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 Java 实现随机验证码具体代码,具有一定的参考价值,感兴趣的小伙伴们可以参考一下
- import java.awt.Color;
- import java.awt.Font;
- import java.awt.Graphics2D;
- 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.http.HttpServlet;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- import javax.servlet.http.HttpSession;
- public class RandImage extends HttpServlet {
- /**
- * Constructor of the object.
- */
- public RandImage() {
- super();
- }
- private int imgWidth = 0; //图片宽度
- private int imgHeight = 0; //图片的高度
- private int codeCount = 0; //图片里面字符的个数
- private int x = 0;
- private int fontHeight; //字体的高度
- private int codeY;
- private String fontStyle; //字体样式
- //序列化ID 避免重复
- private static final long serialVersionUID = 128554012633034503L;
- /**
- * 初始化配置参数
- */
- public void init() throws ServletException {
- // 宽度
- String strWidth = "200";
- // 高度
- String strHeight ="80";
- // 字符个数
- String strCodeCount ="5";
- //字体
- fontStyle = "Times New Roman";
- // 将配置的信息转换成数值
- try {
- if (strWidth != null && strWidth.length() != 0) {
- imgWidth = Integer.parseInt(strWidth);
- }
- if (strHeight != null && strHeight.length() != 0) {
- imgHeight = Integer.parseInt(strHeight);
- }
- if (strCodeCount != null && strCodeCount.length() != 0) {
- codeCount = Integer.parseInt(strCodeCount);
- }
- } catch (NumberFormatException e) {
- e.printStackTrace();
- }
- x = imgWidth / (codeCount + 1); //字符间距
- fontHeight = imgHeight - 2; //字体的高度
- codeY = imgHeight - 12; // 代码高度
- }
- protected void processRequest(HttpServletRequest request,
- HttpServletResponse response) throws ServletException, IOException {
- //输出流设置
- response.setContentType("image/jpeg"); //输出格式
- response.setHeader("Pragma", "No-cache");//不缓存 重新生成
- response.setHeader("Cache-Control", "no-cache");//不缓存 重新生成
- response.setDateHeader("Expires", 0); //0秒失效 也是不缓存
- HttpSession session = request.getSession(); //获取session 会话
- // 在内存中创建图象
- BufferedImage image = new BufferedImage(imgWidth, imgHeight, BufferedImage.TYPE_INT_RGB);
- // 获取图形上下文
- Graphics2D g = image.createGraphics();
- // 生成随机类
- Random random = new Random(); //随机类
- // 设定矩形的背景色
- g.setColor(Color.WHITE);
- //填充矩形Rect为白色
- g.fillRect(0, 0, imgWidth, imgHeight);
- // 设定边框字体
- g.setFont(new Font(fontStyle, Font.PLAIN + Font.ITALIC, fontHeight));
- //设置边框的颜色
- g.setColor(new Color(55, 55, 12));
- // 画边框
- g.drawRect(0, 0, imgWidth - 1, imgHeight - 1);
- // 随机产生160条干扰线,使图象中的认证码不易被其它程序探测到
- g.setColor(getRandColor(160, 200));
- for (int i = 0; i < 160; i++) {
- int x = random.nextInt(imgWidth);
- int y = random.nextInt(imgHeight);
- int xl = random.nextInt(12);
- int yl = random.nextInt(12);
- g.drawLine(x, y, x + xl, y + yl);
- }
- // 取随机产生的认证码(4位数字)
- String sRand = "";
- int red = 0, green = 0, blue = 0;
- for (int i = 0; i < codeCount; i++) { //循环生成codeCount个随机字符
- //通过rgb三色随机得到新的颜色
- red = random.nextInt(255);
- green = random.nextInt(255);
- blue = random.nextInt(255);
- //随机得到一个0 1 2 的数字
- int wordType = random.nextInt(3);//随机得到0-2之间的3个数字
- char retWord = 0;
- //0 数字 1 小写字母 2 大写字母
- switch (wordType) {
- case 0:
- retWord = this.getSingleNumberChar(); //得到0-9的char型数字
- break;
- case 1:
- retWord = this.getLowerOrUpperChar(0); //得到小写的char型字母
- break;
- case 2:
- retWord = this.getLowerOrUpperChar(1); //得到大写的char型字母
- break;
- }
- sRand += String.valueOf(retWord); //将得到的随机字符 连接起来
- g.setColor(new Color(red, green, blue)); //设置一个颜色
- g.drawString(String.valueOf(retWord), 2+(i) * x, codeY); //将字符写到图片中 对应的位置
- }
- // 将认证码存入SESSION
- session.setAttribute("rand", sRand); //将得到的随机字符存入到session回话中,验证的时候可以调用
- // 图象生效
- g.dispose(); //释放g 对象
- ServletOutputStream responseOutputStream = response.getOutputStream(); //输出流
- // 输出图象到页面
- ImageIO.write(image, "JPEG", responseOutputStream); //以JPEG的格式输出
- // 以下关闭输入流!
- responseOutputStream.flush();//刷新并关闭流
- responseOutputStream.close();
- }
- Color getRandColor(int fc, int bc) {// 给定范围获得随机颜色
- Random random = new Random();
- if (fc > 255)
- fc = 255;
- if (bc > 255)
- bc = 255;
- int r = fc + random.nextInt(bc - fc);
- int g = fc + random.nextInt(bc - fc);
- int b = fc + random.nextInt(bc - fc);
- return new Color(r, g, b);
- }
- protected void doGet(HttpServletRequest request,
- HttpServletResponse response) throws ServletException, IOException {
- processRequest(request, response);
- }
- protected void doPost(HttpServletRequest request,
- HttpServletResponse response) throws ServletException, IOException {
- processRequest(request, response);
- }
- // 将整型随机数字转换成char返回
- private char getSingleNumberChar() {
- Random random = new Random();
- int numberResult = random.nextInt(10);
- int ret = numberResult + 48; //将字符 '0' 转换成ascall码的时候 就是48
- return (char) ret;
- }
- //得到26个字符
- private char getLowerOrUpperChar(int upper) {
- Random random = new Random();
- int numberResult = random.nextInt(26);
- int ret = 0;
- if (upper == 0) {// 小写
- ret = numberResult + 97;
- } else if (upper == 1) {// 大写
- ret = numberResult + 65;
- }
- return (char) ret;
- }
- }
来源: http://www.phperz.com/article/17/1215/358981.html