我要评论动态改变数组的长度
/** * reallocates an array with a new size, and copies the contents
* * of the old array to the new array.
* * @param oldarray the old array, to be reallocated.
* * @param newsize the new array size.
* * @return a new array with the same contents.
* */
private static object resizearray (object oldarray, int newsize) {
int oldsize = java.lang.reflect.array.getlength(oldarray);
class elementtype = oldarray.getclass().getcomponenttype();
object newarray = java.lang.reflect.array.newinstance(
elementtype,newsize);
int preservelength = math.min(oldsize,newsize);
if (preservelength > 0)
system.arraycopy (oldarray,0,newarray,0,preservelength);
return newarray; }
// test routine for resizearray().
public static void main (string[] args) {
int[] a = {1,2,3};
a = (int[])resizearray(a,5);
a[3] = 4;
a[4] = 5;
for (int i=0; i<a.length; i++)
system.out.println (a[i]);
}
代码只是实现基础方法，详细处理还需要你去coding哦>>
把 array 转换成 map
import java.util.map;
import org.apache.commons.lang.arrayutils;
public class main {
public static void main(string[] args) {
string[][] countries = { { "united states", "new york" },
{ "united kingdom", "london" },
{ "netherland", "amsterdam" },
{ "japan", "tokyo" },
{ "france", "paris" } };
map countrycapitals = arrayutils.tomap(countries);
system.out.println("capital of japan is " + countrycapitals.get("japan"));
system.out.println("capital of france is " + countrycapitals.get("france"));
}
}
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