项目里面的 web.xml 中没有部署 servlet 的映射,web.xml 如下图:
运行效果如下:
代码如下:
- package model;
- import javax.imageio.ImageIO;
- import java.awt. * ;
- import java.awt.image.BufferedImage;
- import java.io.IOException;
- import java.io.OutputStream;
- import java.util.Random;
- /**
- * Created by Petty on 2017/5/4.
- */
- public class VCode {
- private int w; //图片宽
- private int h; //图片高
- private Color bgColor = new Color(240, 240, 240); //背景色
- private Random random = new Random(); //随机对象
- //设置字体范围
- private String[] fontNames = {
- "宋体",
- "华文楷体",
- "黑体",
- "华文新魏",
- "华文隶书",
- "微软雅黑",
- "楷体"
- };
- //设置字体样式范围
- private int[] fontstyle = {
- 0,
- 1,
- 2,
- 3
- };
- //设置字号范围
- private int[] fontSizes = {
- 24,
- 25,
- 26,
- 27,
- 28
- };
- //设置所有字符串范围
- private String codes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
- //无参数构造函数
- public VCode() {
- }
- //带宽和高的构造函数
- public VCode(int w, int h) {
- this.w = w;
- this.h = h;
- }
- //返回一张背景图片
- private BufferedImage createImage() {
- /**
- * 1.创建图片 2.设置背景色
- */
- //创建图片
- BufferedImage img = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
- //设置背景色
- Graphics g = img.getGraphics();
- g.setColor(bgColor);
- g.fillRect(0, 0, w, h);
- return img;
- }
- // 随机返回字体颜色
- private Color randomColor() {
- int r = random.nextInt(256);
- int g = random.nextInt(256);
- int b = random.nextInt(256);
- return new Color(r, g, b);
- }
- //随机返回字体样式
- private Font randomFont() {
- //随机生成字体下标,随机从给定的范围内获取一个字体
- int index = random.nextInt(fontNames.length);
- String name = fontNames[index];
- //随机生成字体样式下标,随即从给定的范围内获取一个字体样式
- index = random.nextInt(fontstyle.length);
- int style = fontstyle[index];
- //随机生成字体大小下标,随机从给定的范围内获取一个字体大小
- index = random.nextInt(fontSizes.length);
- int size = fontSizes[index];
- return new Font(name, style, size);
- }
- //随机返回字体内容
- private String randomChar() {
- int index = random.nextInt(codes.length());
- return codes.charAt(index) + "";
- }
- //随机返回几条干扰线
- private void getLine(BufferedImage img) {
- //设置干扰线的宽度为1.5倍宽,随机画五条
- 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);
- }
- }
- //用户调用该方法获取图片
- public BufferedImage getImage() {
- /**
- * 随机生成字符0-9A-Za-z,设置字体,字号,是否粗体,字符颜色,都是随机的
- */
- BufferedImage img = createImage();
- this.getLine(img);
- //获取画笔
- Graphics g = img.getGraphics();
- //画内容
- for (int i = 0; i < 4; i++) {
- g.setColor(this.randomColor()); //获取随机颜色
- g.setFont(this.randomFont()); //获取随机字体
- g.drawString(this.randomChar(), w / 4 * i, h - 5); //获取字符串随机内容
- }
- return img;
- }
- //用户调用该方法保存图片到本地
- public void saveImage(BufferedImage img, OutputStream ous) {
- try {
- ImageIO.write(img, "JPEG", ous);
- } catch(IOException e) {
- e.printStackTrace();
- }
- }
- }
- package model;
- import javax.servlet.ServletException;
- import javax.servlet.annotation.WebServlet;
- import javax.servlet.http.HttpServlet;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- import java.awt.image.BufferedImage;
- import java.io.IOException;
- /**
- * Created by Petty on 2017/5/4.
- */
- @WebServlet(name = "BServlet") public class BServlet extends HttpServlet {
- public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException,
- IOException {
- VCode v = new VCode(70, 35);
- BufferedImage img = v.getImage();
- v.saveImage(img, response.getOutputStream());
- }
- public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException,
- IOException {
- VCode v = new VCode(70, 35);
- BufferedImage img = v.getImage();
- v.saveImage(img, response.getOutputStream());
- }
- }
- <%-- Created by IntelliJ IDEA. User: Petty Date: 2017/5/4 Time: 22:28
- To change this template use File | Settings | File Templates. --%>
- <%@ page contentType="text/html;charset=UTF-8" language="java" %>
- <html>
- <head>
- <title>
- 一次性验证码
- </title>
- </head>
- <body>
- <form action="" method="get">
- <table align="center">
- <tr>
- <td>
- <img id="img" alt="" src="servlet/BServlet" onclick="changeNext()">
- </td>
- </tr>
- </table>
- </form>
- </body>
- </html>
- <script type="text/javascript">
- function changeNext() {
- var a = document.getElementById("img");
- a.src = "servlet/BServlet?a=" + new Date().getTime();
- }
- </script>
来源: http://www.phperz.com/article/18/0102/357186.html