本文目錄一覽：
用java怎麼製作驗證碼
原理:
1.隨機生成4個數字 用到了Random類
2.對這4個數字設置字體格式 用 setFont方法
3.改變字體顏色用setColor 然後隨機生成顏色
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();
// 填充的字元串
String str=”ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789″;
//緩存生成的驗證碼
StringBuffer stringbuffer=new StringBuffer();
//隨機生成驗證碼的顏色和字元
for(int i=0;i4;i++)
{ //設置隨機顏色
g.setColor(new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256)));
int index=random.nextInt(62);//這裡的62就是從填充字元段中隨意選取一個位置
String str1=str.substring(index,index+1);
g.drawString(str1, 20*i, 30);//x,y數值設置太小會顯示不出來
stringbuffer.append(str1);
}
//將生成的驗證碼存到伺服器
request.getSession().setAttribute(“checkcode”, stringbuffer.toString());//key和value
//將圖片發送給瀏覽器
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”);// 設置伺服器發送給瀏覽器的編碼方式
request.setCharacterEncoding(“UTF-8”); // 客戶端向伺服器提交的數據的解碼方式
// 獲得用戶提交的數據
String checkcode = request.getParameter(“checkcode”);
System.out.println(checkcode);
// 判斷輸入的驗證碼是不是符合
HttpSession session = request.getSession();// session是存放數據的地方
String str = (String) session.getAttribute(“checkcode”);
if (str != null) {
if (checkcode.compareToIgnoreCase(str) == 0) // 驗證碼忽略大小寫
response.getWriter().println(“驗證碼輸入正確”);
else
response.getWriter().println(“驗證碼輸入錯誤”);
}
else response.getWriter().println(“驗證碼失效”);
// 使用完的驗證碼信息要刪除,返回原頁面再輸一次,驗證碼就失效了
session.removeAttribute(“checkcode”);
}
}
怎麼用Java代碼實現一個驗證碼，求具體實現方法
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’};
// 字元數量
private static final int SIZE = 4;
// 干擾線數量
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;
/**
* 生成隨機驗證碼及圖片
* 返回的數組中，第1個值是驗證碼，第2個值是圖片
*/
public static Object[] createImage() {
StringBuffer sb = new StringBuffer();
// 1.創建空白圖片
BufferedImage image = new BufferedImage(
WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
// 2.獲取圖片畫筆
Graphics graphic = image.getGraphics();
// 3.設置畫筆顏色
graphic.setColor(Color.LIGHT_GRAY);
// 4.繪製矩形背景
graphic.fillRect(0, 0, WIDTH, HEIGHT);
// 5.畫隨機字元
Random ran = new Random();
for (int i = 0; i SIZE; i++) {
// 取隨機字元索引
int n = ran.nextInt(chars.length);
// 設置隨機顏色
graphic.setColor(getRandomColor());
// 設置字體大小
graphic.setFont(new Font(
null, Font.BOLD + Font.ITALIC, FONT_SIZE));
// 畫字元
graphic.drawString(
chars[n] + “”, i * WIDTH / SIZE, HEIGHT / 2);
// 記錄字元
sb.append(chars[n]);
}
// 6.畫干擾線
for (int i = 0; i LINES; i++) {
// 設置隨機顏色
graphic.setColor(getRandomColor());
// 隨機畫線
graphic.drawLine(ran.nextInt(WIDTH), ran.nextInt(HEIGHT),
ran.nextInt(WIDTH), ran.nextInt(HEIGHT));
}
// 7.返回驗證碼和圖片
return new Object[]{sb.toString(), image};
}
/**
* 隨機取色
*/
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();
}
}
怎樣用java實現驗證碼
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); //隨機生成RGB顏色中的r值
g=s+random.nextInt(e-s); //隨機生成RGB顏色中的g值
b=s+random.nextInt(e-s); //隨機生成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);
//指定生成的響應圖片,一定不能缺少這句話,否則錯誤.
response.setContentType(“image/jpeg”);
int width=86,height=22; //指定生成驗證碼的寬度和高度
BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); //創建BufferedImage對象,其作用相當於一圖片
Graphics g=image.getGraphics(); //創建Graphics對象,其作用相當於畫筆
Graphics2D g2d=(Graphics2D)g; //創建Grapchics2D對象
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); //繪製背景
g.setFont(mfont); //設置字體
g.setColor(getRandColor(180,200));
//繪製100條顏色和位置全部為隨機產生的線條,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); //定製線條樣式
Line2D line=new Line2D.Double(x,y,x+x1,y+y1);
g2d.setStroke(bs);
g2d.draw(line); //繪製直線
}
//輸出由英文，數字，和中文隨機組成的驗證文字，具體的組合方式根據生成隨機數確定。
String sRand=””;
String ctmp=””;
int itmp=0;
//制定輸出的驗證碼為四位
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”};
//生成第一位區碼
int r1=random.nextInt(3)+11;
String str_r1=rBase[r1];
//生成第二位區碼
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];
//將生成的機內碼轉換為漢字
byte[] bytes=new byte[2];
//將生成的區碼保存到位元組數組的第一個元素中
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位元組數組的第二個元素中
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);
//將生成的隨機數進行隨機縮放並旋轉制定角度 PS.建議不要對文字進行縮放與旋轉,因為這樣圖片可能不正常顯示
/*將文字旋轉制定角度*/
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所佔用的系統資源
ImageIO.write(image,”JPEG”,response.getOutputStream()); //輸出圖片
}
}
JAVA識別圖片驗證碼
package com.he;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import java.awt.*;
import java.awt.image.*;
import javax.imageio.*;
public class CodeFact
extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
//設置頁面不緩存
response.setHeader(“Pragma”, “No-cache”);
response.setHeader(“Cache-Control”, “no-cache”);
response.setDateHeader(“Expires”, 0);
// 在內存中創建圖象
int width = 60, height = 20;
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
// 獲取圖形上下文
Graphics g = image.getGraphics();
//生成隨機類
Random random = new Random();
// 設定背景色
g.setColor(getRandColor(200, 250));
g.fillRect(0, 0, width, height);
//設定字體
g.setFont(new Font(“Times New Roman”, Font.PLAIN, 18));
//畫邊框
g.setColor(new Color(33,66,99));
g.drawRect(0,0,width-1,height-1);
// 隨機產生155條幹擾線，使圖象中的認證碼不易被其它程序探測到
g.setColor(getRandColor(160, 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);
}
// 取隨機產生的認證碼(4位數字)
String sRand = “”;
for (int i = 0; i 4; i++) {
String rand = String.valueOf(random.nextInt(10));
sRand += rand;
// 將認證碼顯示到圖象中
g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110),
20 + random.nextInt(110))); //調用函數出來的顏色相同，可能是因為種子太接近，所以只能直接生成
g.drawString(rand, 13 * i + 6, 16);
}
// 將認證碼存入SESSION
HttpSession session = request.getSession();
session.setAttribute(“rand”, sRand);
// 圖象生效
g.dispose();
// 輸出圖象到頁面
ImageIO.write(image, “JPEG”, response.getOutputStream());
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
doGet(request, response);
}
//給定範圍獲得隨機顏色
private Color getRandColor(int fc, int bc) {
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);
}
}
你試試！！
原創文章，作者：小藍，如若轉載，請註明出處：https://www.506064.com/zh-tw/n/196338.html
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