Java 在JSP中从外部项目导入类

在eclipse中，我试图将类从外部项目A导入另一个项目B的JSP页面

我在项目B中创建了一个类，在该类中我调用了一些方法，并且一切似乎都运行良好：没有错误，结果是一致的

但当我在项目B中导入JSP时，如下所示：

<%@page import="com.project_A_package.*" %>

在第二个场景中，我甚至在JSP中调用了我在项目B中创建的类，该类成功地从项目a中提取了结果，这次我得到了这个错误（顺便问一句，“com/project\u a\u package/project\u a\u class”正常吗？：

需要做什么来修复此错误？ 或者，为了能够在项目B中调用，项目A中需要调整哪些内容

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非常感谢您的帮助。

尝试将引用的项目A导出为Jar。 完成后，将此Jar以及A使用的所有其他Jar添加到webapp B的构建路径和B的部署程序集中

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希望这对你有用，而且现在回答还不太晚

您是否将项目B添加为src？您的意思是在项目B中：构建路径>源代码>项目B/src？是的，有很多。类文件似乎在那里

<%= Project_A_Class.project_A_static_method() %>

Project_A_Class.cannot be resolved to a type

Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:568)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:455)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)



root cause 
javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/project_A_package/Project_A_Class
    org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:912)
    org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:841)
    org.apache.jsp.project_B_jsp._jspService(project_B_jsp.java:82)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)



root cause 
java.lang.NoClassDefFoundError: com/project_A_package/Project_A_Class
    com.project_B_package.Project_B_Class.startExternal(Project_B_Class.java:7)
    org.apache.jsp.project_B_jsp._jspService(project_B_jsp.java:73)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)



root cause 
java.lang.ClassNotFoundException: com.project_A_package.Project_A_Class
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1702)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1547)
    com.project_B_package.Project_B_Class.startExternal(Project_B_Class.java:7)
    org.apache.jsp.project_B_jsp._jspService(project_B_jsp.java:73)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)