当我通过输入地址从 Web 浏览器访问它时，我的 jsp 页面的 _jspInit 函数中出现 NullPointerException。我在网上搜索，他们中的大多数人说这是因为在我的 WEB-INF/lib 文件夹中，有一个 .jar 文件 jsp-api.jar 与 tomcat 容器的 jar 文件相冲突，如java.lang.NullPointerException 在org.apache.jsp.page_jsp._jspInit 在 Tomcat 6 中，但在 Tomcat 7中有效。但是，我检查了 lib 文件夹并没有找到这样的 jar 文件。是什么原因以及如何解决？
这是jsp错误页面：
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: java.lang.NullPointerException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:538)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:370)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
root cause
java.lang.NullPointerException
org.apache.jsp.index_jsp._jspInit(index_jsp.java:25)
org.apache.jasper.runtime.HttpJspBase.init(HttpJspBase.java:52)
org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:164)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:340)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.35 logs.
这是我在tomcat6中我的Web应用程序的lib目录中的jar文件列表：
activation-1.1.jar
antlr-2.7.6.jar
bean-validator.jar
c3p0-0.9.1.jar
cglib-2.2.jar
commons-codec-1.2.jar
commons-codec-1.4.jar
commons-collections-3.1.jar
commons-httpclient-3.1.jar
commons-lang-2.4.jar
commons-logging.jar
commons-logging-1.1.jar
cxf-api-2.2.9.jar
cxf-common-schemas-2.2.9.jar
cxf-common-utilities-2.2.9.jar
cxf-rt-bindings-soap-2.2.9.jar
cxf-rt-bindings-xml-2.2.9.jar
cxf-rt-core-2.2.9.jar
cxf-rt-databinding-jaxb-2.2.9.jar
cxf-rt-frontend-jaxws-2.2.9.jar
cxf-rt-frontend-simple-2.2.9.jar
cxf-rt-transports-http-2.2.9.jar
cxf-rt-ws-addr-2.2.9.jar
cxf-tools-common-2.2.9.jar
dom4j-1.6.1.jar
ehcache-1.2.3.jar
emayclient-v2.jar
epcis-captureclient-0.5.0.jar
epcis-commons-0.5.0.jar
epcis-queryclient-0.5.0.jar
geronimo-annotation_1.0_spec-1.1.1.jar
geronimo-jaxws_2.1_spec-1.0.jar
geronimo-stax-api_1.0_spec-1.0.1.jar
geronimo-ws-metadata_2.0_spec-1.1.2.jar
hibernate3.jar
httpclient-4.1.jar
httpcore-4.1.jar
httpmime-4.1.jar
javassist-3.9.0.GA.jar
javax.annotation.jar
javax.ejb.jar
javax.enterprise.deploy.jar
javax.jms.jar
javax.management.j2ee.jar
javax.persistence.jar
javax.resource.jar
javax.security.auth.message.jar
javax.security.jacc.jar
javax.servlet.jar
javax.servlet.jsp.jar
javax.servlet.jsp.jstl.jar
javax.transaction.jar
jaxb-api-osgi.jar
jaxb-impl-2.2.jar
jboss-cache-1.4.1.GA.jar
jbosscache-core-3.1.0.GA.jar
jdom-2.0.4.jar
jsf-api.jar
jsf-impl.jar
json-20090211.jar
jsr311-api.jar
jstl-impl.jar
jta-1.1.jar
junit.jar
log4j-1.2.14.jar
m4uapi.jar
mail.jar
mysql-connector-java-5.1.21-bin.jar
org.hamcrest.core_1.1.0.v20090501071000.jar
oscache-2.1.jar
proxool-0.8.3.jar
qrgen-1.1.jar
saaj-api-1.3.jar
saaj-impl-1.3.2.jar
slf4j-api-1.5.8.jar
slf4j-log4j12-1.5.8.jar
stax-api-1.0-2.jar
swarmcache-1.0RC2.jar
textmagic-sms-api-1.0.jar
webservices-api-osgi.jar
weld-osgi-bundle.jar
wsdl4j-1.6.2.jar
wstx-asl-3.2.9.jar
xml-resolver-1.2.jar
XmlSchema-1.4.5.jar
zxing-core-1.7.jar
zxing-j2se-1.7.jar