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package com.accp.array;

import java.lang.reflect.Array;

public class GrowArrayTest {
public static void main(String[] args) {
Integer[] array = {1,2,3,4}; //ͨÓÃÀ©Õ¹
arrayPrint(array);
array = (Integer[])goodArrayGrow(array);
arrayPrint(array);


String[] str = {"xw","xz"};
arrayPrint(str);
str = (String[])badArrayGrow(str); //»á±¨ClassCastExceptionÒì³£,ÎÞ·¨½«Objectת»»³ÉStringÀàÐÍ
arrayPrint(str);

int[] a = null;
goodArrayGrow(a);
arrayPrint(a);

}

public static Object goodArrayGrow(Object o) {
Class clazz = o.getClass(); //µÃµ½ÀàÐÍÐÅÏ¢
if (!clazz.isArray())
return null;

Class type = clazz.getComponentType(); //µÃµ½oµÄÀàÐÍ
int newLength = Array.getLength(o) * 11 / 10 + 10;

Object newArray = Array.newInstance(type, newLength); //´´½¨Ò»¸öеÄArray, type = clazz.getComponentype()
System.arraycopy(o, 0, newArray, 0, Array.getLength(o));
return newArray;
}

public static Object[] badArrayGrow(Object[] o){
int newLength = o.length * 11 /10 +10;
Object[] newArray = new Object[o.length];
System.arraycopy(o, 0, newArray, 0, o.length);
return newArray;
}

public static void arrayPrint(Object a) { // ±éÀúÊä³öÊý×éÖµ


Class clazz = a.getClass(); // µÃµ½ÀàÐÍÐÅÏ¢
if (!clazz.isArray())
return;

Class type = clazz.getComponentType(); // µÃµ½ÀàÐÍ
Integer length = Array.getLength(a); // µÃµ½³¤¶È

System.out.print(type.getName() + "[" + length + "]={"); // ¸ñʽ»¯Êä³ö

for (int i = 0; i < Array.getLength(a); i++)
System.out.print(Array.get(a, i) + " ");
System.out.println("}");

}
}