常见异常精.docx

1、常见异常精提示java.lang.UnsupportedClassVersionError: Bad version number in .class fileMyeclipse 使用的JDK和Tomcat使用的JDK版本不一致解决方法：把它们的JDK版本改成一致步骤如下:1.Window - Preferences -Java - compiler中的compiler compliance level对应的下拉菜单中选择JDK版本.2.Window - Preferences -MyEclipse - Servers -Tomcat - Tomcat n.x -JDK中的Tomcat JDK

2、 name下的下拉菜单中选择自身电脑上安装的JDK版本1 、缺少文件上传JAR包 commons-io-1.3.1.jar commons-fileupload-1.2.jarUnable to load bean org.apache.struts2.dispatcher.multipart.MultiPartRequest (jakarta) - unknown location 这个问题是在使用Struts2想做一个上传文件的页面时候Tomcat报出来的错误，详细信息如下：2007-7-19 21:34:09 org.apache.catalina.core.StandardWrappe

3、rValve invoke严重: Servlet.service() for servlet jsp threw exceptionjava.lang.RuntimeException: Unable to load bean org.apache.struts2.dispatcher.multipart.MultiPartRequest (jakarta) - unknown location问题描述:使用Struts2.0.6+Sitemesh2.2.1+Freemark2.3.8的过程中，装饰Action请求的结果页面不会有问题，但是如果装饰直接访问的JSP页面会出现如下错误：java

4、代码 1. javax.servlet.ServletException: Error applying decorator: null 解决方案：经过调试发现是FreeMarkerPageFilter的getLocale方法没有对invocation添加非空判断造成的，错误代码如下：java 代码 1. protected Locale getLocale(ActionInvocation invocation, Configuration configuration) 2. if (invocation.getAction() instanceof LocaleProvider) 3. r

5、eturn (LocaleProvider) invocation.getAction().getLocale(); 4. else 5. return configuration.getLocale(); 6. 7. 改正后的代码如下：java 代码 1. protected Locale getLocale(ActionInvocation invocation, Configuration configuration) 2. if (invocation != null & invocation.getAction() instanceof LocaleProvider) 3. retu

6、rn (LocaleProvider) invocation.getAction().getLocale(); 4. else 5. return configuration.getLocale(); 6. 7. 问题描述:使用Struts2.0.6+Sitemesh2.2.3，我有一个请求/customer/page.action，其结果页面为WEB-INF/jsp/customer/list.jsp，我希望使用main装饰器对返回结果进行装饰，如果配置如下：xml 代码 1. 2. /WEB-INF/jsp/customer/list.jsppattern 3. decorator 则无法

7、成功进行装饰，如果配置如下：xml 代码 1. 2. /*pattern 3. decorator 则可以成功进行装饰。 解决方案:经过调试发现，原来装饰器是根据请求的URI路径匹配需要装饰的页面的，而且此URI路径是相对于上下文路径的，因此针对上述需求正确的配置如下：xml 代码 1. 2. /customer/page.actionpattern 3. decorator 1-:java.lang.NoClassDefFoundError: org/apache/struts2/dojo/views/jsp/ui/HeadTag解决办法：原因缺少了dojo的JAR包，引入即可:struts

8、2-dojo-plugin-2.1.2.jar(The head tag renders required JavaScript code to configure Dojo and is required in order to use any of the tags included in the Dojo plugin.-If you are planning to nest tags from the Dojo plugin, make sure you set parseContent=false, otherwise each request made by the inner t

9、ags will be performed twice.)2-:Unable to load configuration. -bean -jar:file:/F:/Struts2/Struts2/WebRoot/WEB-INF/lib/struts2-core- 2.1.2.jar!/struts-default.xml:46:178Caused by: Unable to load bean: type:org.apache.struts2.dispatcher.multipart.MultiPartRequest class:org.apache.struts2.dispatcher.mu

10、ltipart.JakartaMultiPartRequest -bean -jar:file:/F:/Struts2/Struts2/WebRoot/WEB-INF/lib/struts2-core-2.1.2.jar!/struts-default.xml:46:178Caused by: java.lang.NoClassDefFoundError: org/apache/commons/fileupload/RequestContext解决办法：缺少JAR包，引入commons-fileupload-1.2.1.jar，commons-io-1.3.2.jar即可3-:No tag d

11、atetimepicker defined in tag library imported with prefix s原因版本问题：缺少struts-dojo-plugin JAR包，以及HTML的,中没有使用标签If youre using Struts 2.1.x youre probablymissing thestruts-dojo-plugin. Michals reference below applies to Struts 2.1.xonly. In the lasts versions (since 2.0.9 I guess), all AJAX are in dojo p

12、lugin. So you need toinclude and ( Temp1: Temp2: Temp3: Temp4: ) and call :4-:使用TILES框架If you use the Tiles 2 plugin, check your tiles.xml file(s) to ensure they contain a DOCTYPE.5-:struts2中不支持EL表达式 Convert EL expressions to OGNL Struts2.1 tags do not allow evaluation of JSP EL within their attribu

13、tes.Instead, Struts2 tags evaluate attribute values as OGNL. Allowing bothexpression languages within the same attribute opens major securityvulnerabilities. 6-文件上传过程中取不到文件名和文件类型，即都取到NULL原因：假如页面中file的name=“a”则我们ACTION中设置String aContentType,String aFileName;(此两个其实无所谓，要害是SET方法)setA(File file)(); setAC

14、ontentType(String s);setAFileName(String name) 即格式如下：setXContentType() setXFileName().X代表你给FILE取的NAME名字必须和它相同，固定格式7-严重: Unable to parse requestmons.fileupload.FileUploadBase$SizeLimitExceededException: the request was rejected because its size (8523356) exceeds the configured maximum (2097152)at mon

15、s.fileupload.FileUploadBase$FileItemIteratorImpl.(FileUploadBase.java:914)2008-5-27 17:46:51 mons.CommonsLogger warn警告: Could not find property struts.valueStack2008-5-27 17:46:51 mons.CommonsLogger error严重: the request was rejected because its size (8523356) exceeds the configured maximum (2097152)

16、2008-5-27 17:46:51 mons.CommonsLogger warn警告: Could not find property org.apache.catalina.jsp_file原因：上传文件大小超过预定大小，可以在struts.properties配置文件中设置struts.multipart.maxSize=XXX（XXX为文件大小）8-配置了文件类型限制后，当传错误类型可以拦截不让用户上传该文件，可是跳转的页面却没有跳转到input配置的错误页面，而是返回到了success正确页面。严重: Content-Type not allowed: filedata uploa

17、d_5b01657_11a329d4dcf_8000_00000000.tmp text/plain我的打印输出DEBUG语句内容:File:null FlieName:null type:null即拦截类型成功了java.lang.NullPointerExceptionat java.io.FileInputStream.(FileInputStream.java:103)at com.study.web.util.FileUploadUtil.uploadFile(FileUploadUtil.java:36)at com.study.web.action.UploadFileActio

18、n.execute(UploadFileAction.java:58)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)。2008-5-29 10:59:07 mons.CommonsLogger warn警告: Could not find property org.apache.catalina.jsp_file2008-5-29 10:59:07 mons.CommonsLogger warn警告: Could not find property struts2008-5-29 10:59:07 mons.Comm

19、onsLogger info信息: Removing file filedata tmpupload_5b01657_11a329d4dcf_8000_00000000.tmp原因及解决办法：在该文件上传Action中只配置了FileUploadInterceptor后缺少配置了defaultStack拦截器.在ACTION中配置玩defaultStack拦截器后改错误消失。9-struts.properties中全局配置文件大小，再使用默认FileUploadInterceptor拦截器时候能实现拦截的功能但是后台出现异常。严重: Unable to parse requestmons.fi

20、leupload.FileUploadBase$SizeLimitExceededException: the request was rejected because its size (380) exceeds the configured maximum (10)at mons.fileupload.FileUploadBase$FileItemIteratorImpl.(FileUploadBase.java:914)原因：未知。将全局配置中的限制大小去掉，再重新在ACTION中覆盖配置FileUploadInterceptor拦截器设置大小和文件类型限制，可消除异常。10-多文件上传

21、中，其中一个传被限制的文件如限制aplication/msword(即.doc)文件，答应传文本文件。然而当夹杂在一起传的时候，后台能截获类型错误不可传信息，但是实际却还是上传成功。严重: Content-Type not allowed: filedata upload_4d958287_11a33e76ab9_8000_00000007.tmp application/mswordfile is :tmpupload_4d958287_11a33e76ab9_8000_00000006.tmp fileName:project.txt fileType:text/plainfile is

22、:tmpupload_4d958287_11a33e76ab9_8000_00000007.tmp fileName:application base.doc fileType:application/mswordfile is :tmpupload_4d958287_11a33e76ab9_8000_00000008.tmp fileName:zhongqi-bug.txt fileType:text/plain原因：忘记了继续ActionSupport类。继续后异常消失。11-文件上传异常，不能创建File文件Cannot create type class java.io.File fr

23、om value C:Documents and Settingsadmin桌面OrderReporterServiceImp.java - unknown location原因：忘记了在form表单里将enctype设置成文件上传格式：enctype=multipart/form-data12-当使用限制文件类型和大小的时候抛出空指针异常java.lang.NullPointerExceptiondemo.struts2.action.ValidatFileUploadAction.execute(ValidatFileUploadAction.java:71)sun.reflect.Nat

24、iveMethodAccessorImpl.invoke0(Native Method)原因：在ACTION中配置了fileUpload拦截器后忘记了配置默认拦截器：defautlStack。注重当ACTION中配置自己的拦截器后需要显示配置默认拦截器defaultStack13-在国际化时候抛空指针异常：16:31:12,812 ERROR jsp:253 - Servlet.service() for servlet jsp threw exceptionjava.lang.NullPointerException at java.text.MessageFormat.applyPatte

25、rn(MessageFormat.java:414)at java.text.MessageFormat.(MessageFormat.java:350)at com.opensymphony.xwork2.DefaultTextProvider.getText(DefaultTextProvider.java:70)原因：忘记了在struts.xml中配置国际化常量，或者在struts.properties中配置全局国际化常量 struts.custom.i18n.resources=globeMessage14- struts action的配置文件加载失败：Unable to load

26、configuration. - result - file:/D:/Java/apache-tomcat-5.5.20/webapps/mysts/WEB-INF/classes/test.xml:10:26Caused by: No result type specified for result named error, perhaps the parent package does not specify the result type? - result - file:/D:/Java/apache-tomcat-5.5.20/webapps/mysts/WEB-INF/classes/test.xml:10:26at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.buildResults(XmlConfigurationProvider.java:609) 原因：忘记了继续包struts-default15- struts action 配置文件注重事项：1. 别忘记了继续struts-default默认配置包2.假如配置命名空间，一定要以/开始，例