blocks|key|3115590|text|ReCaptcha是你唯一应该使用的验证码，因为它是唯一能让世界变得更好的验证码(将OCR结果改进为旧文本)，几乎有无限的数据库。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3115591|所有其他验证码通常都受到其数据库的限制，或者对这个世界没有任何好处。|3115592|我找到了使用实现验证码的步骤。|style|BOLD|3115593|您可以使用java+here检查在线和离线验证码。|3115594|entityMap|0|LINK|mutability|MUTABLE|url|http://recaptcha.net/|1|http://technoscripts.com/creating-captcha-application-using-java/^0|0|9|0|0|0|6|9|0|A|4|1|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@$A|W|B|X|1|Y]]|C|$]]|$1|D|3|E|5|6|7|Z|8|@]|9|@]|C|$]]|$1|F|3|G|5|6|7|10|8|@$A|11|B|12|H|I]]|9|@]|C|$]]|$1|J|3|K|5|6|7|13|8|@]|9|@$A|14|B|15|1|16]]|C|$]]|$1|L|3|-4|5|6|7|17|8|@]|9|@]|C|$]]]|M|$N|$5|O|P|Q|C|$R|S]]|T|$5|O|P|Q|C|$R|U]]]]

<a href="http://recaptcha.net/" rel="noreferrer">ReCaptcha</a> is the only captcha you should use, because it's the only captcha that makes the world better (improve OCR results to old text), with almost unlimited database.

All other captchas are usually limited by its database, or do nothing good to this world.

EDIT :: I found steps how to implement captcha using recaptcha.

<h2>You can check both Online and Offline captcha using java <a href="http://technoscripts.com/creating-captcha-application-using-java/" rel="noreferrer">here</a></h2>

blocks|key|341666|text|我是SimpleCaptcha的作者。虽然我建议--为了人类的利益--尽可能使用ReCaptcha，但我提供了SimpleCaptcha，因为一些组织有禁止像ReCaptcha这样的库的政策。SimpleCaptcha应该是完全独立的，没有外部依赖:只要您在J2EE容器中，就应该很好用。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|341667|此外，SimpleCaptcha现在可以用于Java1.5或Java6。|341668|entityMap|0|LINK|mutability|MUTABLE|url|http://simplecaptcha.sourceforge.net/^0|2|D|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]]|C|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]]]

I am the author of <a href="http://simplecaptcha.sourceforge.net/" rel="noreferrer">SimpleCaptcha</a>. While I would recommend -- for humanity's sake -- using ReCaptcha where you can, I provided SimpleCaptcha because some organizations have policies which prohibit libraries like ReCaptcha. SimpleCaptcha is meant to be entirely stand-alone, with no external dependencies: as long as you are in a J2EE container, you should be good.

Also, SimpleCaptcha is now available for either Java 1.5 or Java 6.

blocks|key|3115670|text|当ReCaptcha关闭/不可用时会发生什么情况？你的服务会简单地停止吗？当它关闭时，你会简单地停止注册用户吗？即使ReCaptcha没有运行，你也允许用户注册吗？如果是这样的话，这对安全有什么影响？尤其是如果你使用CAPTCHA不仅仅是为了注册，例如重置密码表单，登录表单，...它在没有CAPTCHA组件的情况下是不可接受的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3115671|验证码的Java世界处于一种悲哀的状态，对于我们这些不能接受托管服务的人来说，SimpleCaptcha似乎是最好的解决方案。|3115672|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

What happens when ReCaptcha is down/unavailable? Does your service simply stop? Do you simply stop signing people up when it's down? Do you allow users to sign up even if ReCaptcha isn't running? If so, what are the security implications of this? Especially if you use CAPTCHA for more than just signup, e.g. reset password forms, login forms, ... which would not be acceptable to use without the CAPTCHA component.

The Java world of CAPTCHAs is in a sad state, with SimpleCaptcha seemingly the best solution for those of us out there that cannot accept a hosted service.

blocks|key|346473|text|在recaptcha变得像今天这样流行之前，我创建了http://kaptcha.googlecode.com。它还为您提供了自己托管它的能力，这在某些情况下可能是必要的。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|346474|Kaptcha是一个经过大量修改和更新的SimpleCaptcha版本，支持JDK5/6。|346475|entityMap|0|LINK|mutability|MUTABLE|url|http://kaptcha.googlecode.com/^0|Q|T|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]]|C|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]]]

I created <a href="http://kaptcha.googlecode.com" rel="noreferrer">http://kaptcha.googlecode.com</a> before recaptcha became as popular as it is today. It also offers you the ability to host it yourself, which may be necessary in some situations.

Kaptcha is a heavily modified and updated version of SimpleCaptcha and supports JDK5/6.

blocks|key|343955|text|SimpleCaptcha真的很好用，也很容易使用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|343956|下面是一个如何在JSF2.0中使用SimpleCaptcha的示例(主页上有一个JSP的示例)|343957|请注意，我甚至没有费心在bean中存储captcha值，我只是验证它。|343958|bean：|343959|//+imports+missing+here

@ManagedBean
@SessionScoped
public+class+LoginBean+implements+Serializable
{
++++public+void+validateCaptcha(FacesContext+context,
++++++++++++++++++++++++++++++++UIComponent+componentToValidate,
++++++++++++++++++++++++++++++++Object+value)
++++++++++++throws+ValidatorException
++++{
++++++++HttpSession+session+=+(HttpSession)+context.getExternalContext().getSession(false);
++++++++Captcha+secretcaptcha+=+(Captcha)+session.getAttribute(Captcha.NAME);
++++++++if+(secretcaptcha.isCorrect(value.toString()))
++++++++++++return;

++++++++//+optional:+clear+field
++++++++((HtmlInputText)+componentToValidate).setSubmittedValue("");

++++++++throw+new+ValidatorException(new+FacesMessage("Captcha+does+not+match"));
++++}
}|code-block|syntax|javascript|343960|面孔的相关部分：|343961|<h:form+id="CaptchaForm">
++++Type+this:+ 
++++<h:graphicImage+id="CaptchaImgID"+value="/simpleCaptcha.png"/>+ 
++++<h:inputText+id="CaptchaID"
+++++++++++++++++required="true"
+++++++++++++++++requiredMessage="Captcha+missing"
+++++++++++++++++validator="#{loginBean.validateCaptcha}"
+++++++++++++++++validatorMessage="Captcha+does+not+match"
+++++++++++++++++immediate="true">
++++</h:inputText>
++++ 
++++<h:commandButton+value="Check"/>

++++
++++
++++<h:message+id="CaptchaMsgID"+for="CaptchaID"+style="color:red"+/>
</h:form>|343962|Web.xml的相关部分：|343963|<servlet>
++++<servlet-name>SimpleCaptcha</servlet-name>
++++<servlet-class>nl.captcha.servlet.SimpleCaptchaServlet</servlet-class>
++++<init-param>
++++++++<param-name>captcha-width</param-name>
++++++++<param-value>250</param-value>
++++</init-param>
++++<init-param>
++++++++<param-name>captcha-height</param-name>
++++++++<param-value>75</param-value>
++++</init-param>
</servlet>
<servlet-mapping>
++++<servlet-name>SimpleCaptcha</servlet-name>
++++<url-pattern>/simpleCaptcha.png</url-pattern>
</servlet-mapping>|343964|享受:-)|343965|entityMap^0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Z|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|10|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|11|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|12|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|A|$]]|$1|O|3|P|5|J|7|14|8|@]|9|@]|A|$K|L]]|$1|Q|3|R|5|6|7|15|8|@]|9|@]|A|$]]|$1|S|3|T|5|J|7|16|8|@]|9|@]|A|$K|L]]|$1|U|3|V|5|6|7|17|8|@]|9|@]|A|$]]|$1|W|3|-4|5|6|7|18|8|@]|9|@]|A|$]]]|X|$]]

SimpleCaptcha is really nice and easy to use.
Here's an example how to use SimpleCaptcha with JSF 2.0 (the homepage has an example for JSP)
Note that I'm not even bothering to store the captcha value in the bean, I'm only validating it.
The bean:
<pre class="lang-java prettyprint-override"><code>// imports missing here

@ManagedBean
@SessionScoped
public class LoginBean implements Serializable
{
 public void validateCaptcha(FacesContext context,
 UIComponent componentToValidate,
 Object value)
 throws ValidatorException
 {
 HttpSession session = (HttpSession) context.getExternalContext().getSession(false);
 Captcha secretcaptcha = (Captcha) session.getAttribute(Captcha.NAME);
 if (secretcaptcha.isCorrect(value.toString()))
 return;

 // optional: clear field
 ((HtmlInputText) componentToValidate).setSubmittedValue(&quot;&quot;);

 throw new ValidatorException(new FacesMessage(&quot;Captcha does not match&quot;));
 }
}
</code></pre>
The relevant segment of the facelet:
<pre class="lang-xml prettyprint-override"><code>&lt;h:form id=&quot;CaptchaForm&quot;&gt;
 Type this: &lt;br/&gt;
 &lt;h:graphicImage id=&quot;CaptchaImgID&quot; value=&quot;/simpleCaptcha.png&quot;/&gt; &lt;br/&gt;
 &lt;h:inputText id=&quot;CaptchaID&quot;
 required=&quot;true&quot;
 requiredMessage=&quot;Captcha missing&quot;
 validator=&quot;#{loginBean.validateCaptcha}&quot;
 validatorMessage=&quot;Captcha does not match&quot;
 immediate=&quot;true&quot;&gt;
 &lt;/h:inputText&gt;
 &lt;br/&gt;
 &lt;h:commandButton value=&quot;Check&quot;/&gt;

 &lt;p/&gt;
 &lt;!-- message for the input field --&gt;
 &lt;h:message id=&quot;CaptchaMsgID&quot; for=&quot;CaptchaID&quot; style=&quot;color:red&quot; /&gt;
&lt;/h:form&gt;
</code></pre>
The relevant segment of the web.xml:
<pre class="lang-xml prettyprint-override"><code>&lt;servlet&gt;
 &lt;servlet-name&gt;SimpleCaptcha&lt;/servlet-name&gt;
 &lt;servlet-class&gt;nl.captcha.servlet.SimpleCaptchaServlet&lt;/servlet-class&gt;
 &lt;init-param&gt;
 &lt;param-name&gt;captcha-width&lt;/param-name&gt;
 &lt;param-value&gt;250&lt;/param-value&gt;
 &lt;/init-param&gt;
 &lt;init-param&gt;
 &lt;param-name&gt;captcha-height&lt;/param-name&gt;
 &lt;param-value&gt;75&lt;/param-value&gt;
 &lt;/init-param&gt;
&lt;/servlet&gt;
&lt;servlet-mapping&gt;
 &lt;servlet-name&gt;SimpleCaptcha&lt;/servlet-name&gt;
 &lt;url-pattern&gt;/simpleCaptcha.png&lt;/url-pattern&gt;
&lt;/servlet-mapping&gt;
</code></pre>
Enjoy :-)

blocks|key|3115809|text|如果您希望托管自己的验证码服务，而不是依赖第三方验证码服务(如recaptcha)，Kaptcha是Recaptcha的一个很好的替代方案。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3115810|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Kaptcha is a nice alternative to Recaptcha if you are looking to host your own captcha service instead of relying on a third party captcha service (like recaptcha).

I'm looking for a replacement for JCaptcha, which doesn't seem to be maintained any more, and isn't very good to begin with. The replacement has to integrate nicely with JavaEE webapps.

As I can see it, there are three options:

<ul>
<li>JCaptcha - No longer maintained, crude API</li>
<li>SimpleCaptcha - much nicer API, nicer captchas, but seems to be Java6 only</li>
<li>ReCaptcha - easy to use, uses remote web-service to generate captchas, but not much control over look and feel</li>
</ul>

Has anyone used any others, that they'd recommend?

Recommendations for java captcha libraries

验证码

数据库

容器

Java

我正在寻找JCaptcha的替代品，它似乎不再需要维护，而且一开始就不是很好。替代方案必须与JavaEE with应用程序很好地集成。在我看来，有三种选择：JCaptcha -不再维护，粗糙的验证码-更好的API，更好的验证码，但似乎只有ReCaptcha-易于使用，使用远程web服务生成验证码，但对外观和感觉控制不多有没有人用过他们推荐的其他东西？

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