Introduction to the mutual transfer between array list map in java

package util; 

import java.util.ArrayList; 
import java.util.Arrays; 
import java.util.HashMap; 
import java.util.List; 
import java.util.Map; 

import org.apache.commons.collections.MapUtils; 

public class Convert { 
public static void main(String[] args) { 
//1.数组转换为list，map 
String[] arr = {"123","456","789","123"}; 
List<String> list = Arrays.asList(arr); 
//数组转换为map,一维数组时，奇数为key,偶数为value,奇数个元素，最后一个舍掉 
//.二维数组当做两个一维数组 
Map map = MapUtils.putAll(new HashMap(), arr); 

String[][] ss = {{"a","b","e"},{"c","d","f"}}; 
MapUtils.debugPrint(System.out,arr,map); 
MapUtils.putAll(map, arr); 
MapUtils.debugPrint(System.out,arr,map); 
MapUtils.putAll(map, ss); 
MapUtils.verbosePrint(System.out,arr,MapUtils.invertMap(map)); 

//list 转换为arr 
List<String> ls = new ArrayList<String>(); 
ls.add("wch"); 
ls.add("name"); 
String[] as = (String[]) ls.toArray(); 

} 
}