ssh项目导入报the import javax.servlet cannot be resolved

时间:2023-01-13 22:57:43

在做javaWeb项目时,我们经常会出现丢失包的情况,如下图所示的错误,我们应该怎么解决呢?

 

根据网上教程向工程中加入tomcat的servlet-api.jar和jsp-api.jar的包

  ssh项目导入报the import javax.servlet cannot be resolved

此时项目确实不会报错了,但是更坑的报错出现了;运行项目发现 

严重: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
    at org.apache.jsp.index_jsp._jspInit(index_jsp.java:23)
    at org.apache.jasper.runtime.HttpJspBase.init(HttpJspBase.java:52)
    at org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:164)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:340)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:861)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:620)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Thread.java:745)


然后百度一顿搜索;查找到的原因是jsp-api.jar包与tomcat下的jsp-api.jar包冲突,要移除冲突的包;然后就去找WEB-INF下面的包,没发现这两个包啊,确实是很奇怪;

后面认真查看项目的结构,问题终于找到了;发现少了 JAVA EE5 Libraries系统包;而servlet-api.jar和jsp-api.jar在JAVA EE5 Libraries包下,直接使用javaee5 library的包即可;

 

解决方法

引入 JAVA EE5 Libraries系统包,并查找.classpath文件中查看是否有servlet-api.jar和jsp-api.jar这两个包的加载配置,如果有的话就删除即可

最重要的一点 一定要clean下项目,不然不起作用。