Java Reflection Basics

The reflection mechanism is in the running state, for any class, can know all the properties and methods of this class, for any one object, can call any of its methods and properties; This dynamically acquired information and the ability to dynamically invoke the method of the object is called the reflection mechanism of the Java language. Link

The main method of reflection

Method/Property	Explain
Getdeclaredmethods ()	Get all the methods
Getreturntype ()	Get the return type of the method
Getparametertypes ()	Get the incoming parameter type for a method
Getdeclaredmethod (" method name", Parameter type. Class,......)	Get a specific approach
Getdeclaredconstructors ()	Get all the construction methods
getdeclaredconstructor ( parameter type. Class,......)	Get a specific construction method
Getsuperclass ()	Gets the parent class of a class
Getinterfaces ()	An interface that takes a class implementation
Getdeclaredfield ()	Gets the specified property of the declaration
Getdeclaredfields ()	Get all properties of a claim
GetField ()	Gets the specified property
GetFields ()	Get all Properties
Field.get (Clazz)	Get class Properties
Field.set (Clazz,property);	Set class properties

Reflection-related class Java.lang.Class;                Java.lang.reflect.Constructor; Java.lang.reflect.Field;        Java.lang.reflect.method;java.lang.reflect.modifier;

reflection accesses the class's Properties class<?> Clazz =NULL; Try{clazz= Class.forName ("Com.simple.dec.advance.basic.basic1.SonClazz"); Field field= Clazz.getdeclaredfield ("Sonpwd"); Field.setaccessible (true); Object result= Field.get ( This);            Zlog.zze (result); Field.set ( This, "Java Reflection mechanism"); Result= Field.get ( This);        Zlog.zze (result); } Catch(Exception e) {e.printstacktrace (); }

method class for reflection Access class<?> Clazz =NULL; Try{clazz= Class.forName ("Com.simple.dec.advance.basic.basic1.SonClazz"); Method Method= Clazz.getmethod ("Getsonpwd");//Method.invoke (Clazz.newinstance ());Object result = Method.invoke ( This);   Zlog.zze (result); //with no parametersmethod = Clazz.getmethod ("Getsonemail"); Result= Method.invoke ( This);   Zlog.zze (result); //with parameters, access to private methodsmethod = Clazz.getdeclaredmethod ("Getsum",int.class, String.class); Method.setaccessible (true); Result= Method.invoke ( This, "Isson ...");            Zlog.zze (result); Method= Clazz.getmethod ("Getsum",int.class, String.class); Result= Method.invoke ( This, "Isson ...");        Zlog.zze (result); } Catch(Exception e) {e.printstacktrace (); }

Reference:

A detailed explanation of the Java reflection mechanism

Java Reflection

Java Reflection and annotations

The reflection mechanism in Java

Alternate code

    /*** A method that calls a subclass * Cannot access private methods*/    Private voidGetsonmethod () {Class<?> Clazz =NULL; Try{clazz= Class.forName ("Com.simple.dec.advance.basic.basic1.SonClazz"); Method Method= Clazz.getmethod ("Getsonpwd");//Method.invoke (Clazz.newinstance ());Object result = Method.invoke ( This);   Zlog.zze (result); //with no parametersmethod = Clazz.getmethod ("Getsonemail"); Result= Method.invoke ( This);   Zlog.zze (result); //with parameters, access to private methodsmethod = Clazz.getdeclaredmethod ("Getsum",int.class, String.class); Method.setaccessible (true); Result= Method.invoke ( This, "Isson ...");            Zlog.zze (result); Method= Clazz.getmethod ("Getsum",int.class, String.class); Result= Method.invoke ( This, "Isson ...");        Zlog.zze (result); } Catch(Exception e) {e.printstacktrace (); }    }    /*** Get all methods of subclasses*/    Private voidGetsonmethodall () {Class<?> Clazz =NULL; Try{clazz= Class.forName ("Com.simple.dec.advance.basic.basic1.SonClazz"); Method method[]=Clazz.getmethods ();  for(inti = 0; i < method.length; ++i) {Class<?> ReturnType =Method[i].getreturntype (); Class<?> para[] =method[i].getparametertypes (); inttemp =method[i].getmodifiers (); System.out.print (modifier.tostring (temp)+ " "); System.out.print (Returntype.getname ()+ "  "); System.out.print (Method[i].getname ()+ " "); System.out.print ("(");  for(intj = 0; J < Para.length; ++j) {System.out.print (Para[j].getname ()+ "+" + "arg" +j); if(J < Para.length-1) {System.out.print (","); }} Class<?> exce[] =method[i].getexceptiontypes (); if(Exce.length > 0) {System.out.print (") throws");  for(intk = 0; K < Exce.length; ++k) {System.out.print (Exce[k].getname ()+ " "); if(K < Exce.length-1) {System.out.print (","); }                    }                } Else{System.out.print (")");            } System.out.println (); }        } Catch(ClassNotFoundException e) {e.printstacktrace (); } zlog.zze (""); }    /*** Call a property of subclass * Direct access to private property*/    Private voidGetsonproperty () {Class<?> Clazz =NULL; Try{clazz= Class.forName ("Com.simple.dec.advance.basic.basic1.SonClazz"); Field field= Clazz.getdeclaredfield ("Sonpwd"); Field.setaccessible (true); Object result= Field.get ( This);            Zlog.zze (result); Field.set ( This, "Java Reflection mechanism"); Result= Field.get ( This);        Zlog.zze (result); } Catch(Exception e) {e.printstacktrace (); }    }    /*** Get all attributes of subclass*/    Private voidGetsonpropertyall () {Class<?> Clazz =NULL; Try{clazz= Class.forName ("Com.simple.dec.advance.basic.basic1.SonClazz"); System.out.println ("=============== This class property ==============="); //get all the properties of this classfield[] field =Clazz.getdeclaredfields ();  for(inti = 0; i < field.length; i++) {                //Permission Modifiers                intMo =field[i].getmodifiers (); String Priv=modifier.tostring (MO); //Property Typeclass<?> type =Field[i].gettype (); System.out.println (Priv+ "" + type.getname () + "" + field[i].getname () + ";"); } System.out.println ("========== implemented interface or parent class Property =========="); //gets the implemented interface or properties of the parent classfield[] Filed1 =Clazz.getfields ();  for(intj = 0; J < Filed1.length; J + +) {                //Permission Modifiers                intMo =filed1[j].getmodifiers (); String Priv=modifier.tostring (MO); //Property Typeclass<?> type =Filed1[j].gettype (); System.out.println (Priv+ "" + type.getname () + "" + filed1[j].getname () + ";"); }        } Catch(ClassNotFoundException e) {e.printstacktrace (); }    }

Java Reflection Basics