Reflection in Java, knowing the class name creates a class, and you can set the value of a private property

Just learned the reflection, feel the function of reflection is very strong, so want to write a blog record of their own learning results.

Use reflection to create objects.

Class c1=class.forname ("Test. Person ");//create a class from the class name, where Test.person is just a class name. This person class code is//At the bottom of this article/*** Scenario 1: Call the parameterless constructor to create the object*/Person P=c1.newinstance ();//this creates it./*** Scenario 2: Calling a method with a parameter constructor*/Constructor CS=c1.getconstructor (String.class,int.class);//what is written in parentheses is the class of the parameter types of the constructor method, which is the addition of the following. class.Person p= (person) cs.newinstance ("Zhang San", 22);//invoking a constructor method to build an object

View Code

Use reflection to set private properties

    Try {    Class clazz=class.forname ("Testperson");    Person P=(person) clazz.newinstance ();    Field F1=clazz.getdeclaredfield ("name");    F1.setaccessible (true); // set whether private properties    can be manipulated F1.set (P, "WFADF"); System.out.println (F1.get (P));     Catch (Exception e) {        //  TODO auto-generated catch block        throw  New  runtimeexception (e);    }

Person Class Code

 Packagetest; Public classPerson {PrivateString name; Private intAge ;  PublicPerson () {} PublicPerson (String name,intAge ) {             This. Name =name;  This. Age =Age ; }     PublicString GetName () {returnname; }/*Public void SetName (String name) {this.name = name; }*/     Public intGetage () {returnAge ; }     Public voidSetage (intAge ) {         This. Age =Age ; }}

Reflection in Java, knowing the class name creates a class, and you can set the value of a private property