java修改数组长度(原稿)

java中没有关于修改数组长度的api,在此本人提供了修改数组长度的两个函数:arrayAddLength()和arrayReduceLength().详细见代码.

import java.lang.reflect.Array;

/**
* Description: This class is used to adjust array length.
* @author sailing
*
*/
public class ArrayTest {

/**
* @param args
*/
public static void main(String[] args) {
int a[]= new int[]{0,1,2,3,4,5};
int b[]= new int[]{0,1,2,3,4,5};
a = (int[]) arrayAddLength(a,2);
b = (int[]) arrayReduceLength(b,2);
//out print array lenght
System.out.println(a.length);
for (int i=0;i<a.length;i++){
System.out.print(a[i]);
}
System.out.println();

System.out.println(b.length);
for (int i=0;i<b.length;i++){
System.out.print(b[i]);
}
}
/**
* Description: Array add length
* @param oldArray
* @param addLength
* @return Object
*/
public static Object arrayAddLength(Object oldArray,int addLength) {
Class c = oldArray.getClass();
if(!c.isArray())return null;
Class componentType = c.getComponentType();
int length = Array.getLength(oldArray);
int newLength = length + addLength;
Object newArray = Array.newInstance(componentType,newLength);
System.arraycopy(oldArray,0,newArray,0,length);
return newArray;
}
/**
* Description: Array reduce lenght
* @param oldArray
* @param reduceLength
* @return Object
*/
public static Object arrayReduceLength(Object oldArray,int reduceLength) {
Class c = oldArray.getClass();
if(!c.isArray())return null;
Class componentType = c.getComponentType();
int length = Array.getLength(oldArray);
int newLength = length - reduceLength;
Object newArray = Array.newInstance(componentType,newLength);
System.arraycopy(oldArray,0,newArray,0,newLength);
return newArray;
}
}