TreeMap排序和Map的遍歷

import java.util.Comparator;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import java.util.Map.Entry;

public class Test4 {
 public static void main(String[] args) {
  Map<String, String> treeMap = new TreeMap<String, String>(new Comparator<String>() {
   public int compare(String str1, String str2){
    return str1.compareTo(str2);
   }
  });
  treeMap.put("abc", "you");
  treeMap.put("bcd", "aou");
  
  Set<Entry<String, String>> set = treeMap.entrySet();
  for(Iterator<Entry<String, String>> it = set.iterator(); it.hasNext(); ){
   Entry<String, String> entry = it.next();
   String key = entry.getKey();
   String value = entry.getValue();
   System.out.println(key);
  }
  
 }
}