题目：写一个Array的工具类，含有toString、Max、Min、Average、Merg、isExist、equals、find等操作。
答：
package util;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* @author daniel
* Array util
*/
public class ArrayUtil {
/**
* ToString
* @param array
* @return
*/
public static String getToString(Object[] array){
StringBuffer sb=new StringBuffer("{");
for(int i=0;i
sb.append(array[i].toString());
if(i!=array.length-1){
sb.append(",");
}
}
sb.append("}");
return sb.toString();
}
/**
* Get the max item's key
* @param array
* @return
*/
public static int maxKey(int[] array){
int maxId=-1;
for (int i = 0; i < array.length; i++) {
if (maxId==-1 || array[i]>array[maxId]) {
maxId=i;
}
}
return maxId;
}
/**
* Get the min item's key
* @param array
* @return
*/
public static int minKey(int[] array){
int minId=-1;
for (int i = 0; i < array.length; i++) {
if (minId==-1 || array[i]
minId=i;
}
}
return minId;
}
/**
* Get the average of the int array
* @param array
* @return
*/
public static int average(int[] array){
int sum=0;
if (array.length==0) {
throw new IllegalArgumentException("Array length is zero!");
}
for (int i = 0; i < array.length; i++) {
sum+=array[i];
}
return sum/array.length;
}
/**
* merg two array to one
* @param one
* @param other
* @return
*/
public static Object[] merg(Object[] one,Object[] other){
Object[][] tmp=new Object[][]{one,other};
Object[] result=null;
List res=null;
int size = 0;
for (int i = 0; i < tmp.length; i++) {
size+=tmp[i].length;
}
res=new ArrayList(size);
for (int i = 0; i < tmp.length; i++) {
for (int j = 0; j < tmp[i].length; j++) {
res.add(tmp[i][j]);
}
}
return res.toArray();
}
/**
* Check value exists
* @param array
* @param item
* @return
*/
public static boolean exists (Object[] array, Object item) {
if (item==null) {
return false;
}
List list=Arrays.asList(array);
return list.contains(item);
}
/**
* Test
* @param args
*/
public static void main(String[] args) {
Object[] obj=new Object[]{0,1,"zhou",2,3,4,5,6,"daniel"};
//toString
System.out.println(getToString(obj));
//get max
int[] values=new int[]{0,1,2,3,4,5,6,8,33,2};
System.out.println(values[maxKey(values)]);
//get min
System.out.println(values[minKey(values)]);
//get average
System.out.println(average(values));
//merg two array to one
Object[] object=new Object[]{203,15,26,"jack"};
Object[] all= merg(obj,object);
System.out.println(getToString(all));
//check value exist in array
System.out.println(exists(obj,"daniel"));
}
}
责任编辑：小草
