java改变数组长度_Java修改数组长度

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.

[java] view plaincopyprint?

import java.lang.reflect.Array;

/**

* Description: This class is used to adjust array length.

* @author e421083458

*

*/

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

System.out.print(a[i]);

}

System.out.println();

System.out.println(b.length);

for (int i=0;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;

}

}