JAVA功能代码《13》----在Java中调整数组大小

public class resizeArray {
/**
* Reallocates an array with a new size, and copies the contents of the old
* array to the new array.
*
* @param oldArray
*            the old array, to be reallocated.
* @param newSize
*            the new array size.
* @return A new array with the same contents.
*/
private static Object resizeArray(Object oldArray, int newSize) {
int oldSize = java.lang.reflect.Array.getLength(oldArray);
Class elementType = oldArray.getClass().getComponentType();
Object newArray = java.lang.reflect.Array.newInstance(elementType,
newSize);
int preserveLength = Math.min(oldSize, newSize);
if (preserveLength > 0)
System.arraycopy(oldArray, 0, newArray, 0, preserveLength);
return newArray;
}

// Test routine for resizeArray().
public static void main(String[] args) {
int[] a = { 1, 2, 3 };
a = (int[]) resizeArray(a, 5);
a[3] = 4;
a[4] = 5;
for (int i = 0; i < a.length; i++)
System.out.println(a[i]);
}
}