建构方法( Constructor) public class safeArray i private int[] arri public SafeArray() f this(10);//预设10个元素 public SafeArray (int length) i arr new int [length]i建构方法（Constructor） public class SafeArray { private int[] arr; public SafeArray() { this(10); //预设10个元素 } public SafeArray(int length) { arr = new int[length]; } … }