Java Basic Knowledge Enhancement Collection Framework note 59:map collection of TreeMap (treemap<string,string>) case

1. Overview of the TreeMap class:

The key is a red-black tree structure that guarantees the ordering and uniqueness of the keys .

2. TreeMap Case:

Treemap<string, string>

code example:

1  Packagecn.itcast_04;2 3 ImportJava.util.Set;4 ImportJava.util.TreeMap;5 6 /*7 * TreeMap: is based on the red-black tree map interface implementation. 8  * 9 * hashmap<string,string>Ten * Key: String One * Value: String A  */ -  Public classTreemapdemo { -      Public Static voidMain (string[] args) { the         //To create a collection object -treemap<string, String> TM =NewTreemap<string, string>(); -  -         //creating elements and adding elements +Tm.put ("Hello", "Hello"); -Tm.put ("World", "worlds"); +Tm.put ("Java", "Javanese"); ATm.put ("World", "2"); atTm.put ("Java ee", "java ee"); -  -         //iterating through the collection -Set<string> set =Tm.keyset (); -          for(String key:set) { -String value =Tm.get (key); inSYSTEM.OUT.PRINTLN (key + "---" +value); -         } to     } +}

Run the effect as follows:

Java Basic Knowledge Enhancement Collection Framework note 59:map collection of TreeMap (treemap<string,string>) case