Analysis of service methods in the servlet life cycle

Problem
Within the service method in Servletlifecycle, there is super.service (request, response); Will execute This.doget (httpservletrequest request, httpservletresponse response);
No Super.service (request, response); This.doget (...) is not executed. How did it come true?

Extrapolate
A subclass, in a method of overwrite, if the method of the parent class is called, another method within the subclass is executed;
In the Overwrite method, if the method of the parent class is not called, another method within the subclass is not executed;

Analysis-----> Symbols are key notes

1  Public classServletlifecycleextendsHttpServlet {2     Private Static Final LongSerialversionuid = 1L;3     4 @Override5      Public voidService (ServletRequest request, servletresponse response)throwsservletexception, IOException {6         //TODO auto-generated Method Stub7         //This.doget (httpservletrequest) request, (HttpServletResponse) response);8         Super. Service (Request, response);//-------------------> Execute the Service (ServletRequest request, Servletresponse Response) method of the parent class9          TenSYSTEM.OUT.PRINTLN ("Processing client requests"); One     } A  -     protected voidDoget (HttpServletRequest request, httpservletresponse response)throwsservletexception, IOException { -         //TODO auto-generated Method Stub theSYSTEM.OUT.PRINTLN ("Process"); -Response.getwriter (). Append ("Served at:"). Append (Request.getcontextpath ()); -     } -  + } -  +  A  at  -  Public Abstract classHttpServletextendsGenericservlet { -  Public voidService (ServletRequest req, servletresponse Res) -     throwsservletexception, IOException { -  - httpservletrequest request; in httpservletresponse response; -  to     Try { +Request =(httpservletrequest) req; -Response =(HttpServletResponse) res; the}Catch(classcastexception e) { *         Throw NewServletexception ("Non-http Request or response"); $     }Panax NotoginsengService (request, response);//-------------------> Overloads of the Parent class's methods perform the service of the parent class (HttpServletRequest request, HttpServletResponse response) method  -     //-------------------> My understanding is that if there are no overloads, there will be a dead loop. Go here and execute the service method of the subclass Servletlifecycle, and the subclass calls the parent class service method, looping the nesting. the } +  A  the protected voidService (HttpServletRequest req, HttpServletResponse resp) +         throwsservletexception, IOException { -  $String method =Req.getmethod (); $  -         if(Method.equals (method_get)) { -             LongLastModified =getlastmodified (req); the             if(LastModified = =-1) { -                 //servlet doesn ' t support if-modified-since, no reasonWuyi                 //To go through further expensive logic theDoget (req, resp);//-------------------> Call doget method of subclass Servletlifecycle -}Else { Wu                 Longifmodifiedsince; -                 Try { AboutIfmodifiedsince =Req.getdateheader (header_ifmodsince); $}Catch(illegalargumentexception iae) { -                     //Invalid Date Header-proceed as if none was set -Ifmodifiedsince =-1; -                 } A                 if(Ifmodifiedsince < (lastmodified/1000 * 1000)) { +                     //If The servlet mod time is later, call Doget () the                     //Round down to the nearest second for a proper compare -                     //A ifmodifiedsince of-1 would always is less $ maybesetlastmodified (resp, lastmodified); the doget (req, resp); the}Else { the Resp.setstatus (httpservletresponse.sc_not_modified); the                 } -             } in  the}Else if(Method.equals (Method_head)) { the             LongLastModified =getlastmodified (req); About maybesetlastmodified (resp, lastmodified); the Dohead (req, resp); the  the}Else if(Method.equals (method_post)) { + doPost (req, resp); -  the}Else if(Method.equals (method_put)) {Bayi DoPut (req, resp); the  the}Else if(Method.equals (Method_delete)) { - DoDelete (req, resp); -  the}Else if(Method.equals (method_options)) { the dooptions (REQ,RESP); the  the}Else if(Method.equals (method_trace)) { - Dotrace (REQ,RESP); the  the}Else { the             //94             //Note that this means NO servlet supports whatever the             //method is requested, anywhere on the this server. the             // the 98String errmsg = lstrings.getstring ("http.method_not_implemented"); Aboutobject[] Errargs =NewObject[1]; -Errargs[0] =method;101ErrMsg =Messageformat.format (errmsg, Errargs);102 103 Resp.senderror (httpservletresponse.sc_not_implemented, errmsg);104         } the     }106 107 108 protected voiddoget (httpservletrequest req, HttpServletResponse resp)109     throwsservletexception, IOException the {111String protocol =Req.getprotocol (); theString msg = lstrings.getstring ("http.method_get_not_supported");113     if(Protocol.endswith ("1.1")) { the Resp.senderror (httpservletresponse.sc_method_not_allowed, msg); the}Else { the Resp.senderror (Httpservletresponse.sc_bad_request, msg);117     }118 }119}

Analysis of service methods in the servlet life cycle