这里实现我使用到了struts2模拟一个登录功能来验证java实现的验证码功能。
java实现验证码的步骤：
1、创建randomimagegenerator.java类，该类实现验证码图片的生成
2、创建一个servlet类，randomimageservlet.java，将生成的验证码输出到页面
3、创建一个action类，loginaction.java，控制登录
4、配置struts.xml一个web.xml文件
5、编写页面
具体实现用代码表达
1、创建randomimagegenerator.java类
复制代码 代码如下:
package com.tenghu.code;
import java.awt.color;
import java.awt.font;
import java.awt.graphics2d;
import java.awt.image.bufferedimage;
import java.io.filenotfoundexception;
import java.io.fileoutputstream;
import java.io.ioexception;
import java.io.outputstream;
import java.util.random;
import javax.imageio.imageio;
/**
* 验证码生成类
* @author xiaohu
*
*/
public class randomimagegenerator {
//创建random对象
static random random=new random();
//随机生成包含验证码字符串
public static string random(int num){
//初始化种子
string[] str={"0","1","2","3","4","5","6","7","8","9",
"a","b","c","d","e","f","g","h","i","j",
"k","l","m","n","p","q","r","s","t"};
int number=str.length;
//接收随机字符
string text = "";
//随机产生4个字符的字符串
for(int i=0;i<num;i++){
text+=str[random.nextint(number)];
}
return text;
}
/**
* 随机产生定义的颜色
*
* @return
*/
private static color getrandcolor() {
random random = new random();
color color[] = new color[10];
color[0] = new color(32, 158, 25);
color[1] = new color(218, 42, 19);
color[2] = new color(31, 75, 208);
color[3] = new color(0, 102, 182);
color[4] = new color(171, 0, 85);
return color[random.nextint(5)];
}
/**
* 产生随机字体
*
* @return
*/
private static font getfont() {
random random = new random();
font font[] = new font[5];
font[0] = new font("ravie", font.bold, 30);
font[1] = new font("antique olive compact", font.bold, 30);
font[2] = new font("forte", font.bold, 30);
font[3] = new font("wide latin", font.bold, 30);
font[4] = new font("gill sans ultra bold", font.bold, 30);
return font[random.nextint(5)];
}
/**
* 生成图片
* @throws ioexception
*/
public static void render(string randomstr,outputstream out,int width,int height) throws ioexception{
//在内存中创建图像
bufferedimage bi=new bufferedimage(width, height, bufferedimage.type_byte_indexed);
//获取图形上下文
graphics2d g=(graphics2d) bi.getgraphics();
//话边框
g.setcolor(color.white);
g.fillrect(0, 0, width, height);
g.setfont(getfont());
g.setcolor(color.black);
//画认证码，每个认证码在不同的水平位置
string str1[]=new string[randomstr.length()];
for(int i=0;i<str1.length;i++){
str1[i]=randomstr.substring(i,i+1);
int w=0;
int x=(i+1)%3;
//随机生成验证码字符水平偏移量
if(x==random.nextint(7)){
w=30-random.nextint(7);
}else{
w=30+random.nextint(7);
}
//随机生成颜色
g.setcolor(getrandcolor());
g.drawstring(str1[i], 20*i+10, w);
}
//随机产生干扰点，并用不同的颜色表示，事图像的认证码不易被其他程序探测到
for(int i=0;i<100;i++){
int x=random.nextint(width);
int y=random.nextint(height);
color color=new color(random.nextint(255), random.nextint(255), random.nextint(255));
//随机画各种颜色的线
g.setcolor(color);
g.drawoval(x, y, 0, 0);
}
//画干扰线
for(int i=0;i<15;i++){
int x=random.nextint(width);
int y=random.nextint(height);
int x1=random.nextint(width);
int y1=random.nextint(height);
color color=new color(random.nextint(255), random.nextint(255), random.nextint(255));
//随机画各种颜色线
g.setcolor(color);
g.drawline(x, y, x1, y1);
}
//图像生效
g.dispose();
//输出页面
imageio.write(bi, "jpg", out);
}
public static void main(string[] args) throws filenotfoundexception, ioexception {
//获取随机字符串
string randomstr=random(5);
system.out.println(randomstr);
//生成图片
render(randomstr, new fileoutputstream("d:\\test.jpg"),130,40);
}
}
2、创建randomimageservlet.java
复制代码 代码如下:
package com.tenghu.code.servlet;
import java.io.ioexception;
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 com.tenghu.code.randomimagegenerator;
public class randomimageservlet extends httpservlet {
//图片宽度
int width=0;
//图片高度
int height=0;
//图片上随机字符个数
int randomstrnum=0;
public void destroy() {
}
public void doget(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
dopost(request, response);
}
public void dopost(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
request.setcharacterencoding("utf-8");
//获取httpsession对象
httpsession session=request.getsession();
//获取随机字符串
string randomstr=randomimagegenerator.random(randomstrnum);
if(null!=session){
//设置参数
session.setattribute("randomstr", randomstr);
//设置响应类型,输出图片客户端不缓存
response.setdateheader("expires", 1l);
response.setheader("cache-control", "no-cache, no-store, max-age=0");
response.addheader("pragma", "no-cache");
response.setcontenttype("image/jpeg");
//输出到页面
randomimagegenerator.render(randomstr, response.getoutputstream(), width, height);
}
}
public void init() throws servletexception {
//获取宽度
width=integer.parseint(this.getinitparameter("width"));
//获取高度
height=integer.parseint(this.getinitparameter("height"));
//获取个数
randomstrnum=integer.parseint(this.getinitparameter("num"));
}
}
3、创建loginaction.java类
复制代码 代码如下:
package com.tenghu.code.action;
import java.io.bytearrayinputstream;
import java.io.inputstream;
import com.opensymphony.xwork2.actioncontext;
import com.opensymphony.xwork2.actionsupport;
public class loginaction extends actionsupport{
//用户名
private string username;
//密码
private string password;
//验证码
private string code;
private inputstream inputstream;
public inputstream getresult(){
return inputstream;
}
//成功
public string success() throws exception{
return success;
}
//测试登录
public string testlogin() throws exception{
//获取图片的验证码
string randomstr=(string) actioncontext.getcontext().getsession().get("randomstr");
if(code.trim().equalsignorecase(randomstr)){
if("admin".equals(username.trim())&&"admin".equals(password.trim())){
//成功
inputstream=new bytearrayinputstream("1".getbytes("utf-8"));
}else{
//用户名或密码错误
inputstream=new bytearrayinputstream("2".getbytes("utf-8"));
}
}else{
//验证码错误
inputstream=new bytearrayinputstream("0".getbytes("utf-8"));
}
return "result";
}
public string getusername() {
return username;
}
public void setusername(string username) {
this.username = username;
}
public string getpassword() {
return password;
}
public void setpassword(string password) {
this.password = password;
}
public string getcode() {
return code;
}
public void setcode(string code) {
this.code = code;
}
}
4、配置struts.xml、web.xml文件
复制代码 代码如下:
<?xml version="1.0" encoding="utf-8"?>
<!doctype struts public
"-//apache software foundation//dtd struts configuration 2.3//en"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<package name="installs" extends="struts-default">
<action name="login" class="com.tenghu.code.action.loginaction">
<!-- 登录成功到success.jsp页面 -->
<result name="success">success.jsp</result>
<!-- 登录验证返回的数据 -->
<result name="result" type="stream">
<param name="contenttype">text/html</param>
<param name="inputname">result</param>
</result>
</action>
</package>
</struts>
复制代码 代码如下:
<?xml version="1.0" encoding="utf-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"
xsi:schemalocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<description>this is the description of my j2ee component</description>
<display-name>this is the display name of my j2ee component</display-name>
<servlet-name>randomimageservlet</servlet-name>
<servlet-class>com.tenghu.code.servlet.randomimageservlet</servlet-class>
<!-- 初始化图片宽度 -->
<init-param>
<param-name>width</param-name>
<param-value>130</param-value>
</init-param>
<!-- 初始化图片高度 -->
<init-param>
<param-name>height</param-name>
<param-value>40</param-value>
</init-param>
<!-- 初始化图片随机数个数 -->
<init-param>
<param-name>num</param-name>
<param-value>4</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>randomimageservlet</servlet-name>
<url-pattern>/verification.do</url-pattern>
</servlet-mapping>
<!-- 配置struts核心过滤器 -->
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.strutsprepareandexecutefilter</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
5、编写测试页面
复制代码 代码如下:
<%@ page language="java" import="java.util.*" pageencoding="utf-8"%>
<!doctype html public "-//w3c//dtd html 4.01 transitional//en">
<html>
<head>
<base href="<%=basepath%>">
<title>my jsp 'index.jsp' starting page</title>
<script type="text/javascript" src="js/jquery-1.10.2.min.js"></script>
<script type="text/javascript" src="js/jquery.form.js"></script>
<script type="text/javascript">
$(document).ready(function(){
code.initcode();
//验证输入
function checkinput(){
if($('#username').val()==''){
alert('用户名不能为空！');
return false;
}
if($('#password').val()==''){
alert('密码不能为空！');
return false;
}
if($('#code').val()==''){
alert('验证码不能为空！');
return false;
}
return true;
}
//点击按钮
$('#btn').click(function(){
if(checkinput()==true){
$('#login_request').ajaxsubmit({
url:'login!testlogin',
cache:false,
type:'post',
success:function(data){
if(data==0){
alert('验证码错误！');
//改变验证码
code.initcode();
}else if(data==1){
alert('登录成功！');
//提交到登录成功页面
$('#login_request')[0].submit();
}else if(data==2){
alert('用户名或密码错误！');
//改变验证码
code.initcode();
}
},
error:function(e){
alert('出错了！');
}
});
}
});
});
var code={
//初始化化验证码
initcode:function(){
$("#code_img").attr("src","verification.do?rmd="+new date().gettime())//如果需要点击图片改变图片的内容，则必须添加时间搓
.click(function(){
$(this).attr("src","verification.do?rmd="+new date().gettime());
});
}};
</script>
</head>
<body>
<form action="login!success" id="login_request" method="post">
username:<input type="text" id="username" name="username"/><br/>
password:<input type="password" id="password" name="password"/><br>
verification_code:<input type="text" id="code" name="code"/><img id="code_img" style="position:relative;top:8px;height:25px"><br>
<input type="button" id="btn" value="登录"/>
</form>
</body>
</html>
成功页面就部贴出来了，就是一段文字而已
显示结果：
