原理:
創(chuàng)新互聯(lián)服務(wù)緊隨時(shí)代發(fā)展步伐，進(jìn)行技術(shù)革新和技術(shù)進(jìn)步，經(jīng)過(guò)10年的發(fā)展和積累，已經(jīng)匯集了一批資深網(wǎng)站策劃師、設(shè)計(jì)師、專業(yè)的網(wǎng)站實(shí)施團(tuán)隊(duì)以及高素質(zhì)售后服務(wù)人員，并且完全形成了一套成熟的業(yè)務(wù)流程，能夠完全依照客戶要求對(duì)網(wǎng)站進(jìn)行成都網(wǎng)站設(shè)計(jì)、成都網(wǎng)站建設(shè)、建設(shè)、維護(hù)、更新和改版，實(shí)現(xiàn)客戶網(wǎng)站對(duì)外宣傳展示的首要目的，并為客戶企業(yè)品牌互聯(lián)網(wǎng)化提供全面的解決方案。
1.隨機(jī)生成4個(gè)數(shù)字 用到了Random類
2.對(duì)這4個(gè)數(shù)字設(shè)置字體格式 用 setFont方法
3.改變字體顏色用setColor 然后隨機(jī)生成顏色
代碼如下
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 {
// 發(fā)送圖片不能夠添加這2行代碼
// response.setContentType("text/html;charset=UTF-8");
// request.setCharacterEncoding("UTF-8");
int width=100;
int height=50;
//獲得一張圖片
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("宋體",Font.BOLD,30));
Random random=new Random();
// 填充的字符串
String str="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
//緩存生成的驗(yàn)證碼
StringBuffer stringbuffer=new StringBuffer();
//隨機(jī)生成驗(yàn)證碼的顏色和字符
for(int i=0;i4;i++)
{ //設(shè)置隨機(jī)顏色
g.setColor(new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256)));
int index=random.nextInt(62);//這里的62就是從填充字符段中隨意選取一個(gè)位置
String str1=str.substring(index,index+1);
g.drawString(str1, 20*i, 30);//x,y數(shù)值設(shè)置太小會(huì)顯示不出來(lái)
stringbuffer.append(str1);
}
//將生成的驗(yàn)證碼存到服務(wù)器
request.getSession().setAttribute("checkcode", stringbuffer.toString());//key和value
//將圖片發(fā)送給瀏覽器
ImageIO.write(image, "jpg", response.getOutputStream());
}
}
用戶登錄界面代碼
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");// 設(shè)置服務(wù)器發(fā)送給瀏覽器的編碼方式
request.setCharacterEncoding("UTF-8"); // 客戶端向服務(wù)器提交的數(shù)據(jù)的解碼方式
// 獲得用戶提交的數(shù)據(jù)
String checkcode = request.getParameter("checkcode");
System.out.println(checkcode);
// 判斷輸入的驗(yàn)證碼是不是符合
HttpSession session = request.getSession();// session是存放數(shù)據(jù)的地方
String str = (String) session.getAttribute("checkcode");
if (str != null) {
if (checkcode.compareToIgnoreCase(str) == 0) // 驗(yàn)證碼忽略大小寫
response.getWriter().println("驗(yàn)證碼輸入正確");
else
response.getWriter().println("驗(yàn)證碼輸入錯(cuò)誤");
}
else response.getWriter().println("驗(yàn)證碼失效");
// 使用完的驗(yàn)證碼信息要?jiǎng)h除,返回原頁(yè)面再輸一次,驗(yàn)證碼就失效了
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?{
//?驗(yàn)證碼字符集
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'};
//?字符數(shù)量
private?static?final?int?SIZE?=?4;
//?干擾線數(shù)量
private?static?final?int?LINES?=?5;
//?寬度
private?static?final?int?WIDTH?=?80;
//?高度
private?static?final?int?HEIGHT?=?40;
//?字體大小
private?static?final?int?FONT_SIZE?=?30;
/**
*?生成隨機(jī)驗(yàn)證碼及圖片
*?返回的數(shù)組中，第1個(gè)值是驗(yàn)證碼，第2個(gè)值是圖片
*/
public?static?Object[]?createImage()?{
StringBuffer?sb?=?new?StringBuffer();
//?1.創(chuàng)建空白圖片
BufferedImage?image?=?new?BufferedImage(
WIDTH,?HEIGHT,?BufferedImage.TYPE_INT_RGB);
//?2.獲取圖片畫筆
Graphics?graphic?=?image.getGraphics();
//?3.設(shè)置畫筆顏色
graphic.setColor(Color.LIGHT_GRAY);
//?4.繪制矩形背景
graphic.fillRect(0,?0,?WIDTH,?HEIGHT);
//?5.畫隨機(jī)字符
Random?ran?=?new?Random();
for?(int?i?=?0;?i?SIZE;?i++)?{
//?取隨機(jī)字符索引
int?n?=?ran.nextInt(chars.length);
//?設(shè)置隨機(jī)顏色
graphic.setColor(getRandomColor());
//?設(shè)置字體大小
graphic.setFont(new?Font(
null,?Font.BOLD?+?Font.ITALIC,?FONT_SIZE));
//?畫字符
graphic.drawString(
chars[n]?+?"",?i?*?WIDTH?/?SIZE,?HEIGHT?/?2);
//?記錄字符
sb.append(chars[n]);
}
//?6.畫干擾線
for?(int?i?=?0;?i??LINES;?i++)?{
//?設(shè)置隨機(jī)顏色
graphic.setColor(getRandomColor());
//?隨機(jī)畫線
graphic.drawLine(ran.nextInt(WIDTH),?ran.nextInt(HEIGHT),
ran.nextInt(WIDTH),?ran.nextInt(HEIGHT));
}
//?7.返回驗(yàn)證碼和圖片
return?new?Object[]{sb.toString(),?image};
}
/**
*?隨機(jī)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();
}
}
不知道你問(wèn)的是不是生成這種圖片驗(yàn)證碼？如果只要一個(gè)隨機(jī)四位數(shù) 那這行代碼就夠了(new Random().nextInt(9000) + 1000;),如果是生成頁(yè)面圖片驗(yàn)證碼就是下面的了: //設(shè)定 響應(yīng)模式 resp.setContentType("image/jpeg"); // 生成令牌環(huán)數(shù)據(jù); Integer token = new Random().nextInt(9000) + 1000; // 保存令牌環(huán)數(shù)據(jù)到session中 req.getSession().setAttribute(IMAGE_TOKEN_NAME, token); // 生成令牌環(huán)圖片 ServletOutputStream out = resp.getOutputStream(); BufferedImage img = new BufferedImage(60, 20, BufferedImage.TYPE_INT_RGB); Graphics g = img.getGraphics(); g.setColor(Color.YELLOW); g.fillRect(0, 0, img.getWidth(), img.getHeight()); g.setColor(Color.BLUE); g.setFont(new Font("", Font.BOLD, 18)); g.drawString(String.valueOf(token), 10, 16); ImageIO.write(img, "jpg", out); out.close();
下面簡(jiǎn)單的介紹他們的功能和用途，執(zhí)行效率等。每個(gè)都有各自的優(yōu)缺點(diǎn)看你是做甚什么方面的研究開發(fā)用。.net，是網(wǎng)站編程，現(xiàn)在很多都用這個(gè)，但是這個(gè)語(yǔ)言編程都有統(tǒng)一思路，很好掌握。窒息那個(gè)效率不是很高；php 支持跨平臺(tái)，很容易學(xué)會(huì)，執(zhí)行的效率很高；asp是ASP.net的前身，它比較穩(wěn)定，比.net要弱一點(diǎn)。但是比.net好學(xué)。jsp 是網(wǎng)頁(yè)編程，這個(gè)學(xué)習(xí)大約一周就能搞定，不過(guò)這個(gè)得多實(shí)踐，不然的話，時(shí)間長(zhǎng)了，就容易忘記。
我自己做的系統(tǒng)里面用作驗(yàn)證碼的JSP的%@page contentType="image/jpeg;charset=utf-8"%%@page import="java.util.*,java.awt.*,java.awt.image.*,javax.imageio.*" %%@ page import="java.io.OutputStream" %html body %! Color getRandColor(int fc,int bc) { Random rd=new Random(); if(fc255) fc=255; if(bc255) bc=255; int red=fc+rd.nextInt(bc-fc); int green=fc+rd.nextInt(bc-fc); int blue=fc+rd.nextInt(bc-fc); return new Color(red,green,blue); } % % Random r=new Random(); response.addHeader("Pragma","No-cache"); response.addHeader("Cache-Control","no-cache"); response.addDateHeader("expires",0); int width=90; int height=23; BufferedImage pic=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); Graphics gc=pic.getGraphics(); gc.setColor(getRandColor(200,250)); gc.fillRect(0,0,width,height); String[] rNum ={"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"}; int[] style = {Font.PLAIN,Font.BOLD,Font.ITALIC,Font.PLAIN+Font.BOLD, Font.BOLD+Font.ITALIC,Font.PLAIN+Font.ITALIC,Font.PLAIN+Font.BOLD+Font.ITALIC}; gc.setColor(Color.WHITE); gc.drawLine(0,30,90,10); gc.setColor(getRandColor(160,200)); for (int i=0;i50;i++) { int x = r.nextInt(width); int y = r.nextInt(height); int xl = r.nextInt(10); int yl = r.nextInt(10); gc.drawLine(x,y,x+xl,y+yl); } gc.setColor(getRandColor(60,150)); String rt = ""; for(int i=0;i4;i++){ String temp = rNum[r.nextInt(62)]; rt = rt+temp; gc.setFont(new Font("Times New Roman",style[r.nextInt(7)],15)); gc.drawString(temp,5+i*15+r.nextInt(10),10+r.nextInt(10)); } gc.dispose(); session.setAttribute("randNum",rt); OutputStream os=response.getOutputStream(); ImageIO.write(pic,"JPEG",os); System.out.println("當(dāng)前驗(yàn)證碼為:"+session.getAttribute("randNum")); os.flush(); os.close(); os=null; response.flushBuffer(); out.clear(); out = pageContext.pushBody(); % /body/html
現(xiàn)在許多系統(tǒng)的注冊(cè) 登錄或者發(fā)布信息模塊都添加的隨機(jī)驗(yàn)證碼功能 就是為了避免自動(dòng)注冊(cè)程序或者自動(dòng)發(fā)布程序的使用
驗(yàn)證碼實(shí)際上就是隨機(jī)選擇一些字符以圖片的形式展現(xiàn)在頁(yè)面上 如果進(jìn)行提交操作的同時(shí)需要將圖片上的字符同時(shí)提交 如果提交的字符與服務(wù)器session保存的不同 則認(rèn)為提交信息無(wú)效 為了避免自動(dòng)程序分析解析圖片 通常會(huì)在圖片上隨機(jī)生成一些干擾線或者將字符進(jìn)行扭曲 增加自動(dòng)識(shí)別驗(yàn)證碼的難度
在這里 我們使用java實(shí)現(xiàn)驗(yàn)證碼
%@ page contentType= image/jpeg import= java awt * java awt image * java util * javax imageio * %
%!
Color getRandColor(int fc int bc){//給定范圍獲得隨機(jī)顏色
Random random = new Random();
if(fc ) fc= ;
if(bc ) bc= ;
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);
}
%
%
//設(shè)置頁(yè)面不緩存
response setHeader( Pragma No cache );
response setHeader( Cache Control no cache );
response setDateHeader( Expires );
// 在內(nèi)存中創(chuàng)建圖象
int width= height= ;
BufferedImage image = new BufferedImage(width height BufferedImage TYPE_INT_RGB);
// 獲取圖形上下文
Graphics g = image getGraphics();
//生成隨機(jī)類
Random random = new Random();
// 設(shè)定背景色
g setColor(getRandColor( ));
g fillRect( width height);
//設(shè)定字體
g setFont(new Font( Times New Roman Font PLAIN ));
// 隨機(jī)產(chǎn)生 條干擾線 使圖象中的認(rèn)證碼不易被其它程序探測(cè)到
g setColor(getRandColor( ));
for (int i= ;i ;i++)
{
int x = random nextInt(width);
int y = random nextInt(height);
int xl = random nextInt( );
int yl = random nextInt( );
g drawLine(x y x+xl y+yl);
}
// 取隨機(jī)產(chǎn)生的認(rèn)證碼( 位數(shù)字)
String codeList = ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz ;
String sRand= ;
for (int i= ;i ;i++){
int a=random nextInt(codeList length() );
String rand=codeList substring(a a+ );
sRand+=rand;
// 將認(rèn)證碼顯示到圖象中
g setColor(new Color( +random nextInt( ) +random nextInt( ) +random nextInt( )));//調(diào)用函數(shù)出來(lái)的顏色相同 可能是因?yàn)榉N子太接近 所以只能直接生成
g drawString(rand *i+ );
}
// 將認(rèn)證碼存入SESSION
session setAttribute( rand sRand);
// 圖象生效
g dispose();
// 輸出圖象到頁(yè)面
ImageIO write(image JPEG response getOutputStream());
out clear();
out = pageContext pushBody();
lishixinzhi/Article/program/Java/hx/201311/25536
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