Java basic Knowledge Hardening collection Frame note 52:map collection of the traversal key for the set of map values

1. Traversal of the Map collection

Map--Couples on
Ideas:
A: Bring all the husbands together.
B: Walk through the collection of husbands, get every husband.
C: Ask the husband to find his wife.

Transformation:
A: Get all the keys
B: The collection of traversal keys, get each key
C: According to the key to find the value

2. code example:

1  Packagecn.itcast_01;2 3 ImportJava.util.HashMap;4 ImportJava.util.Map;5 ImportJava.util.Set;6 7  Public classMapDemo3 {8      Public Static voidMain (string[] args) {9         //To create a collection objectTenmap<string, string> map =NewHashmap<string, string>(); One  A         //Create an element and add it to the collection -Map.put ("Yang", "Little Dragon Girl")); -Map.put ("Guo Jing", "Huang Rong"); theMap.put ("Yang Kang", "Munians"); -Map.put ("Chen Xuanfeng", "MUI Wind"); -  -         //Traverse +         //get all the keys -Set<string> set =Map.keyset (); +         //iterate through the collection of keys to get each key A          for(String key:set) { at             //find values by key -String value =Map.get (key); -SYSTEM.OUT.PRINTLN (key + "---" +value); -         } -     } -}

Run the results as follows:

Java basic Knowledge Hardening collection Frame note 52:map collection of the traversal key for the set of map values