SPRINGMVC Framework Implementation

The SPRINGMVC framework is a spring implementation based on the MVC design pattern, which focuses on three core functions 1 Jump 2 IOC 3 AOP (temporarily not implemented)

Manual writing Springmvc Framework, through annotations to achieve the jump and IOC two core functions, the project structure is as follows:

Create annotations separately @controller

Package com.hongsen.annotation; @Target (Elementtype.type) @Retention (retentionpolicy.runtime) @Documentedpublic @ Interface Controller {    String value ();}

Creating @requestmapping Annotations

Package com.hongsen.annotation; @Target ({elementtype.method,elementtype.type}) @Retention (retentionpolicy.runtime ) @Documentedpublic @interface requestmapping {    String value ();}

Creating @resource Annotations

Package Com.hongsen.annotation, @Target (Elementtype.field) @Retention (retentionpolicy.runtime) public @interface Resource {    String value ();}

Creating @service Annotations

Package com.hongsen.annotation; @Target (Elementtype.type) @Retention (retentionpolicy.runtime) @Documentedpublic @ Interface Service {    String value ();}

Create a servlet with the following code:

Package com.hongsen.servlet;/** * SPRINGMVC function * <p> * 1 Jump * 2 IOC * 3 AOP * * @author Wanghongsen 2018.07.27 */pub    Lic class Dispatcherservlet extends HttpServlet {private static final long serialversionuid = 1L;    Private list<string> classlist = new arraylist<> ();    Private map<string, object> beaninstancemap = new hashmap<> ();    Private map<string, method> urlhandlermap = new hashmap<> ();     /** * Servlet Initialization method * 1 Scan Scan Package path * 2 constructs all class collections (list<string>) * 3 constructs all Bean instance collections (beanname-> beans) * 4 constructs all requests handler jump (URI-and method) */public void init () throws Servletexception {System.out.println ("        Init () Start ");        String Scanbasepath = "Com.hongsen";        Scan (Scanbasepath);        Initbeaninstance ();        IOC ();    Initurlhandlermap (); private void Scan (String scanbasepath) {URL url = this.getclass (). GetResource ("/" + Scanbasepath.replace (".")        , "/")); String BasefIlepath = Url.getfile ();        File Basefile = new file (Basefilepath);        string[] subfilepaths = Basefile.list (); for (String subfilepath:subfilepaths! = null? subfilepaths:new string[0]) {File Subfile = new File (basefi            Lepath + Subfilepath);            if (Subfile.isdirectory ()) {Scan (Scanbasepath + "." + Subfilepath);            } else {Classlist.add (Scanbasepath + "." + Subfilepath); }        }    }
    private void Initbeaninstance () {for (String beanname:classlist) {try {Beanname                = Beanname.replace (". Class", "");                Class Beanclass = Class.forName (beanname); try {if (beanclass.isannotationpresent (Controller.class)) {Controller controll                        ER = (Controller) beanclass.getannotation (Controller.class);                    Beaninstancemap.put (Controller.value (), beanclass.newinstance ()); } else if (Beanclass.isannotationpresent (Service.class)) {Service service = (service) beanclass.ge                        Tannotation (Service.class);                    Beaninstancemap.put (Service.value (), beanclass.newinstance ()); }} catch (Instantiationexception |                Illegalaccessexception e) {e.printstacktrace ();      }} catch (ClassNotFoundException e) {e.printstacktrace ();      }}} private void IOC () {for (String beanname:classlist) {try {b                Eanname = Beanname.replace (". Class", "");                Class Beanclass = Class.forName (beanname);                field[] fields = Beanclass.getdeclaredfields (); for (Field field:fields) {if (Field.isannotationpresent (Resource.class)) {Re                        SOURCE resource = Field.getannotation (Resource.class);                        String val = Resource.value ();                            try {field.setaccessible (true);                            Service service = (service) beanclass.getannotation (Service.class); if (service! = null) {Field.set (Beaninstancemap.get (Service.value ()), Beaninstancemap.get (                            val)); } else {Controller Controller = (Controller) beanclass.getannotation (ControlLer.class); if (Controller = null) {Field.set (Beaninstancemap.get (Controller.value ()), Beaninstan                                Cemap.get (Val)); }}} catch (Illegalaccessexception e) {E.PR                        Intstacktrace (); }}}} catch (ClassNotFoundException e) {e.printstacktrace ()            ;                }}} private void Initurlhandlermap () {for (String beanname:classlist) {try {                Beanname = Beanname.replace (". Class", "");                Class Beanclass = Class.forName (beanname);  if (Beanclass.isannotationpresent (Requestmapping.class)) {requestmapping Basereqmap = (requestmapping)                    Beanclass.getannotation (Requestmapping.class); if (basereqmap! = null) {StringRequestbaseurl = Basereqmap.value ();                        Method[] methods = Beanclass.getmethods (); for (Method method:methods) {requestmapping Reqmap = method.getannotation (requestmapping.cla                            SS);                            if (reqmap! = null) {urlhandlermap.put (Requestbaseurl + reqmap.value (), method); }}}}} catch (Classnotfoundexcep            tion e) {e.printstacktrace (); }}} protected void DoPost (HttpServletRequest request, httpservletresponse response) throws Javax.servlet.Se    Rvletexception, IOException {doget (request, response); } protected void Doget (HttpServletRequest request, httpservletresponse response) throws Javax.servlet.ServletException        , IOException {String uri = Request.getrequesturi (); String ContextPath = Request.getcontextpath();        String Requesturl = Uri.replace (ContextPath, "");        method = Urlhandlermap.get (Requesturl);        if (method = = null) {return;        } Class Beanclass = Method.getdeclaringclass ();        Controller Controller = (Controller) beanclass.getannotation (Controller.class);        Object bean = Beaninstancemap.get (Controller.value ());            try {map<string, string[]> requestparametermap = Request.getparametermap ();            object[] args = new Object[requestparametermap.entryset (). Size ()];            int index = 0;                For (Map.entry Entry:requestParameterMap.entrySet ()) {Args[index] = Entry.getvalue ();            index++;        } method.invoke (bean, args); } catch (Illegalaccessexception |        InvocationTargetException e) {e.printstacktrace (); }    }}

Web. XML automatically generates corresponding code after the servlet is created

<load-on-startup> Add this tag, when Tomcat starts automatically loads the specified servlet greater than or equal to 0 o'clock start tomcat loads the servlet's init () method The smaller the number, the higher the priority of the load

<url-pattern>/This tag is the Tomcat request scan path, which will call the servlet corresponding Doget or Dopost method

<?xml version= "1.0" encoding= "UTF-8"? ><web-app xmlns= "Http://xmlns.jcp.org/xml/ns/javaee"         xmlns:xsi= "Http://www.w3.org/2001/XMLSchema-instance"         xsi:schemalocation= "HTTP://XMLNS.JCP.ORG/XML/NS/JAVAEE/HTTP// Xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd "         version=" 3.1 ">    <servlet>        <servlet-name >DispatcherServlet</servlet-name>        <servlet-class>com.hongsen.servlet.dispatcherservlet</ Servlet-class>        <load-on-startup>1</load-on-startup>

    </servlet>    <servlet-mapping>        <servlet-name>DispatcherServlet</servlet-name>        <url-pattern>/</url-pattern>    </servlet-mapping></web-app>

Creating a Controller class

Package Com.hongsen.controller, @Controller ("TestController") @RequestMapping ("/test") public class TestController {    @Resource ("Testaddservice")    private Testaddserviceimpl testaddservice;    @Resource ("Testdelservice")    private Testdelserviceimpl testdelservice;    @RequestMapping ("/add.json") public    void Testadd () {        testaddservice.add ();    }    @RequestMapping ("/del.json") public    void Testdel (Object Num1, Object num2) {        Testdelservice.del ( Num1.tostring (), num2.tostring ());}    }

Creating service Interfaces and implementing classes

Package Com.hongsen.service;public interface Testaddservice {    void Add (String num);}

Package Com.hongsen.service, @Service ("Testaddservice") public class Testaddserviceimpl implements testaddservice{    @Override public    void Add (String num) {        System.out.println ("The Add method executes! ");    }}

After the deployment of Tomcat starts successfully:

Visit: Http://localhost:8080/test/add.json

SPRINGMVC Framework Implementation