Java reflection, know the class name to create a class, you can also set the value of the private property, java private

Java reflection, know the class name to create a class, you can also set the value of the private property, java private

I just learned reflection, and I feel that reflection is powerful. So I want to write a blog to record my learning achievements.

Use reflection to create objects.

Class c1 = Class. forName ("test. Person"); // create a Class by Class name. Here test. person is just a Class name ,. The person class code is at the bottom of // This article/*** Case 1: Call the construction method without parameters to create an object */Person p = c1.newInstance (); // In this case, the/*** scenario 2 is created: Call the construction method with parameters */Constructor cs = c1.getConstructor (String. class, int. class); // The parameter type of the constructor is written in the brackets, that is, it is added later. class is ready for Person p = (Person) cs. newInstance ("Zhang San", 22); // call the constructor to generate an objectView Code

Use reflection to set Private attributes

Try {Class clazz = Class. forName ("testPerson"); Person p = (Person) clazz. newInstance (); Field f1 = clazz. getDeclaredField ("name"); f1.setAccessible (true); // sets whether private attributes f1.set (p, "wfadf") can be operated; System. out. println (f1.get (p);} catch (Exception e) {// TODO Auto-generated catch block throw new RuntimeException (e );}

Person code

package test;public class Person {    private String name;    private int age;        public Person() {            }    public Person(String name, int age) {            this.name = name;        this.age = age;    }    public String getName() {        return name;    }/*    public void setName(String name) {        this.name = name;    }*/    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }}