Java traversal map, List, Array

1. Iterate through the array, using a For loop or foreach (I recommend it)

int arr[] = {2, 3, 1};  System.out.println ("----1----one-dimensional array before sorting");    for (int  x:arr) {  // Output The value  of the array element individually }

2. Traversing HashMap, it is recommended to use an iterator or a foreach

 Public DoubleGetpaymoney () {//using the foreach traversal         for(Goodorder goodorder:goodorderslist) {ListGoodorder.getgood (); //using for Traversal             for(inti = 0; I < goods.size (); i++) {map map=Goods.get (i); Iterator ITER=Map.entryset (). iterator (); //using iterators to traverse                 while(Iter.hasnext ()) {Map.entry Entry=(Map.entry) iter.next (); intCount =(Integer) Entry.getkey (); Good GD=(good) entry.getvalue (); Paymoney= (double.valueof (Paymoney) + double.valueof (Gd.getgood_price ()) *count); }            }        }        returnPaymoney; }

3. Traverse ArrayList

It is recommended to use a For loop to resolve (internal not locked, the most efficient, but when writing multi-threading to consider the problem of concurrent operations; the other two are when the state of the lock is accessed)

Java traversal map, List, Array