first.jsp
<%@ page language="java" pageEncoding="gb2312"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-bean" prefix="bean"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-html" prefix="html"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-logic" prefix="logic"%>
<html>
%>
<head>
<title>JSP for FirstForm form</title>
</head>
<body>
<html:form action="/first" method="post">
添加分类:<html:text property="fl"/><html:errors property="fl"/>
<html:submit/>
</html:form>
<table>
<logic:present name="fls" scope="request">
<logic:iterate id="fl" name="fls" scope="request">
<tr>
<td><bean:write name="fl" property="fl"/></td>
<td><html:link action="/deleteFl.do" paramId="fl" paramName="fl" paramProperty="fl">删除</html:link></td>
</tr>
</logic:iterate>
</logic:present>
</table>
</body>
</html>
FirstA
package com.yourcompany.struts.action;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import com.yourcompany.struts.form.FirstForm;
import dao.FlDao;
import java.util.ArrayList;
import vo.Fl;
public class FirstAction extends Action {
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)throws Exception {
FirstForm firstForm = (FirstForm) form;// TODO Auto-generated method stub
String fl=firstForm.getFl();
fl = new String(fl.getBytes("ISO-8859-1"));
FlDao flDao=new FlDao();
Fl fll=new Fl();
fll.setFl(fl);
flDao.insertFl(fll);
ArrayList fls=flDao.getAllFl();
request.setAttribute("fls",fls);
return new ActionForward("/first.jsp");
}
}我做的JSP是向数据库提交一个东西 然后在本页显示 奇怪的是刚进入页面只显示提交表单 在提交一次后才显示数据库表中的所有内容 为什么啊?
<%@ page language="java" pageEncoding="gb2312"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-bean" prefix="bean"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-html" prefix="html"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-logic" prefix="logic"%>
<html>
%>
<head>
<title>JSP for FirstForm form</title>
</head>
<body>
<html:form action="/first" method="post">
添加分类:<html:text property="fl"/><html:errors property="fl"/>
<html:submit/>
</html:form>
<table>
<logic:present name="fls" scope="request">
<logic:iterate id="fl" name="fls" scope="request">
<tr>
<td><bean:write name="fl" property="fl"/></td>
<td><html:link action="/deleteFl.do" paramId="fl" paramName="fl" paramProperty="fl">删除</html:link></td>
</tr>
</logic:iterate>
</logic:present>
</table>
</body>
</html>
FirstA
package com.yourcompany.struts.action;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import com.yourcompany.struts.form.FirstForm;
import dao.FlDao;
import java.util.ArrayList;
import vo.Fl;
public class FirstAction extends Action {
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)throws Exception {
FirstForm firstForm = (FirstForm) form;// TODO Auto-generated method stub
String fl=firstForm.getFl();
fl = new String(fl.getBytes("ISO-8859-1"));
FlDao flDao=new FlDao();
Fl fll=new Fl();
fll.setFl(fl);
flDao.insertFl(fll);
ArrayList fls=flDao.getAllFl();
request.setAttribute("fls",fls);
return new ActionForward("/first.jsp");
}
}我做的JSP是向数据库提交一个东西 然后在本页显示 奇怪的是刚进入页面只显示提交表单 在提交一次后才显示数据库表中的所有内容 为什么啊?
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初次进入时,Request中的fls肯定是不存在的,所以页面也就不能显示了
com.yourcompany.struts.action.FirstAction.execute(FirstAction.java:25)
FirstAction
package com.yourcompany.struts.action; import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import com.yourcompany.struts.form.FirstForm;
import dao.FlDao;
import java.util.ArrayList;
import vo.Fl;
public class FirstAction extends Action { public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)throws Exception {
FirstForm firstForm = (FirstForm) form;// TODO Auto-generated method stub
String fl=firstForm.getFl();
fl = new String(fl.getBytes("ISO-8859-1"));
FlDao flDao=new FlDao();
Fl fll=new Fl();
fll.setFl(fl);
flDao.insertFl(fll);
ArrayList fls=flDao.getAllFl();
request.setAttribute("fls",fls);
return new ActionForward("/first.jsp");
}
}
fl = new String(fl.getBytes("ISO-8859-1")); // 我认为应该是这一句出异常,因为 fl 可能是Null
FlDao flDao=new FlDao();
Fl fll=new Fl();
fll.setFl(fl);