Here is a simple example to convert primitive int array to Integer array and vice versa
Using regular for-loop
package com.programtalk.learn.java.beginner;
//author programtalk.com
public class PrimitiveObjectArrayConversion {
public static void main(String[] args) {
System.out.println("######### Convert Primitive int[] to Integer[] ##########");
int[] prmitiveArray = new int[] { 10, 11, 12 };
Integer[] objectArray = convert2ObjectArray(prmitiveArray);
System.out.println("Print converted Array");
for (Integer eachInteger : objectArray) {
System.out.println(eachInteger.getClass() +" :" +eachInteger);
}
System.out.println("\n######### Convert Object Integer[] to Primitive int[] ##########");
System.out.println("Print converted Array");
Integer[] obj2 = new Integer[] { 20, 21, 22 };
int[] newObj2 = convert2PrimitiveArray(obj2);
for (int eachPrimitiveInt : newObj2) {
System.out.println("primitive int : " + eachPrimitiveInt);
}
}
public static Integer[] convert2ObjectArray(int[] intArray) {
Integer[] result = new Integer[intArray.length];
for (int i = 0; i < intArray.length; i++) {
result[i] = Integer.valueOf(intArray[i]);
}
return result;
}
public static int[] convert2PrimitiveArray(Integer[] integerArray) {
int[] result = new int[integerArray.length];
for (int i = 0; i < integerArray.length; i++) {
result[i] = integerArray[i].intValue();
}
return result;
}
}
And the output is :
######### Convert Primitive int[] to Integer[] ########## Print converted Array class java.lang.Integer :10 class java.lang.Integer :11 class java.lang.Integer :12 ######### Convert Object Integer[] to Primitive int[] ########## Print converted Array primitive int : 20 primitive int : 21 primitive int : 22
Java 8
Using Stream APIs of Java 8.
package com.programtalk.learn.java.beginner;
import java.util.Arrays;
//author programtalk.com
public class PrimitiveObjectArrayConversionJava8 {
public static void main(String[] args) {
System.out.println("######### Convert Primitive int[] to Integer[] ##########");
int[] prmitiveArray = new int[] { 10, 11, 12 };
Integer[] objectArray = convert2ObjectArray(prmitiveArray);
System.out.println("Print converted Array");
for (Integer eachInteger : objectArray) {
System.out.println(eachInteger.getClass() +" :" +eachInteger);
}
System.out.println("\n######### Convert Object Integer[] to Primitive int[] ##########");
System.out.println("Print converted Array");
Integer[] obj2 = new Integer[] { 20, 21, 22 };
int[] newObj2 = convert2PrimitiveArray(obj2);
for (int eachPrimitiveInt : newObj2) {
System.out.println("primitive int : " + eachPrimitiveInt);
}
}
public static Integer[] convert2ObjectArray(int[] intArray) {
return Arrays.stream(intArray).boxed().toArray( Integer[]::new );
}
public static int[] convert2PrimitiveArray(Integer[] integerArray) {
return Arrays.stream(integerArray).mapToInt(Integer::intValue).toArray();
}
}
Commons Arrayutils
If you are not using java 8 and still want to have a oneliner. Use ArrayUtils from commons-lang3.
package com.programtalk.learn.java.beginner;
import org.apache.commons.lang3.ArrayUtils;
//author programtalk.com
public class PrimitiveObjectArrayConversionArrayUtils {
public static void main(String[] args) {
System.out.println("######### Convert Primitive int[] to Integer[] ##########");
int[] prmitiveArray = new int[] { 10, 11, 12 };
Integer[] objectArray = convert2ObjectArray(prmitiveArray);
System.out.println("Print converted Array");
for (Integer eachInteger : objectArray) {
System.out.println(eachInteger.getClass() +" :" +eachInteger);
}
System.out.println("\n######### Convert Object Integer[] to Primitive int[] ##########");
System.out.println("Print converted Array");
Integer[] obj2 = new Integer[] { 20, 21, 22 };
int[] newObj2 = convert2PrimitiveArray(obj2);
for (int eachPrimitiveInt : newObj2) {
System.out.println("primitive int : " + eachPrimitiveInt);
}
}
public static Integer[] convert2ObjectArray(int[] intArray) {
return ArrayUtils.toObject(intArray);
}
public static int[] convert2PrimitiveArray(Integer[] integerArray) {
return ArrayUtils.toPrimitive(integerArray);
}
}