Tôi đã mã servlet sauLớp học của tôi không phải là một lỗi servlet
public void doPost(HttpServletRequest request, HttpServletResponse response){
Backup bup = new Backup();
bup.doBackup();
response.setContentType("text/html");
PrintWriter out;
try {
out = response.getWriter();
out.println("You backed up your data - well hopefully");
out.flush();
out.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
Và stack trace sau
javax.servlet.ServletException: Lớp view.BackupServlet không phải là một Servlet org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:102) org.apache.catalina.connector.CoyoteAdapter.service (CoyoteAdapter.java:293) org.apache.coyote.http11.Http11Processor.process (Http11Proc essor.java:849) org.apache.coyote.http11.Http11Protocol $ Http11ConnectionHandler.process (Http11Protocol.java WEBC83) org.apache.tomcat.util.net.JIoEndpoint $ Worker.run (JIoEndpoint.java:454) java.lang.Thread.run (Thread.java:619)
nguyên nhân gốc rễ
java.lang.ClassCastException: view.BackupServlet không thể được đúc để javax.servlet.Servlet org.apache. catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:102) org.apache.catalina.connector.CoyoteAdapter.service (CoyoteAdapter.java:293) org.apache.coyote .http11.Http11Processor.process (Http11Processor.java:849) org.apache.coyote.http11.Http11Protocol $ Http11ConnectionHandler.process (Http11Protocol.java WEBC83) org.apache.tomcat.util.net.JIoEndpoint $ Worker.run (JIoEndpoint.java:454) java.lang.Thread.run (Thread.java:619)
và web.xml là
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-<br>app_2_4.xsd">
<display-name>Backup</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<servlet>
<description>BackupServlet</description>
<display-name>BackupServlet</display-name>
<servlet-name>BackupServlet</servlet-name><br>
<servlet-class>view.BackupServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>BackupServlet</servlet-name>
<url-pattern>/BackupServlet</url-pattern>
</servlet-mapping>
</web-app>`