报错org.apache.jasper.JasperException: java.lang.NullPointerException

最新推荐文章于 2024-09-13 13:43:59 发布

baidu_33416654

最新推荐文章于 2024-09-13 13:43:59 发布

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本文链接：https://blog.youkuaiyun.com/baidu_33416654/article/details/79898876

博主在运行JSP页面时遇到错误，主要问题是页面无法正确显示搜索结果。代码中使用了Servlet进行数据处理，并将数据传递给JSP页面展示。疑似问题出现在数据传递或页面解析的过程中。

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运行jsp页面，出现以下错误。很急，搞了两天，真的是没办法了！！！希望有大神可以看一下！！！

jar包我是这样的，不知道jar包应该放在web—INF下面的lib还是另建一个？我这里另建了一个，都试了试。应该不存在重复问题。

然后报错有一行，应该代码有问题，然后去找

org.apache.jsp.result_jsp._jspService(result_jsp.java:91)

91行应该没错吧还是下面if代码有错？？没搞懂

下面贴源码

result.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="java.util.*" %>
<%@ page import="servlet.Docs" %>
<%
String query=(String)request.getAttribute("query");
List<Docs> list = new ArrayList<Docs>();
list=(List<Docs>)request.getAttribute("docList");
int totalDocs=(Integer)request.getAttribute("totalDocs");

double time=Double.parseDouble(request.getAttribute("time").toString());
int pageNow=(Integer)request.getAttribute("pageNow");
int pageCount=(Integer)request.getAttribute("pageCount");
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<link rel="stylesheet" href="css/main.css">
<title>搜索结果</title>
<script type="text/javascript">
window.onload=function(){
document.getElementById("query").value ="<%=query%>";
}
</script>
</head>
<body>
<div class="nav">
<div class="nav_left">
<a href="index.jsp"><img alt="logo" src="img/LOGO.png"></a>
</div>
<div class="nav_right">
<div class="nav_form">
<form action="search" method="get">
<input id="query" type="text" name="query" value="<%=query%>">
<input type="submit" value=" 搜索 "><br />
</form>
</div>
</div>
</div>

<div class="docsMain">
<h4>
共搜到<span class="docsNum"><%=totalDocs%></span>个结果|用时<span
class="newsnum"><%=time%></span>秒
</h4>
<%
if (list.size() > 0) {
Iterator<Docs> iter = list.iterator();
Docs docs;
while (iter.hasNext()) {
docs = iter.next();

<div class="item">
<h4>
<a href="<%=docs.getLink()%> " target="_blank"><%=docs.getTitle()%></a>
</h4>
<p>
<%=docs.getContent().length() > 300 ? docs.getContent().substring(0, 300) : docs.getContent()%>
</p>
<p><a href="<%=docs.getLink()%>" target="_blank"><%=docs.getLink()%></a></p>
<p>----------------------------------------------------------</p>
</div>
<%
}
}
%>
</div>

<div class="paging">
<ul>
<li><a href="search?query=<%=query%>&&pageNow=1">首页</a></li>

<%
if (pageNow !=1){
%>
<li><a href="search?query=<%=query%>&&pageNow=<%=pageNow - 1%>">上一页</a></li>
<%
}
%>

<%
for (int i = 1; i <= pageCount; i++) {
%>
<li><a href="search?query=<%=query%>&&pageNow=<%=i%>"><%=i%></a></li>
<%
}
%>
<%
if (pageNow != pageCount){
%>
<li><a href="search?query=<%=query%>&&pageNow=<%=pageNow+1%>">下一页</a></li>
<li><a href="search?query=<%=query%>&&pageNow=<%=pageCount%>">末页</a></li>
<%
}
%>
</ul>
<hr>
</div>

<div class="footerinfo">
<p> </p>
</div>

</body>

</html>

SearchServlet .java

public class SearchServlet extends HttpServlet {

private static final long serialVersionUID = 1L;
private static int totalDocs=0;
private static final int PAGE_SIZE=10;
private int pageCount=1;
private int rowCount=1;
private int pageNow=1;
private static String searchpath="F:\\index";

public void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException{
String query=request.getParameter("query");
System.out.println("查询 " + query);

long starTime=System.currentTimeMillis();

if(!"".equals(query)&&query!=null){
ArrayList<Docs> docList=getSearch(query);

String temp_pageNow=request.getParameter("pagNow");
if(temp_pageNow!=null){
pageNow=Integer.parseInt(temp_pageNow);

}
rowCount=totalDocs;
pageCount=(rowCount-1)/PAGE_SIZE+1;

List<Docs> pagelist=docList.subList(PAGE_SIZE*(pageNow-1), PAGE_SIZE*pageNow<rowCount?PAGE_SIZE*pageNow:rowCount);

if(docList.size()!=0){
request.setAttribute("query", query);
request.setAttribute("docList", pagelist);
request.setAttribute("totalDocs", totalDocs);
long endTime=System.currentTimeMillis();
long Time = endTime-starTime;
request.setAttribute("time",(double)Time/1000);
request.setAttribute("pageNow", pageNow);
request.setAttribute("pageCount", pageCount);
//request.setAttribute("highlighter", highlighter);

request.getRequestDispatcher("result.jsp").forward(request, response);

}else {
request.getRequestDispatcher("error.jsp").forward(request, response);
}

}

}
private static ArrayList<Docs> getSearch(String keyword){
ArrayList<Docs> docList=new ArrayList<Docs>();
DirectoryReader directoryReader=null;

try {
Directory directory=FSDirectory.open(new File(searchpath));
directoryReader=DirectoryReader.open(directory);
IndexSearcher indexSearcher=new IndexSearcher(directoryReader);

Analyzer analyzer=new IKAnalyzer();
QueryParser queryParser=new QueryParser(Version.LUCENE_46, "content",analyzer );
Query query=queryParser.parse(keyword);

TopDocs topDocs=indexSearcher.search(query, 500);
totalDocs=topDocs.totalHits;
System.out.println("查找到的文档共有：" + totalDocs);

ScoreDoc[] scoreDocs=topDocs.scoreDocs;
for(int i=0;i<topDocs.scoreDocs.length;i++){

Document document=indexSearcher.doc(scoreDocs[i].doc);

System.out.println("[" + i + "]" + document.get("title"));
System.out.println(document.get("link"));
System.out.println("score:" + scoreDocs[i].score);
Docs docs = new Docs(document.get("title"), document.get("link"),
document.get("content"), totalDocs);
docList.add(docs);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return docList;
}

protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException{
doPost(request, response);
}
//测试
public static void main(String[] args) {
ArrayList<Docs> docList=new ArrayList<Docs>();
docList=(ArrayList<Docs>)getSearch("帮助");

}

测试有结果，但jsp就是打不开，还是数据没传入jsp？？