在 servlet 中加载 fcl 文件时出错答案

【问题标题】：Error loading fcl file in servlet在 servlet 中加载 fcl 文件时出错
【发布时间】：2015-07-21 15:37:40
【问题描述】：

我有 Java Web 应用程序 JSP/Servlet，它与 jFuzzyLogic 库一起使用，该库使用位于 WEB-INF/rules/rules.fcl 的 rules.fcl 文件。我正在尝试将 rules.fcl 文件加载到 servlet 文件中，但是当我尝试执行应用程序 web 时出现以下错误：

16:28:18,284 ERROR [io.undertow.request] (default task-4) UT005023:    Exception handling request to /fuzzy/InterpretationF: java.lang.NullPointerException
at PackVue.InterpretationF.doGet(InterpretationF.java:74) [classes:]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:687) [jboss-servlet-api_3.1_spec-1.0.0.Final.jar:1.0.0.Final]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) [jboss-servlet-api_3.1_spec-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:61) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:25) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:113) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.security.handlers.AuthenticationCallHandler.handleRequest(AuthenticationCallHandler.java:52) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:45) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:61) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:70) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.security.handlers.SecurityInitialHandler.handleRequest(SecurityInitialHandler.java:76) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:25) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
at  org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:25) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:25) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:240) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:227) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:73) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:146) [undertow-servlet-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:168) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:687) [undertow-core-1.0.0.Final.jar:1.0.0.Final]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_45]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_45]
at java.lang.Thread.run(Thread.java:744) [rt.jar:1.7.0_45]

请有人帮我解决这个问题！谢谢。

【问题讨论】：

你应该显示你用来加载文件的代码。
ServletContext ctx = null; InputStream inputStream = ctx.getResourceAsStream("/WEB-INF/rules/rules.fcl"); boolean v = true; FIS fis = FIS.load(inputStream, v);

标签： java jsp servlets fuzzy-logic jfuzzylogic

【解决方案1】：

你的代码说你犯了一个非常糟糕的业余错误，这是因为ctx 为空。

确保您在 servlet 中使用 init 方法加载所需的资源，可能如下所示。

FIS fis=null;
@Override public void init(ServletConfig config) throws ServletException {
    InputStream is=config.getServletContext().getResourceAsStream("/WEB-INF/rules/rules.fcl");
    fis=FIS.load(is,true);
}

【讨论】：

【解决方案2】：

这对我有用：

    public static InputStream getFile(String fileName) throws FileNotFoundException {
    //where fileName is my file path src/main/resources/tipper.fcl
    InputStream is = new FileInputStream(fileName);
    return is;
}

【讨论】：