我一直在研究JSP项目。它使用Struts 1框架。项目很旧，我有很多页面，所以我决定添加一个新页面。我复制了一个包含所有配置，模型动作的现有页面，所以一切都应该没问题。但事实并非如此！
我想先创建一个简单的JSP文件。没有<html:form>，我看到了我的“Hello World”。然后我修改了我的文件：
<% request.setCharacterEncoding("UTF8");%>
<%@page contentType="text/html;charset=UTF-8"%>
<%@page pageEncoding="UTF-8"%>
<%@ taglib uri="/tags/struts-bean" prefix="bean" %>
<%@ taglib uri="/tags/struts-logic" prefix="logic" %>
<%@ taglib uri="/tags/struts-html" prefix="html" %>
<%@ taglib uri="/tags/struts-nested" prefix="nested"%>
<%@ taglib prefix="fa" uri="/WEB-INF/tlds/finearts"%>
<fa:checkLogon/>
<fa:Header/>
<fa:Navigation navigationId="806"/>
<html:form action="/pages/editTexts.do" method="post" onsubmit="return doSubmit(this);" >
</html:form>
<fa:Footer/>
并收到此错误：
org.apache.jasper.JasperException：在第15行处理JSP页面/pages/editTexts.jsp时发生异常
12: <fa:Header/>
13: <fa:Navigation navigationId="806"/>
14:
15: <html:form action="/pages/editTexts.do" method="post" onsubmit="return doSubmit(this);" >
16: </html:form>
17: <fa:Footer/>
Stacktrace:
at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:398)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.displaytag.filter.ResponseOverrideFilter.doFilter(ResponseOverrideFilter.java:125)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at depo.common.filter.EncodeFilter.doFilter(EncodeFilter.java:32)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390)
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:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:595)
Caused by: javax.servlet.ServletException: javax.servlet.jsp.JspException: Cannot retrieve definition for form bean: "EditTextsForm" on action: "/pages/editTexts.do"
at org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:852)
at org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:781)
at org.apache.jsp.pages.editTexts_jsp._jspService(editTexts_jsp.java:104)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
... 24 more
Caused by: javax.servlet.jsp.JspException: Cannot retrieve definition for form bean: "EditTextsForm" on action: "/pages/editTexts.do"
at org.apache.struts.taglib.html.FormTag.lookup(FormTag.java:881)
at org.apache.struts.taglib.html.FormTag.doStartTag(FormTag.java:488)
at org.apache.jsp.pages.editTexts_jsp._jspx_meth_html_005fform_005f0(editTexts_jsp.java:170)
at org.apache.jsp.pages.editTexts_jsp._jspService(editTexts_jsp.java:94)
... 27 more
create connectionjdbc:mysql://localhost:3306/szepmubk? relaxAutoCommit=true&autoReconnect=true&useServerPrepStmts=false&useUnicode=true&characterEn coding=UTF-8&mysqlEncoding=utf8&characterSetResults=UTF-8create connectionjdbc:mysql://localhost:3306/szepmubk? relaxAutoCommit=true&autoReconnect=true&useServerPrepStmts=false&useUnicode=true&characterEn coding=UTF-8&mysqlEncoding=utf8&characterSetResults=UTF-8create connectionjdbc:mysql://localhost:3306/szepmubk? relaxAutoCommit=true&autoReconnect=true&useServerPrepStmts=false&useUnicode=true&characterEn coding=UTF-8&mysqlEncoding=utf8&characterSetResults=UTF-8create connectionjdbc:mysql://localhost:3306/szepmubk? relaxAutoCommit=true&autoReconnect=true&useServerPrepStmts=false&useUnicode=true&characterEn coding=UTF-8&mysqlEncoding=utf8&characterSetResults=UTF-8create connectionjdbc:mysql://localhost:3306/szepmubk? relaxAutoCommit=true&autoReconnect=true&useServerPrepStmts=false&useUnicode=true&characterEn coding=UTF-8&mysqlEncoding=utf8&characterSetResults=UTF-8create connectionjdbc:mysql://localhost:3306/szepmubk? relaxAutoCommit=true&autoReconnect=true&useServerPrepStmts=false&useUnicode=true&characterEn coding=UTF-8&mysqlEncoding=utf8&characterSetResults=UTF-8create connectionjdbc:mysql://localhost:3306/szepmubk? relaxAutoCommit=true&autoReconnect=true&useServerPrepStmts=false&useUnicode=true&characterEn coding=UTF-8&mysqlEncoding=utf8&characterSetResults=UTF-8create connectionjdbc:mysql://localhost:3306/szepmubk? relaxAutoCommit=true&autoReconnect=true&useServerPrepStmts=false&useUnicode=true&characterEn coding=UTF-8&mysqlEncoding=utf8&characterSetResults=UTF-8create connectionjdbc:mysql://localhost:3306/szepmubk? relaxAutoCommit=true&autoReconnect=true&useServerPrepStmts=false&useUnicode=true&characterEn coding=UTF-8&mysqlEncoding=utf8&characterSetResults=UTF-8javax.servlet.ServletException: java.lang.NullPointerException
at org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:520)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:427)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:228)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.displaytag.filter.ResponseOverrideFilter.doFilter(ResponseOverrideFilter.java:125)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at depo.common.filter.EncodeFilter.doFilter(EncodeFilter.java:32)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390)
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:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:595)
Caused by: java.lang.NullPointerException
at depo.finearts.action.EditTextsAction.execute(EditTextsAction.java:35)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:425)
... 26 more
EditTextsForm.java
package depo.finearts.form;
import depo.common.db.DBConnection;
import depo.finearts.*;
import javax.servlet.http.HttpServletRequest;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
public class EditTextsForm extends ActionForm {
DBConnection connection;
User user;
String action;
int id;
@Override
public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) {
ActionErrors errors = new ActionErrors();
if (!action.startsWith("validate") ) return null;
setAction("save");
return errors;
}
@Override
public void reset( ActionMapping mapping, HttpServletRequest request) {
super.reset(mapping, request);
try {
setConnection(new DBConnection());
} catch (Exception ex) {}
action = request.getParameter("action");
if (action == null || "".equals(action)) {
action = "invalid";
}
if (request.getParameterMap().containsKey("id")) {
id = Integer.parseInt(request.getParameter("id"));
user = new User(connection, id);
} else {
user = new User(connection);
}
}
public void save () throws Exception {
getUser().save();
getConnection().getConnection().commit();
}
public DBConnection getConnection() {
return connection;
}
public void setConnection(DBConnection connection) {
this.connection = connection;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public String getAction() {
return action;
}
public void setAction(String action) {
this.action = action;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
}
配置
<action
path="/pages/edit*"
type="depo.finearts.action.Edit{1}Action"
name="Edit{1}Form"
scope="request"
validate="true"
input="/pages/edit{1}.jsp?action=invalid">
<forward name="form" path="/pages/edit{1}.jsp" />
<forward name="view" path="/pages/view{1}.jsp" />
</action>
答案 0 :(得分：5)