Java中int[]与Integer[]相互转化的方法，java基础知识面试重点总结

int[] result = new int[IntegerArray.length];
for (int i = 0; i < IntegerArray.length; i++) {
result[i] = IntegerArray[i].intValue();
}
return result;
}
Apache Commons Lang 工具类 ArrayUtils

org.apache.commons
commons-lang3
3.12.0
import org.apache.commons.lang3.ArrayUtils;
public class ArrayConvertExample {
public static void main(String[] args) {
int[] obj = new int[] { 1, 2, 3 };
Integer[] newObj = ArrayUtils.toObject(obj);
Integer[] obj2 = new Integer[] { 4, 5, 6 };
int[] newObj2 = ArrayUtils.toPrimitive(obj2);
Integer[] obj3 = new Integer[] { 7, 8, null };
int[] newObj3 = ArrayUtils.toPrimitive(obj2, 0);
}
}
ArrayUtils.toObject()与ArrayUtils.toPrimitive()源码如下：
package org.apache.commons.lang3;
public class ArrayUtils {
…
public static final Integer[] EMPTY_INTEGER_OBJECT_ARRAY = new Integer[0];
//Convert int[] to Integer[]
public static Integer[] toObject(final int[] array) {
if (array == null) {
return null;
} else if (array.length == 0) {
return EMPTY_INTEGER_OBJECT_ARRAY;
}
final Integer[] result = new Integer[array.length];
for (int i = 0; i < array.length; i++) {
result[i] = Integer.valueOf(array[i]);
}
return result;
}
public static final int[] EMPTY_INT_ARRAY = new int[0];
//Convert Integer[] to int[]
public static int[] toPrimitive(final Integer[] array) {
if (array == null) {
return null;
} else if (array.length == 0) {
return EMPTY_INT_ARRAY;
}
final int[] result = new int[array.length];