如何扩展不在项目中的类

Question

我正在尝试为xwiki编写一个custom authentication类。

我有一个在其中编写了身份验证机制的项目，如果有人尝试访问xwiki，我希望它使用xwiki自定义身份验证将他们重定向到我的项目的登录页面。

我正在尝试从我的项目和xwiki中分离出一个类，将其打包为jar，并将其放入xwiki项目的xwiki WEB-INF/lib文件夹中，因为这就是xwiki自定义身份验证的说明。

问题是，我需要编写的类导入了一些xwiki类。如果我用这些导入编写一个单独的类，它将不能正确编译。

如果一个单独的类需要放到xwiki的WEB-INF/lib文件夹中，我该如何创建一个扩展某些xwiki类的类呢？

这是一个有人发布https://www.box.com/shared/9kamt5d9c5的例子。

简单的例子

package my.xwiki.custom.authentication;

import java.io.*;
import com.xpn.xwiki.XWikiContext;
import com.xpn.xwiki.XWikiException;
import com.xpn.xwiki.user.api.XWikiUser;
import com.xpn.xwiki.user.impl.xiki.XWikiAuthServiceImpl;


public class XWikiSSOImpl extends XWikiAuthServiceImpl {

    @Override
    public XWikiUser checkAuth(XWikiContext context) throws XWikiException {
        System.out.println("we actually in checkAuth?");
    }
}

当我将jar文件添加到我的xwiki并运行它时，我得到以下错误：

Detailed information:

    Error number 0 in 11: Uncaught exception
Wrapped Exception: Unresolved compilation problems: 
    The import com.xpn cannot be resolved
    The import com.xpn cannot be resolved
    The import com.xpn cannot be resolved
    The import com.xpn cannot be resolved
    XWikiAuthServiceImpl cannot be resolved to a type
    XWikiUser cannot be resolved to a type
    XWikiContext cannot be resolved to a type
    XWikiException cannot be resolved to a type

com.xpn.xwiki.XWikiException: Error number 0 in 11: Uncaught exception
Wrapped Exception: Unresolved compilation problems: 
    The import com.xpn cannot be resolved
    The import com.xpn cannot be resolved
    The import com.xpn cannot be resolved
    The import com.xpn cannot be resolved
    XWikiAuthServiceImpl cannot be resolved to a type
    XWikiUser cannot be resolved to a type
    XWikiContext cannot be resolved to a type
    XWikiException cannot be resolved to a type

    at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:254)
    at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:116)
    at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
    at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
    at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
    at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:120)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.xwiki.wysiwyg.server.filter.ConversionFilter.doFilter(ConversionFilter.java:144)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at com.xpn.xwiki.plugin.webdav.XWikiDavFilter.doFilter(XWikiDavFilter.java:66)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.xwiki.container.servlet.filters.internal.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:208)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.xwiki.container.servlet.filters.internal.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:111)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.Error: Unresolved compilation problems: 
    The import com.xpn cannot be resolved
    The import com.xpn cannot be resolved
    The import com.xpn cannot be resolved
    The import com.xpn cannot be resolved
    XWikiAuthServiceImpl cannot be resolved to a type
    XWikiUser cannot be resolved to a type
    XWikiContext cannot be resolved to a type
    XWikiException cannot be resolved to a type

    at my.xwiki.custom.authentication.XWikiSSOImpl <init>(XWikiSSOImpl.java:4)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at java.lang.Class.newInstance0(Class.java:355)
    at java.lang.Class.newInstance(Class.java:308)
    at com.xpn.xwiki.XWiki.getAuthService(XWiki.java:5288)
    at com.xpn.xwiki.XWiki.checkAuth(XWiki.java:4090)
    at com.xpn.xwiki.user.impl.xwiki.XWikiRightServiceImpl.checkAccess(XWikiRightServiceImpl.java:205)
    at com.xpn.xwiki.XWiki.checkAccess(XWiki.java:4103)
    at com.xpn.xwiki.XWiki.prepareDocuments(XWiki.java:5128)
    at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:179)
    ... 34 more

Answer 1

根据提供的链接，您似乎没有遗漏任何导入，并且假设您没有任何明显的语法错误，那么它将指向您的开发环境。典型的解决方案是使用包的路径设置CLASSPATH变量，但根据我的经验，这很容易出错。

如果您使用的是Eclipse，请右键单击您的项目名称并选择属性。在属性对话框中，单击左侧的“Java Build Path”。在“Java Build Path”属性中，单击Libraries选项卡。你想点击'Add an External Jar...‘按钮，您将在其中指定xwiki jar的路径。

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Answer 2

要编译一个类，编译器需要所有引用类(包括超类)的定义。它既可以使用已经编译的类(作为.class文件或从JAR文件)，也可以从源代码编译这些类。因为您不想编译xwiki类，所以需要编译前者。

因此，您需要将包含这些类的jar文件添加到类路径中。如何做到这一点取决于您如何调用编译器或使用哪种IDE。使用eclipse，您可以右键单击项目-> Build Path -> Add External Archives。对于javac，您可以使用-cp选项。