Simple MVC framework implemented by Servlet3.0

Jar Pack Preparation: Servlet-api-3.0.jar
The project structure is as follows:

annotation mapping, for mapping URL addresses

 /* * file name: Action.java
 * Copyright 2007-2016 517na Tech. Co. Ltd. All rights Reserved. 
 * Description: Action.java
 * Modified by: Peiyu
 * Modified: July 29, 2016
 * Modified: NEW */
 package
com.servlet3.annotation;

Import Java.lang.annotation.ElementType;
Import java.lang.annotation.Retention;
Import Java.lang.annotation.RetentionPolicy;
Import Java.lang.annotation.Target;

@Target ({elementtype.method,elementtype.type})
@Retention (retentionpolicy.runtime) public
@interface Mapping {
    String value ();
}

Actionmodel, for encapsulating action information

/* * File name: Actionmodel.java * Copyright 2007-2016 517na Tech. Co. Ltd. 
 All rights Reserved.

* Description: Actionmodel.java * Modified by: Peiyu * Modified: August 1, 2016 * Modified: NEW */Package com.servlet3.util;
Import java.io.Serializable;

Import Java.lang.reflect.Method;
     /** * @author Peiyu * */public class Actionmodel implements serializable{/** * Add field comments.

    */private static final long serialversionuid = 1L;
    Private String ClassName;
    Private Method method;
    Private Object action;
     /** * Set classname.
    * @return Return ClassName */public String GetClassName () {return className;
     }/** * get classname. * @param className to set ClassName */public void Setclassname (String className) {this.classname = Classna
    Me
     }/** * Set method.
    * @return Return Method */Public method GetMethod () {return method;
     }/** * Gets method. * method to be set for @param method */public voidSetmethod (method) {This.method = method;
     }/** * Set action.
    * @return Return action */public Object getaction () {return action;
     }/** * Gets the action.
    * @param action to set the action */public void setaction (Object action) {this.action = action;
 }
}

myfilter Filter, creating annotations that scan all classes under the specified package when initializing, parsing URLs, creating beans

/* * File name: Myfilter.java * Copyright 2007-2016 517na Tech. Co. Ltd. 
 All rights Reserved.

* Description: Myfilter.java * Modified by: Peiyu * Modified: July 29, 2016 * Modified: NEW */Package com.servlet3.filter;
Import Java.io.File;
Import Java.io.FileInputStream;
Import java.io.IOException;
Import java.io.UnsupportedEncodingException;
Import java.lang.annotation.Annotation;
Import Java.lang.reflect.Method;
Import Java.net.URLDecoder;
Import Java.util.HashMap;

Import Java.util.Map;
Import Javax.servlet.Filter;
Import Javax.servlet.FilterChain;
Import Javax.servlet.FilterConfig;
Import javax.servlet.ServletException;
Import Javax.servlet.ServletRequest;
Import Javax.servlet.ServletResponse;
Import Javax.servlet.annotation.WebFilter;

Import Javax.servlet.http.HttpServletRequest;
Import com.servlet3.annotation.Mapping;
Import com.servlet3.exception.URLException;
Import Com.servlet3.util.ActionModel;

Import com.servlet3.util.CommentedProperties; /** * * @author Peiyu */@WebFilter (filtername = "Myfilter", Urlpatterns = {"/* "}) public class Myfilter implements Filter {@Override public void Destroy () {Syste
    M.out.println ("-----------------------destroy-----------------------"); } @Override public void DoFilter (ServletRequest request, servletresponse response, Filterchain chain) throws Ioexc
        Eption, servletexception {httpservletrequest httpservletrequest = (httpservletrequest) request;
        String uri = Httpservletrequest.getrequesturi ();
        The logical address of the access/myservlet3 String URL = uri.substring (Uri.indexof ("/", 1));
        Httpservletrequest.getrequesturl ();
        System.out.println ("-----------------------doFilter-----------------------");
        Request.setattribute ("url", url);

    Request.getrequestdispatcher ("/myservlet3"). Forward (Request,response); }/** * * *. Gets the package name that is configured in the configuration file to be scanned. Scan annotations based on package name, get URL, create bean instance */@Override public void init (Filterconfig config) throws servletexception {// Getting packages in a configuration filePath Commentedproperties properties = new Commentedproperties ();  /d:/software/apache-tomcat-7.0.59/webapps/servlet3.0/web-inf/classes/scan-package.properties String ClassPath
        = MyFilter.class.getClassLoader (). GetResource (""). GetPath ();
        String Path = ClassPath + "Scan-package.properties";
        System.out.println ("# # #1加载配置文件:" + path);
        try {path = Urldecoder.decode (path, "UTF-8");
        } catch (Unsupportedencodingexception E1) {e1.printstacktrace ();
        } System.out.println ("# # # #2加载配置文件:" + path);
        try {properties.load (new FileInputStream (path), "UTF-8");
        } catch (IOException e) {e.printstacktrace ();
        }//gets to the package path String scanpackage = Properties.getproperty ("Scan-package"). Replace (".", "/"); /*************************** All files under the scan package ***************************************///Get to the class file path = Clas
spath + scanpackage;        map<string, actionmodel> urls = new hashmap<> ();
        File File = new file (path);
        Get action,url information getfileurls (file, URLs);
    Place Action,url information in ServletContext config.getservletcontext (). SetAttribute ("URLs", URLs);
     }/** * Gets the URL. */private void Getfileurls (file file, map<string, actionmodel> URLs) {if (File.isdirectory ()) {///if it is a text
            folder, get files under Folders file[] files = file.listfiles ();
                for (File temp:files) {if (Temp.isdirectory ()) {Getfileurls (temp, URLs);
                } else {Getfileurl (temp, URLs);
        }}} or else {//If it is a file Getfileurl (files, URLs);
     }}/** * Gets the URL to create the action bean.
        */@SuppressWarnings ("rawtypes") private void Getfileurl (File temp, map<string, actionmodel> URLs) {
        String path;
        Path = Temp.getpath (); STring ClassName = path.substring (path.indexof ("com"), Path.lastindexof (".")).
        Replace ("\ \", ".");
            try {Class clazz = Class.forName (className);
            Get class annotations String StartURL = "";
            annotation[] annotations = clazz.getannotations ();
            for (Annotation annotation:annotations) {//if (Annotation instanceof Mapping) {//judgment is Mapping
            StartURL = ((Mapping) annotation). Value (); }//} if (Clazz.isannotationpresent (Mapping.class)) {StartURL = ((Mapping) c
            Lazz.getannotation (Mapping.class)). Value ();
            }//Get annotations on method method[] methods = Clazz.getmethods ();
            Object action=clazz.newinstance (); for (Method method:methods) {if (Method.isannotationpresent (Mapping.class)) {actio
                    Nmodel Actionmodel = new Actionmodel (); Actionmodel.setclassnamE (className);
                    Actionmodel.setmethod (method);
                    Actionmodel.setaction (action);
                    Mapping annotation=method.getannotation (Mapping.class);
                    String key = StartURL + ((Mapping) annotation). Value ();
                    if (Urls.containskey (key)) {throw new Urlexception ("already exists URL:" + key);
                    } else {urls.put (key, Actionmodel);
                }}//annotations = Method.getannotations ();
                for (Annotation annotation:annotations) {//if (Annotation instanceof Mapping) {//judgment is Mapping
                Actionmodel actionmodel=new Actionmodel ();
                Actionmodel.setclassname (ClassName);
                Actionmodel.setmethod (method);
                Actionmodel.setaction (action); String key = StartURL + ((Mapping) annotation). value ();
                if (Urls.containskey (key)) {//throw new Urlexception ("already exists URL:" +key);
                }else {//Urls.put (key, Actionmodel); }//}//}}} catch (Exception e) {e.prints
        Tacktrace ();
 }
    }
}

scan-package.properties Configuring packages that need to be scanned

Scan-package=com.servlet3.controller

Default-accessed servlet, which finds the specified URL address through the servlet

/* * File name: Myservlet3.java * Copyright 2007-2016 517na Tech. Co. Ltd. 
 All rights Reserved.

* Description: Myservlet3.java * Modified by: Peiyu * Modified: July 29, 2016 * Modified: NEW */Package com.servlet3.controller;
Import java.io.IOException;

Import Java.util.Map;
Import javax.servlet.ServletException;
Import Javax.servlet.annotation.WebInitParam;
Import Javax.servlet.annotation.WebServlet;
Import Javax.servlet.http.HttpServlet;
Import Javax.servlet.http.HttpServletRequest;

Import Javax.servlet.http.HttpServletResponse;

Import Com.servlet3.util.ActionModel; /** * Name: The name of the current servlet * urlpatterns: Requested URL * Loadonstartup:tomcat Initialize the servlet at startup * InitParams: Initialize parameter * Name: Parameter name * Value: Parameter value * * @author Peiyu */@WebServlet (name = "MyServlet3", Urlpatterns = {"/myservlet3"}, Loadonstartup = 1, I Nitparams = {@WebInitParam (name = "Name", value = "java"), @WebInitParam (name = "Age", value = "1")}
     public class MyServlet3 extends HttpServlet {/** * add field comments.
    */Private static final long serialversionuid = 1L; @SuppressWarnings ({"Unchecked"}) @Override protected void doget (HttpServletRequest req, HttpServletResponse resp)
        Throws Servletexception, IOException {string url= (string) req.getattribute ("url");
        map<string, actionmodel> urls = (map<string, actionmodel>) Req.getservletcontext (). GetAttribute ("URLs");
        Actionmodel actionmodel=urls.get (URL); if (actionmodel!=null) {try {Object Res=actionmodel.getmethod (). Invoke (Actionmodel.getaction
                (), REQ,RESP); Based on the returned result type, the return value is processed if (res instanceof String) {if ((String) res). StartsWith ("Redire CT: ")) {//...}
                else if ((String) res). StartsWith ("Forward:")) {//...}
            }else{//...}
     } catch (Exception e) {           E.printstacktrace (); }}} @Override protected void DoPost (HttpServletRequest req, HttpServletResponse resp) throws Servle
    Texception, IOException {doget (req, resp);
 }
}

useraction of the test

 /* * file name: Useraction.java
 * Copyright 2007-2016 517na Tech. Co. Ltd. All rights Reserved. 
 * Description: Useraction.java
 * Modified by: Peiyu
 * Modified: July 29, 2016
 * Modified: NEW */
 package
Com.servlet3.controller ;

Import Javax.servlet.http.HttpServletRequest;
Import Javax.servlet.http.HttpServletResponse;

Import com.servlet3.annotation.Mapping;

/**
 * @author     peiyu
 *
/@Mapping (value= "/myservlet3") public
class Useraction {

    @ Mapping (value= "/login") Public
    String Login (httpservletrequest req, HttpServletResponse resp) {
        SYSTEM.OUT.PRINTLN ("--------login-------------");
        return "Redirect:register";
    }
    Register
    @Mapping (value= "/register") Public
    String Register (httpservletrequest req, HttpServletResponse resp) {

        System.out.println ("--------Register-------------");
        return "Redirect:login";
    }
}

Finally, start the server, and access http://localhost:8072/Servlet3.0/myServlet3/login?name=java&age=1 will find the Useraction login method.