toarray.java

电子工业出版社出版的《java2应用开发指南》配套光盘源代码

import java.util.*;
class ToArray 
{
    public static void main(String[] args) 
{
        Vector v = new Vector(Arrays.asList(new String[]{"dog", null}));
        Object[] objs = v.toArray();
        print(objs);
        // If we passed in a string array, we can cast
        // the result to a string array.
        String[] strings = (String[])v.toArray(new String[0]);
        print(strings);
        // Try adding something other than a string to the vector.
        v.add(new Integer(0));
        print( v.toArray() ); 
        // The Integer object can not be stored in the string array.
        //print( v.toArray(new String[0]) ); 
    }
    static void print(Object[] arr) 
{
        System.out.println(Arrays.asList(arr));
    }
}