Invoke Constructor
Apache Commons Lang 3.0 is a java library with lot of utilities and reusable components.
This requires the library commons-lang3-3.0.1.jar to be in classpath.
The following example shows using ConstructorUtils.invokeConstructor() API.
It returns a new instance by invoking the matching constructor.
package com.bethecoder.tutorials.commons_lang.common; public class Student extends Person { private static String DEFAULT_NAME = "Unknown" ; private String name; private int age; private String hobby; public Student () { } public Student ( String name, int age, String hobby ) { super () ; this .name = name; this .age = age; this .hobby = hobby; } 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; } public String getHobby () { return hobby; } public void setHobby ( String hobby ) { this .hobby = hobby; } public String toString () { return "Student[name = " + name + ", age = " + age + ", hobby = " + hobby + "]" ; } }
package com.bethecoder.tutorials.commons_lang.tests.reflections; import java.lang.reflect.InvocationTargetException; import org.apache.commons.lang3.reflect.ConstructorUtils; import com.bethecoder.tutorials.commons_lang.common.Student; public class InvokeConstructorTest { /** * @param args * @throws InstantiationException * @throws InvocationTargetException * @throws IllegalAccessException * @throws NoSuchMethodException */ public static void main ( String [] args ) throws NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException { Student stud = ConstructorUtils.invokeConstructor ( Student.class, "Sriram" , 2 , "Chess" ) ; System.out.println ( stud ) ; Integer intObj = ConstructorUtils.invokeConstructor ( Integer.class, "123456" ) ; System.out.println ( intObj ) ; } }
Student[name = Sriram, age = 2, hobby = Chess]
123456
