我正在使用 Struts 创建 HelloWorld 示例并获取异常。
索引.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html"%>
<html:form>
Name : <html:text property="name"></html:text>
<html:submit value="Click"></html:submit>
</html:form>
网络.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
id="WebApp_ID" version="2.5">
<display-name>HelloWorld</display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>actionservlet</servlet-name>
<servlet-class>org.apache.struts.actions.ActionServlet</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>actionservlet</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
</web-app>
HelloFormBackup.java
public class HelloFormBackup extends ActionForm{
private String name;
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
@Override
public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) {
ActionErrors ae = new ActionErrors();
if(name.equals("")){
ae.add("name", new ActionMessage("msg"));
}
return ae;
}
}
消息.属性
msg=<font color='red'> name is required.... </font>
HelloController.java
public class HelloController extends Action {
@Override
public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request,
HttpServletResponse response) throws Exception {
String name = request.getParameter("name");
request.setAttribute("result", "hello...."+name);
return mapping.findForward("success");
}
}
成功.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%= request.getAttribute("result") %>
当我使用 Tomcat 6 时出现异常
org.apache.jasper.JasperException: java.lang.NullPointerException: Module 'null' not found.
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:502)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:430)
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:723)
root cause
java.lang.NullPointerException: Module 'null' not found.
org.apache.struts.taglib.TagUtils.getModuleConfig(TagUtils.java:755)
org.apache.struts.taglib.TagUtils.getModuleConfig(TagUtils.java:735)
org.apache.struts.taglib.html.FormTag.lookup(FormTag.java:818)
org.apache.struts.taglib.html.FormTag.doStartTag(FormTag.java:488)
org.apache.jsp.index_jsp._jspx_meth_html_005fform_005f0(index_jsp.java:106)
org.apache.jsp.index_jsp._jspService(index_jsp.java:76)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
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:723)
当我使用 Tomcat 7 时遇到异常
org.apache.jasper.JasperException: An exception occurred processing JSP page /index.jsp at line 6
3: <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
4: <%@ taglib uri="http://struts.apache.org/tags-html" prefix="html"%>
5:
6: <html:form>
7: Name : <html:text property="name"></html:text>
8: <html:submit value="Click"></html:submit>
9:
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:568)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470)
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.NullPointerException: Module 'null' not found.
org.apache.struts.taglib.TagUtils.getModuleConfig(TagUtils.java:755)
org.apache.struts.taglib.TagUtils.getModuleConfig(TagUtils.java:735)
org.apache.struts.taglib.html.FormTag.lookup(FormTag.java:818)
org.apache.struts.taglib.html.FormTag.doStartTag(FormTag.java:488)
org.apache.jsp.index_jsp._jspx_meth_html_005fform_005f0(index_jsp.java:115)
org.apache.jsp.index_jsp._jspService(index_jsp.java:85)
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)
最佳答案
看来 jsp 引擎没有找到选项卡库。根据您使用的 struts 版本，您需要定义
<tablib-uri>
<tablib-location>
在 web.xml 中或将 struts-tablib.jar 正确地放在您的项目目录中。请参阅此链接 http://www.mkyong.com/struts/configure-the-struts-tag-libraries/
关于java - org.apache.jasper.JasperException : java. lang.NullPointerException:找不到模块 'null'，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32662870/