在Tomcat运行JSP的一个问题

今天在tomcat（7.0.8）上运行一本书的JSP源代码时，出现如下错误： 

 1 org.apache.jasper.JasperException: Unable to compile class for JSP: 
 2 
 3 An error occurred at line: 23 in the generated java file
 4 The method getJspApplicationContext(ServletContext) is undefined for the type JspFactory
 5 
 6 Stacktrace:
 7     org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:95)
 8     org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:330)
 9     org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:457)
10     org.apache.jasper.compiler.Compiler.compile(Compiler.java:367)
11     org.apache.jasper.compiler.Compiler.compile(Compiler.java:345)
12     org.apache.jasper.compiler.Compiler.compile(Compiler.java:332)
13     org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:594)
14     org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:342)
15     org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:391)
16     org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
17     javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
18 
19 

查看Tomcat的Log，发现如下错误：  

 1 SEVERE: Failed to initialize end point associated with ProtocolHandler ["http-apr-8088"]
 2 java.lang.Exception: Socket bind failed: [730048] Only one usage of each socket address (protocol/network address/port) is normally permitted.  
 3     at org.apache.tomcat.util.net.AprEndpoint.bind(AprEndpoint.java:408)
 4     at org.apache.tomcat.util.net.AbstractEndpoint.init(AbstractEndpoint.java:511)
 5     at org.apache.coyote.AbstractProtocolHandler.init(AbstractProtocolHandler.java:345)
 6     at org.apache.catalina.connector.Connector.initInternal(Connector.java:910)
 7     at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:101)
 8     at org.apache.catalina.core.StandardService.initInternal(StandardService.java:559)
 9     at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:101)
10     at org.apache.catalina.core.StandardServer.initInternal(StandardServer.java:778)
11     at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:101)
12     at org.apache.catalina.startup.Catalina.load(Catalina.java:572)
13     at org.apache.catalina.startup.Catalina.load(Catalina.java:595)
14     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
15     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
16     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
17     at java.lang.reflect.Method.invoke(Method.java:597)
18     at org.apache.catalina.startup.Bootstrap.load(Bootstrap.java:263)
19     at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:431)

开始以为是Server的配置有问题，网上搜了一下，发现都说是Tomcat开了多个造成，或者是JSP的code有问题。

但是自己又试了试Tomcat自带的JSP，人家的jsp运行的好好的。

所以觉得Tomcat应该没有什么配置上的问题。

后来查到这本书带的源代码中的build.xml文件，是这样设置的： 

 1   <property environment="env" />
 2   <property name="src" value="WEB-INF/src" />
 3   <property name="classes" value="WEB-INF/classes" />
 4   <property name="lib" value="WEB-INF/lib" /> 
 5   <property name="dist" value="dist" />
 6   
 7   <path id="task.classpath">
 8     <pathelement location="${classes}" />
 9     <pathelement location="${lib}" /> 
10     
11     <!-- Tomcat 5.0.16 Servlet 2.4 API -->
12     <pathelement location="${lib}/servlet-api.jar" />
13     
14     <!-- Tomcat 5.0.16 JSP 2.0 API -->
15     <pathelement location="${lib}/jsp-api.jar" />
16     
17   </path>

这Tomcat的版本比我的要老的多啊。

后来用tomcat的Lib目录下的这两个jar包替换掉之后，就好了。 JSP就可以编译运行了。

总结一下，“Unable to compile class for JSP” 八成和编译用的 “jsp-api.jar”是有关系的。