Java Api--treemap Class

1, TreeMap class overviewKey is a red-black tree structure, which guarantees the ordering and uniqueness of keys 2. TreeMap CaseTreemap<string,string> treemap<student,string> Example 1:

 PackageTreemapdemos;ImportJava.util.Set;ImportJava.util.TreeMap;/*** Created by Gao on 15-12-22.*//** TreeMap: is based on the red-black tree map interface implementation. * hashmap<string,string> * Key: String * Value: String*/ Public classTreeMapDemo01 { Public Static voidMain (string[] args) {//To create a collection objecttreemap<string, String> TM =NewTreemap<string, string>(); //creating elements and adding elementsTm.put ("Hello", "Hello"); Tm.put ("World", "worlds"); Tm.put ("Java", "Javanese"); Tm.put ("World", "2"); Tm.put ("Java ee", "java ee"); //iterating through the collectionSet<string> set =Tm.keyset ();  for(String key:set) {String value=Tm.get (key); SYSTEM.OUT.PRINTLN (Key+ "---" +value); }    }}

Output result: (unique and natural sort)

Hello---hello java---javanese java ee---java eeworld---World 2 Example 2:

 PackageTreemapdemos;ImportJava.util.Comparator;ImportJava.util.Set;ImportJava.util.TreeMap;/*** Created by Gao on 15-12-22.*//** treemap<student,string> * Key: Student * Value: String*/ Public classTreeMapDemo02 { Public Static voidMain (string[] args) {//To create a collection objectTreemap<student, String> TM =NewTreemap<student, String> (NewComparator<student>() {@Override Public intCompare (Student s1, Student S2) {intnum = S1.getage ()-S2.getage (); intnum2 = num = = 0?s1.getname (). CompareTo (S2.getname ()): num; returnnum2;        }        }); //Create student ObjectsStudent S1 =NewStudent ("Koh Phangan", 30); Student S2=NewStudent ("Willow Xia Hui", 35); Student S3=NewStudent ("Tong Pak Fu", 33); Student S4=NewStudent ("燕青", 32); Student S5=NewStudent ("Tong Pak Fu", 33); //Storage ElementsTm.put (S1, "Song Dynasty"); Tm.put (S2,Yuan Dynasty); Tm.put (S3,Ming Dynasty); Tm.put (S4,Qing Dynasty); Tm.put (S5,Han Dynasty); //TraverseSet<student> set =Tm.keyset ();  for(Student key:set) {String value=Tm.get (key); System.out.println (Key.getname ()+ "---" + key.getage () + "---" +value); }    }}

output Result: (unique and sort)Koh Phangan------Song Dynasty 燕青------qing fu pak Tong------Han Dynasty Hui---Yuan Dynasty

Java Api--treemap Class