原理:
创新互联响应式网站特点就是不管在电脑、平板还是手机上,成都h5网站建设都会根据屏幕尺寸自动调节大小、图片分辨率,并且融入一定的动画特效,让网站看起来非常的美观大方。从网站需求对接到网站制作设计、从代码编写到项目上线运维,技术人员全程跟踪,快速响应
1.随机生成4个数字 用到了Random类
2.对这4个数字设置字体格式 用 setFont方法
3.改变字体颜色用setColor 然后随机生成颜色
代码如下
package s1;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.jms.Session;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class GetImage extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 发送图片不能够添加这2行代码
// response.setContentType("text/html;charset=UTF-8");
// request.setCharacterEncoding("UTF-8");
int width=100;
int height=50;
//获得一张图片
BufferedImage image=new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g=image.getGraphics();
g.setColor(Color.WHITE);
g.fillRect(1, 1, width-2, height-2);
g.setFont(new Font("宋体",Font.BOLD,30));
Random random=new Random();
// 填充的字符串
String str="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
//缓存生成的验证码
StringBuffer stringbuffer=new StringBuffer();
//随机生成验证码的颜色和字符
for(int i=0;i4;i++)
{ //设置随机颜色
g.setColor(new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256)));
int index=random.nextInt(62);//这里的62就是从填充字符段中随意选取一个位置
String str1=str.substring(index,index+1);
g.drawString(str1, 20*i, 30);//x,y数值设置太小会显示不出来
stringbuffer.append(str1);
}
//将生成的验证码存到服务器
request.getSession().setAttribute("checkcode", stringbuffer.toString());//key和value
//将图片发送给浏览器
ImageIO.write(image, "jpg", response.getOutputStream());
}
}
用户登录界面代码
package s1;
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;
import javax.servlet.http.HttpSession;
public class Login extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");// 设置服务器发送给浏览器的编码方式
request.setCharacterEncoding("UTF-8"); // 客户端向服务器提交的数据的解码方式
// 获得用户提交的数据
String checkcode = request.getParameter("checkcode");
System.out.println(checkcode);
// 判断输入的验证码是不是符合
HttpSession session = request.getSession();// session是存放数据的地方
String str = (String) session.getAttribute("checkcode");
if (str != null) {
if (checkcode.compareToIgnoreCase(str) == 0) // 验证码忽略大小写
response.getWriter().println("验证码输入正确");
else
response.getWriter().println("验证码输入错误");
}
else response.getWriter().println("验证码失效");
// 使用完的验证码信息要删除,返回原页面再输一次,验证码就失效了
session.removeAttribute("checkcode");
}
}
package util;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
public final class ImageUtil {
// 验证码字符集
private static final char[] chars = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};
// 字符数量
private static final int SIZE = 4;
// 干扰线数量
private static final int LINES = 5;
// 宽度
private static final int WIDTH = 80;
// 高度
private static final int HEIGHT = 40;
// 字体大小
private static final int FONT_SIZE = 30;
/**
* 生成随机验证码及图片
* 返回的数组中,第1个值是验证码,第2个值是图片
*/
public static Object[] createImage() {
StringBuffer sb = new StringBuffer();
// 1.创建空白图片
BufferedImage image = new BufferedImage(
WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
// 2.获取图片画笔
Graphics graphic = image.getGraphics();
// 3.设置画笔颜色
graphic.setColor(Color.LIGHT_GRAY);
// 4.绘制矩形背景
graphic.fillRect(0, 0, WIDTH, HEIGHT);
// 5.画随机字符
Random ran = new Random();
for (int i = 0; i SIZE; i++) {
// 取随机字符索引
int n = ran.nextInt(chars.length);
// 设置随机颜色
graphic.setColor(getRandomColor());
// 设置字体大小
graphic.setFont(new Font(
null, Font.BOLD + Font.ITALIC, FONT_SIZE));
// 画字符
graphic.drawString(
chars[n] + "", i * WIDTH / SIZE, HEIGHT / 2);
// 记录字符
sb.append(chars[n]);
}
// 6.画干扰线
for (int i = 0; i LINES; i++) {
// 设置随机颜色
graphic.setColor(getRandomColor());
// 随机画线
graphic.drawLine(ran.nextInt(WIDTH), ran.nextInt(HEIGHT),
ran.nextInt(WIDTH), ran.nextInt(HEIGHT));
}
// 7.返回验证码和图片
return new Object[]{sb.toString(), image};
}
/**
* 随机取色
*/
public static Color getRandomColor() {
Random ran = new Random();
Color color = new Color(ran.nextInt(256),
ran.nextInt(256), ran.nextInt(256));
return color;
}
public static void main(String[] args) throws IOException {
Object[] objs = createImage();
BufferedImage image = (BufferedImage) objs[1];
OutputStream os = new FileOutputStream("d:/1.png");
ImageIO.write(image, "jpeg", os);
os.close();
}
}
package com.servlet;
import java.awt.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.io.*;
import java.util.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.imageio.ImageIO;
public class PictureCheckCode extends HttpServlet {
private static final long serialVersionUID = 1L;
public PictureCheckCode() {
super();
}
public void destroy() {
super.destroy();
}
public void init() throws ServletException {
super.init();
}
/*该方法主要作用是获得随机生成的颜色*/
public Color getRandColor(int s,int e){
Random random=new Random ();
if(s255) s=255;
if(e255) e=255;
int r,g,b;
r=s+random.nextInt(e-s); //随机生成RGB颜色中的r值
g=s+random.nextInt(e-s); //随机生成RGB颜色中的g值
b=s+random.nextInt(e-s); //随机生成RGB颜色中的b值
return new Color(r,g,b);
}
@Override
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//设置不缓存图片
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "No-cache");
response.setDateHeader("Expires", 0);
//指定生成的响应图片,一定不能缺少这句话,否则错误.
response.setContentType("image/jpeg");
int width=86,height=22; //指定生成验证码的宽度和高度
BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); //创建BufferedImage对象,其作用相当于一图片
Graphics g=image.getGraphics(); //创建Graphics对象,其作用相当于画笔
Graphics2D g2d=(Graphics2D)g; //创建Grapchics2D对象
Random random=new Random();
Font mfont=new Font("楷体",Font.BOLD,16); //定义字体样式
g.setColor(getRandColor(200,250));
g.fillRect(0, 0, width, height); //绘制背景
g.setFont(mfont); //设置字体
g.setColor(getRandColor(180,200));
//绘制100条颜色和位置全部为随机产生的线条,该线条为2f
for(int i=0;i100;i++){
int x=random.nextInt(width-1);
int y=random.nextInt(height-1);
int x1=random.nextInt(6)+1;
int y1=random.nextInt(12)+1;
BasicStroke bs=new BasicStroke(2f,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL); //定制线条样式
Line2D line=new Line2D.Double(x,y,x+x1,y+y1);
g2d.setStroke(bs);
g2d.draw(line); //绘制直线
}
//输出由英文,数字,和中文随机组成的验证文字,具体的组合方式根据生成随机数确定。
String sRand="";
String ctmp="";
int itmp=0;
//制定输出的验证码为四位
for(int i=0;i4;i++){
switch(random.nextInt(3)){
case 1: //生成A-Z的字母
itmp=random.nextInt(26)+65;
ctmp=String.valueOf((char)itmp);
break;
case 2: //生成汉字
String[] rBase={"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"};
//生成第一位区码
int r1=random.nextInt(3)+11;
String str_r1=rBase[r1];
//生成第二位区码
int r2;
if(r1==13){
r2=random.nextInt(7);
}else{
r2=random.nextInt(16);
}
String str_r2=rBase[r2];
//生成第一位位码
int r3=random.nextInt(6)+10;
String str_r3=rBase[r3];
//生成第二位位码
int r4;
if(r3==10){
r4=random.nextInt(15)+1;
}else if(r3==15){
r4=random.nextInt(15);
}else{
r4=random.nextInt(16);
}
String str_r4=rBase[r4];
//将生成的机内码转换为汉字
byte[] bytes=new byte[2];
//将生成的区码保存到字节数组的第一个元素中
String str_12=str_r1+str_r2;
int tempLow=Integer.parseInt(str_12, 16);
bytes[0]=(byte) tempLow;
//将生成的位码保存到字节数组的第二个元素中
String str_34=str_r3+str_r4;
int tempHigh=Integer.parseInt(str_34, 16);
bytes[1]=(byte)tempHigh;
ctmp=new String(bytes);
break;
default:
itmp=random.nextInt(10)+48;
ctmp=String.valueOf((char)itmp);
break;
}
sRand+=ctmp;
Color color=new Color(20+random.nextInt(110),20+random.nextInt(110),random.nextInt(110));
g.setColor(color);
//将生成的随机数进行随机缩放并旋转制定角度 PS.建议不要对文字进行缩放与旋转,因为这样图片可能不正常显示
/*将文字旋转制定角度*/
Graphics2D g2d_word=(Graphics2D)g;
AffineTransform trans=new AffineTransform();
trans.rotate((45)*3.14/180,15*i+8,7);
/*缩放文字*/
float scaleSize=random.nextFloat()+0.8f;
if(scaleSize1f) scaleSize=1f;
trans.scale(scaleSize, scaleSize);
g2d_word.setTransform(trans);
g.drawString(ctmp, 15*i+18, 14);
}
HttpSession session=request.getSession(true);
session.setAttribute("randCheckCode", sRand);
g.dispose(); //释放g所占用的系统资源
ImageIO.write(image,"JPEG",response.getOutputStream()); //输出图片
}
}
JFrame jFrame = new JFrame("提示");
jFrame.setLayout(null);
jFrame.setResizable(false);
jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Dimension dimension = Toolkit.getDefaultToolkit().getScreenSize();
jFrame.setBounds((int)(dimension.getWidth() - 300) / 2, (int)(dimension.getHeight() - 200) / 2, 300, 200);
JLabel label1 = new JLabel("请输入验证码:");
label1.setBounds(5, 80, 100, 20);
jFrame.add(label1);
Random random = new Random();
String code = "";
for(int i = 0; i 4; i++) {
code += random.nextInt(10);
}
JLabel label2 = new JLabel(String.valueOf(code));
label2.setBounds(160, 80, 40, 20);
jFrame.add(label2);
JTextField text = new JTextField();
text.setBounds(100, 80, 50, 20);
jFrame.add(text);
jFrame.setVisible(true);
package com.bbs.servlet;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
public class Image extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("image/jpeg");
OutputStream out = response.getOutputStream();
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);
int width = 60, height = 20;
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
// 获取图形上下文
Graphics g = image.getGraphics();
// 生成随机类
Random random = new Random();
// 设定背景色
g.setColor(getRandColor(200, 250));
g.fillRect(0, 0, width, height);
// 设定字体
g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
// 随机产生155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(180, 200));
for (int i = 0; i 155; i++) {
int x = random.nextInt(width);
int y = random.nextInt(height);
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 =setRandValue(request);
if(sRand!=null)
for (int i = 0; i sRand.length(); i++) {
g.setColor(new Color(20 + random.nextInt(200), 20 + random
.nextInt(200), 20 + random.nextInt(200)));
// 调用函数出来的颜色相同,可能是因为种子太接近,所以只能直接生成
g.drawString(sRand.charAt(i) + "", 13 * i + 6, 16);
}
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(image);
// 图象生效
g.dispose();
// 输出图象到页面
// ImageIO.write(image, "JPG", response.getOutputStream());
out.flush();
out.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);
}
//48-57对应0-9;65-90对应A-Z;97-122对应a-z;
String setRandValue(HttpServletRequest request) {
Random random = new Random();
String sRand = "";
//这里是生成验证码的位数
for (int i = 0; i 4; i++) {
char c = 0;
int k = random.nextInt(3);
switch (k) {
case 0:
c = (char) (random.nextInt(10) + 48);
break;
case 1:
c = (char) (random.nextInt(26) + 65);
break;
case 2:
c = (char) (random.nextInt(26) + 97);
}
sRand += c;
}
request.getSession().setAttribute("rands", sRand);
return sRand;
}
}
Java如何实现验证码验证功能呢?日常生活中,验证码随处可见,他可以在一定程度上保护账号安全,那么他是怎么实现的呢?
Java实现验证码验证功能其实非常简单:用到了一个Graphics类在画板上绘制字母,随机选取一定数量的字母随机生成,然后在画板上随机生成几条干扰线。
首先,写一个验证码生成帮助类,用来绘制随机字母:
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
public final class GraphicHelper {
/**
* 以字符串形式返回生成的验证码,同时输出一个图片
*
* @param width
* 图片的宽度
* @param height
* 图片的高度
* @param imgType
* 图片的类型
* @param output
* 图片的输出流(图片将输出到这个流中)
* @return 返回所生成的验证码(字符串)
*/
public static String create(final int width, final int height, final String imgType, OutputStream output) {
StringBuffer sb = new StringBuffer();
Random random = new Random();
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics graphic = image.getGraphics();
graphic.setColor(Color.getColor("F8F8F8"));
graphic.fillRect(0, 0, width, height);
Color[] colors = new Color[] { Color.BLUE, Color.GRAY, Color.GREEN, Color.RED, Color.BLACK, Color.ORANGE,
Color.CYAN };
// 在 "画板"上生成干扰线条 ( 50 是线条个数)
for (int i = 0; i 50; i++) {
graphic.setColor(colors[random.nextInt(colors.length)]);
final int x = random.nextInt(width);
final int y = random.nextInt(height);
final int w = random.nextInt(20);
final int h = random.nextInt(20);
final int signA = random.nextBoolean() ? 1 : -1;
final int signB = random.nextBoolean() ? 1 : -1;
graphic.drawLine(x, y, x + w * signA, y + h * signB);
}
// 在 "画板"上绘制字母
graphic.setFont(new Font("Comic Sans MS", Font.BOLD, 30));
for (int i = 0; i 6; i++) {
final int temp = random.nextInt(26) + 97;
String s = String.valueOf((char) temp);
sb.append(s);
graphic.setColor(colors[random.nextInt(colors.length)]);
graphic.drawString(s, i * (width / 6), height - (height / 3));
}
graphic.dispose();
try {
ImageIO.write(image, imgType, output);
} catch (IOException e) {
e.printStackTrace();
}
return sb.toString();
}
}
接着,创建一个servlet,用来固定图片大小,以及处理验证码的使用场景,以及捕获页面生成的验证码(捕获到的二维码与用户输入的验证码一致才能通过)。
import java.io.OutputStream;
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 javax.servlet.http.HttpSession;
@WebServlet(urlPatterns = "/verify/regist.do" )
public class VerifyCodeServlet extends HttpServlet {
private static final long serialVersionUID = 3398560501558431737L;
@Override
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 获得 当前请求 对应的 会话对象
HttpSession session = request.getSession();
// 从请求中获得 URI ( 统一资源标识符 )
String uri = request.getRequestURI();
System.out.println("hello : " + uri);
final int width = 180; // 图片宽度
final int height = 40; // 图片高度
final String imgType = "jpeg"; // 指定图片格式 (不是指MIME类型)
final OutputStream output = response.getOutputStream(); // 获得可以向客户端返回图片的输出流
// (字节流)
// 创建验证码图片并返回图片上的字符串
String code = GraphicHelper.create(width, height, imgType, output);
System.out.println("验证码内容: " + code);
// 建立 uri 和 相应的 验证码 的关联 ( 存储到当前会话对象的属性中 )
session.setAttribute(uri, code);
System.out.println(session.getAttribute(uri));
}
}
接着写一个HTML注册页面用来检验一下:
html
head
meta charset="UTF-8"
title注册/title
link rel="stylesheet" href="styles/general.css"
link rel="stylesheet" href="styles/cell.css"
link rel="stylesheet" href="styles/form.css"
script type="text/javascript" src="js/ref.js"/script
style type="text/css"
.logo-container {
margin-top: 50px ;
}
.logo-container img {
width: 100px ;
}
.message-container {
height: 80px ;
}
.link-container {
height: 40px ;
line-height: 40px ;
}
.link-container a {
text-decoration: none ;
}
/style
/head
body
div class="container form-container"
form action="/wendao/regist.do" method="post"
div class="form" !-- 注册表单开始 --
div class="form-row"
span class="cell-1"
i class="fa fa-user"/i
/span
span class="cell-11" style="text-align: left;"
input type="text" name="username" placeholder="请输入用户名"
/span
/div
div class="form-row"
span class="cell-1"
i class="fa fa-key"/i
/span
span class="cell-11" style="text-align: left;"
input type="password" name="password" placeholder="请输入密码"
/span
/div
div class="form-row"
span class="cell-1"
i class="fa fa-keyboard-o"/i
/span
span class="cell-11" style="text-align: left;"
input type="password" name="confirm" placeholder="请确认密码"
/span
/div
div class="form-row"
span class="cell-7"
input type="text" name="verifyCode" placeholder="请输入验证码"
/span
span class="cell-5" style="text-align: center;"
img src="/demo/verify/regist.do" onclick="myRefersh(this)"
/span
/div
div class="form-row" style="border: none;"
span class="cell-6" style="text-align: left"
input type="reset" value="重置"
/span
span class="cell-6" style="text-align:right;"
input type="submit" value="注册"
/span
/div
/div !-- 注册表单结束 --
/form
/div
/body
/html
效果如下图:
在控制台接收到的图片中验证码的变化如下:
当点击刷新页面的时候,验证码也会随着变化,但我们看不清验证码时,只要点击验证码就会刷新,这样局部的刷新可以用JavaScript来实现。
在img
src="/demo/verify/regist.do"中,添加一个问号和一串后缀数字,当刷新时让后缀数字不断改变,那么形成的验证码也会不断变化,我们可以采用的一种办法是后缀数字用date代替,date获取本机时间,时间是随时变的,这样就保证了刷新验证码可以随时变化。
代码如下:
function myRefersh( e ) {
const source = e.src ; // 获得原来的 src 中的内容
//console.log( "source : " + source ) ;
var index = source.indexOf( "?" ) ; // 从 source 中寻找 ? 第一次出现的位置 (如果不存在则返回 -1 )
//console.log( "index : " + index ) ;
if( index -1 ) { // 如果找到了 ? 就进入内部
var s = source.substring( 0 , index ) ; // 从 source 中截取 index 之前的内容 ( index 以及 index 之后的内容都被舍弃 )
//console.log( "s : " + s ) ;
var date = new Date(); // 创建一个 Date 对象的 一个 实例
var time = date.getTime() ; // 从 新创建的 Date 对象的实例中获得该时间对应毫秒值
e.src = s + "?time=" + time ; // 将 加了 尾巴 的 地址 重新放入到 src 上
//console.log( e.src ) ;
} else {
var date = new Date();
e.src = source + "?time=" + date.getTime();
}
}
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