[英]Infinite Loop while reading a file
這是我試圖從文件中讀取的代碼。 我的文件當前有4行,但是在讀取這些行之后代碼沒有脫離循環。
public class ViewServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
System.out.println("Logging in..");
// retrieving values entered in form
String uname = request.getParameter("uname");
String pwd = (String) request.getParameter("pwd");
if (uname.equals("admin") && pwd.equals("admin")) {
try {
viewDetails();
System.out.println("Redirecting to view page..");
response.sendRedirect("view.jsp");
} catch (Exception e) {
}
}
}
public void viewDetails() throws Exception{
System.out.println("Reading Data..");
BufferedReader input = new BufferedReader(new FileReader("H:/Workspace/teamRecordsApp/WebContent/records.txt"));
String record;
String[] split =new String[5];
ArrayList cuid = new ArrayList();
ArrayList fname = new ArrayList();
ArrayList lname = new ArrayList();
ArrayList mobile = new ArrayList();
ArrayList desk = new ArrayList();
int count = 0;
while((record=input.readLine()) != null){
split = record.split(",");
System.out.println("Record is : "+split[0]+","+split[1]+","+split[2]+","+split[3]+","+split[4]);
cuid.add(split[0]);
fname.add(split[1]);
lname.add(split[2]);
mobile.add(split[3]);
desk.add(split[4]);
count = count+1;
}
input.close();
System.out.println("Reading Done...");
Utils utils = new Utils();
utils.setCuid(cuid);
utils.setFname(fname);
utils.setLname(lname);
utils.setMobile(mobile);
utils.setDesk(desk);
utils.setCount(count);
System.out.println("Total records : "+count);
}
}
*現在添加了整個servlet類。
控制台顯示:
Logging in..
Reading Data..
Record is : 12,e,e,1234567890,1234
Record is : 12,e,e,1234567890,1234
Record is : 12,e,e,1234567890,1234
在文件中添加printStackTrace()之后,下面是我得到的異常。 如@Pshemo所說,最后一行為空,則給出此異常。 我無法通過查看文件並添加printStackTrace來解決問題。 非常感謝@Pshemo和其他人的幫助!
java.lang.ArrayIndexOutOfBoundsException: 1
at ViewServlet.viewDetails(ViewServlet.java:54)
at ViewServlet.doPost(ViewServlet.java:31)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
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.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:127)
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:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Unknown Source)
由於您調用viewDetails();
在try-catch塊中,但您不處理異常(甚至不打印其堆棧跟蹤)
} catch (Exception e) {
//nothing here... :/
}
我認為在"Reading Done..."
按摩之前,您的循環中已引發異常。 異常可能是由許多情況引起的,例如,如果文件中有一些空行,則循環將其讀取為""
並將其拆分為,
這將創建一個元素數組{""}
,然后使用split[1]
獲取IndexOutOfBoundException
。 但這只是可能性之一。 為了確保您的代碼出了什么問題,請添加
e.printStackTrace();
到您的catch (Exception e)
塊。
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