Map实例

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import java.util.*;

public class TestMap01 {
public static void main(String[] args) {
    // Create a HashMap
    Map<String, Integer> hashMap = new HashMap<String, Integer>();
    hashMap.put("Smith", 30);
    hashMap.put("Anderson", 31);
    hashMap.put("Lewis", 29);
    hashMap.put("Cook", 29);

System.out.println("Display entries in HashMap");
System.out.println(hashMap);

    // Create a TreeMap from the previous HashMap
    Map<String, Integer> treeMap =
      new TreeMap<String, Integer>(hashMap);
    System.out.println("\nDisplay entries in ascending order of key");
    System.out.println(treeMap);

//    TreeSet<String> name=treeMap.keySet();
  TreeSet<String> name=new TreeSet<String>(treeMap.keySet());
    System.out.println(name);

    TreeSet<Integer> age=new TreeSet<Integer>(treeMap.values());
    System.out.println(age);


    Set<Map.Entry<String, Integer>> entrySet = treeMap.entrySet();

    // Get key and value from each entry
    for (Map.Entry<String, Integer> entry: entrySet)
      System.out.println( entry.getKey()+ "\t" + entry.getValue());
}
}