Java Reflection uses

 PackageCom.mycompany.helloworld.refect;ImportJava.lang.reflect.Field;ImportJava.lang.reflect.Method;/*** Method call using Reflection * Createy by user on 7/19/2018.17:57*/ Public classDemo { Public Static voidMain (string[] args)throwsException {Class clazz= User.class; Object obj=clazz.newinstance (); User u=NewUser ("Xiaoming"); //getdeclaredfields Get field         for(Field f:clazz.getdeclaredfields ()) {//The field is not allowed to be accessed through reflection when the result of Isaccessible () is falseF.setaccessible (true); System.out.println (F.getname ()+ ":" +f.get (u)); }        //set the dynamic call method to set the parameters of a dynamically called method to be of type stringMethod Urimethod = Clazz.getmethod ("Sayhel", String.class); //Dynamic Call MethodUrimethod.invoke (obj, "This is the print in app"); }     Public Static classUser {PrivateString name; PrivateInteger age;  PublicUser () {} PublicUser (String name) { This. Name =name; }         Public voidSayhel (String desc) {System.out.println ("Come--->" +desc); }         PublicString GetName () {returnname; }         Public voidsetName (String name) { This. Name =name; }         PublicInteger getage () {returnAge ; }         Public voidsetage (Integer age) { This. Age =Age ; }    }}------------------------------------------------------------ PackageCom.mycompany.helloworld.refect;ImportJava.lang.reflect.Field;ImportJava.lang.reflect.Method;ImportJava.util.HashMap;ImportJava.util.Map; Public classCommonservlet {Private Static Finalmap<string, string> header_field_relatetion =NewHashmap<string, string>(); Static{header_field_relatetion.put ("Content-type", "Setcontent_type"); Header_field_relatetion.put ("Accept-language", "Setaccept_language"); Header_field_relatetion.put ("Cookie", "Setcookie"); Header_field_relatetion.put ("Origin", "Setorigin"); Header_field_relatetion.put ("Locale", "SetLocale"); Header_field_relatetion.put ("Host", "Sethost"); Header_field_relatetion.put ("Authorization", "Setauthorization"); }    PrivateMetaObject MessageHeader =NewMetaObject ();  Public Static voidMain (string[] args)throwsException {System.out.println ("Refect------Start"); Fillimixobjectheader (NewCommonservlet ()); }    /*** HttpServletRequest converted to MetaObject using reflection *@paramRequestmessage*/    Private Static voidFillimixobjectheader (Commonservlet requestmessage)throwsException {Try {            /*** Get the MessageHeader field in the Commonrequest class*/Field Headerfield= Requestmessage.getclass (). Getdeclaredfield ("MessageHeader"); //The field is not allowed to be accessed through reflection when the result of Isaccessible () is falseHeaderfield.setaccessible (true); //Gets the reflection field that is used when object reflection calls the methodObject Header =Headerfield.get (requestmessage); //Gets the type of the reflection field used to get the dynamic call methodClass<?> headercls =Headerfield.gettype (); /*** Using reflection to dynamically invoke the method inside the class MessageHeader*/             for(Map.entry<string, string>Relatetion:HEADER_FIELD_RELATETION.entrySet ()) {String value=Relatetion.getkey (); if(Value! =NULL&&!value.trim (). Equals ("")) {                    //set the dynamic call method to set the parameters of a dynamically called method to be of type stringMethod Headitemmethod = Headercls.getmethod (Relatetion.getvalue (), String.class); Headitemmethod.invoke (header, value); //Dynamic Invocation                }            }            //dynamically call the Seturi method inside the MessageHeader class, set the arguments for the dynamically called method to be of type stringMethod Urimethod = Headercls.getmethod ("Seturi", String.class); Urimethod.invoke (header,"Http://localhost:8080/tbs"); //Dynamic invocation of the Setmethod method inside the MessageHeader classMethod Methodmethod = Headercls.getmethod ("Setmethod", String.class); Methodmethod.invoke (header,"GET");        Headerfield.set (Requestmessage, header); } Catch(Exception e) {e.printstacktrace (); }    }     Public Static classMetaObject {PrivateString Method; PrivateString authorization; PrivateString host; PrivateString locale; PrivateA String cookie; PrivateString Accept_language; PrivateString Content_Type; PrivateString Origin;  Public voidSeturi (String uri) {System.out.println ("Seturi:" +URI); }         Public voidSetmethod (String method) {System.out.println ("Setmethod:" +method); }         Public voidsetauthorization (String var1) {System.out.println ("Setauthorization:" +var1);  This. Authorization =var1; }         Public voidSethost (String host) {System.out.println ("Sethost:" +host);  This. Host =host; }         Public voidSetLocale (String locale) {System.out.println ("SetLocale:" +locale);  This. Locale =locale; }         Public voidSetcookie (String cookie) {System.out.println ("Setcookie:" +cookies);  This. cookie =cookies; }         Public voidsetaccept_language (String accept_language) {System.out.println ("Setaccept_language:" +accept_language);  This. Accept_language =Accept_language; }         Public voidSetcontent_type (String content_type) {System.out.println ("Setcontent_type:" +content_type);  This. Content_Type =Content_Type; }         Public voidSetorigin (String origin) {System.out.println ("Setorigin:" +origin);  This. Origin =origin; }    }}

Java reflection using