原理:
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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");
}
}
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
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();
}
/*該方法主要作用是獲得隨機(jī)生成的顏色*/
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); //隨機(jī)生成RGB顏色中的r值
g=s+random.nextInt(e-s); //隨機(jī)生成RGB顏色中的g值
b=s+random.nextInt(e-s); //隨機(jī)生成RGB顏色中的b值
return new Color(r,g,b);
}
@Override
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//設(shè)置不緩存圖片
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "No-cache");
response.setDateHeader("Expires", 0);
//指定生成的響應(yīng)圖片,一定不能缺少這句話,否則錯(cuò)誤.
response.setContentType("image/jpeg");
int width=86,height=22; //指定生成驗(yàn)證碼的寬度和高度
BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); //創(chuàng)建BufferedImage對(duì)象,其作用相當(dāng)于一圖片
Graphics g=image.getGraphics(); //創(chuàng)建Graphics對(duì)象,其作用相當(dāng)于畫筆
Graphics2D g2d=(Graphics2D)g; //創(chuàng)建Grapchics2D對(duì)象
Random random=new Random();
Font mfont=new Font("楷體",Font.BOLD,16); //定義字體樣式
g.setColor(getRandColor(200,250));
g.fillRect(0, 0, width, height); //繪制背景
g.setFont(mfont); //設(shè)置字體
g.setColor(getRandColor(180,200));
//繪制100條顏色和位置全部為隨機(jī)產(chǎn)生的線條,該線條為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); //定制線條樣式
Line2D line=new Line2D.Double(x,y,x+x1,y+y1);
g2d.setStroke(bs);
g2d.draw(line); //繪制直線
}
//輸出由英文，數(shù)字，和中文隨機(jī)組成的驗(yàn)證文字，具體的組合方式根據(jù)生成隨機(jī)數(shù)確定。
String sRand="";
String ctmp="";
int itmp=0;
//制定輸出的驗(yàn)證碼為四位
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: //生成漢字
String[] rBase={"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"};
//生成第一位區(qū)碼
int r1=random.nextInt(3)+11;
String str_r1=rBase[r1];
//生成第二位區(qū)碼
int r2;
if(r1==13){
r2=random.nextInt(7);
}else{
r2=random.nextInt(16);
}
String str_r2=rBase[r2];
//生成第一位位碼
int r3=random.nextInt(6)+10;
String str_r3=rBase[r3];
//生成第二位位碼
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];
//將生成的機(jī)內(nèi)碼轉(zhuǎn)換為漢字
byte[] bytes=new byte[2];
//將生成的區(qū)碼保存到字節(jié)數(shù)組的第一個(gè)元素中
String str_12=str_r1+str_r2;
int tempLow=Integer.parseInt(str_12, 16);
bytes[0]=(byte) tempLow;
//將生成的位碼保存到字節(jié)數(shù)組的第二個(gè)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);
//將生成的隨機(jī)數(shù)進(jìn)行隨機(jī)縮放并旋轉(zhuǎn)制定角度 PS.建議不要對(duì)文字進(jìn)行縮放與旋轉(zhuǎn),因?yàn)檫@樣圖片可能不正常顯示
/*將文字旋轉(zhuǎn)制定角度*/
Graphics2D g2d_word=(Graphics2D)g;
AffineTransform trans=new AffineTransform();
trans.rotate((45)*3.14/180,15*i+8,7);
/*縮放文字*/
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(); //釋放g所占用的系統(tǒng)資源
ImageIO.write(image,"JPEG",response.getOutputStream()); //輸出圖片
}
}
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();
}
}
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重慶分公司
