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]); } }
