一尘不染

使用JSTL从Spring Controller到JSP访问Map时出错

jsp

我有一个spring控制器,在其中我将返回一个名为“
model”的Map;模型包含一组值,但重要的是还包含一个ArrayList。现在,我将这个Map返回给我的JSP,同时在我的JSP中使用JSTL来获取ArrayList它引发错误。

<c:forEach items="${model.result}" var="data" varStatus="status"> <!-- result is my ArrayList -->
    <c:out value="${data.url}" /> <!-- here url is data inside my result arraylist -->
</c:forEach>

生成的错误是:

root cause

java.lang.NoSuchMethodError: javax.servlet.jsp.PageContext.getELContext()Ljavax/el/ELContext;
    at javax.servlet.jsp.jstl.core.LoopTagSupport.unExposeVariables(LoopTagSupport.java:587)
    at javax.servlet.jsp.jstl.core.LoopTagSupport.doFinally(LoopTagSupport.java:323)
    at jsp_servlet._jsp.__searchsuccess._jsp__tag3(__searchsuccess.java:294)
    at jsp_servlet._jsp.__searchsuccess._jspService(__searchsuccess.java:137)
    at weblogic.servlet.jsp.JspBase.service(JspBase.java:34)

它在Tomcat服务器上可以正常工作,但是当我在Weblogic(9.2)服务器上部署它时会出现错误。我的类路径条目是:

<classpathentry kind="con" path="org.eclipse.jst.j2ee.internal.web.container"/>
    <classpathentry kind="con" path="org.eclipse.jst.j2ee.internal.module.container"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/commons-fileupload-1.1.1.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/commons-io-1.2.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/commons-logging-1.1.1.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/hibernate-validator-4.0.2.GA.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/log4j-1.2.14.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/slf4j-api-1.5.6.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/slf4j-log4j12-1.5.6.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/spring-asm-3.0.3.RELEASE.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/spring-beans-3.0.3.RELEASE.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/spring-context-3.0.3.RELEASE.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/spring-core-3.0.3.RELEASE.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/spring-expression-3.0.3.RELEASE.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/spring-web-3.0.3.RELEASE.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/spring-webmvc-3.0.3.RELEASE.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/validation-api-1.0.0.GA.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/log4j-1.2.9.jar"/>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/servlet-2.3.jar"/>
    <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/jre6">
        <attributes>
            <attribute name="owner.project.facets" value="jst.java"/>
        </attributes>
    </classpathentry>
    <classpathentry kind="lib" path="WebContent/WEB-INF/lib/jstl-1.2.jar"/>
    <classpathentry kind="output" path="WebContent/WEB-INF/classes"/>

更新 :我删除了jstl-1.2.jar,现在出现编译错误:

searchsuccess.jsp:1:5: No tag library could be found with this URI. Possible causes could be that the URI is incorrect, or that there were errors during pa
rsing of the .tld file.
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
    ^----^
searchsuccess.jsp:1:5: No tag library could be found with this URI. Possible causes could be that the URI is incorrect, or that there were errors during pa
rsing of the .tld file.
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
    ^----^

        at weblogic.servlet.jsp.JavelinxJSPStub.compilePage(JavelinxJSPStub.java:298)
        at weblogic.servlet.jsp.JspStub.prepareServlet(JspStub.java:200)
        at weblogic.servlet.jsp.JspStub.prepareServlet(JspStub.java:164)
        at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:235)
        at weblogic.servlet.internal.ServletStubImpl.onAddToMapException(ServletStubImpl.java:394)

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2020-06-08

共1个答案

一尘不染

根据堆栈跟踪,

java.lang.NoSuchMethodError: javax.servlet.jsp.PageContext.getELContext()Ljavax/el/ELContext;
    at javax.servlet.jsp.jstl.core.LoopTagSupport.unExposeVariables(LoopTagSupport.java:587)

JSTL
<c:forEach>标签期望使用该方法PageContext#getELContext()。此方法在JSP
2.1中引入。因此,此异常表明您正在使用JSTL 1.2,而您的容器不支持JSP 2.1,或者您已使用不支持JSP
2.1的容器的servlet容器特定的JSP库乱码了运行时类路径。运行时类路径涵盖了Webapp的/WEB-INF/lib文件夹以及Java
JRE/lib和的JRE/lib/ext文件夹。

你应该 永远 把servletcontainer特定的库中的文件夹,如jsp-api.jarservlet-api.jarel- api.jarj2ee.jarjavaee.jar,etc..etc
..这些文件,你通常看到/lib的servletcontainer本身的文件夹中。例如Tomcat/lib。它使您的Web应用无法移植到目标servlet容器。在那里你运行该web应用程序的目标servletcontainer有这些库
。如果您这样做是为了克服JSP /
Servlet包上的编译错误,那么您应该以不同的方式解决它。


更新 :根据您的更新,您正在使用Weblogic 9.2,它是Servlet 2.4 / JSP 2.0容器。它根本不支持JSP 2.1 /
JSTL 1.2。您需要删除JSTL 1.2库。如果我没记错的话,Weblogic已经附带了JSTL 1.1。否则,您需要自己将其包括在类路径(/WEB-INF/lib文件夹)中。

2020-06-08