下面小编就为大家带来一篇浅谈java中的TreeMap 排序与TreeSet 排序。小编觉得挺不错的,现在就分享给大家,也给大家做个参考。一起跟随小编过来看看吧
TreeMap:
package com; import java.util.Comparator; import java.util.TreeMap; public class Test5 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub TreeMap tree = new TreeMap( new Comparator() { @Override public int compare(Object o1, Object o2) { // TODO Auto-generated method stub if(o1 == null || o2 == null){ return 0; } return o1.toString().compareTo(o2.toString()); } } ); tree.put("k", "1"); tree.put("ba", "2"); tree.put("z", "3"); tree.put("d", "4"); tree.put("e", "5"); tree.put("an", "6"); tree.put("c", "7"); for(String str : tree.keySet()){ System.out.println(str); } } }
经测试默认是按照 KEY 进行排序的。
但是可以写对象比较器,进行自定义排序。
TreeSet : 自定义倒序排序,默认按照正序排序,1,2,3,4,5,6
package com; import java.util.Comparator; import java.util.TreeSet; public class Test6 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub TreeSet tree = new TreeSet(new Comp<div style="color:transparent">来源gaodai^.ma#com搞#代!码网</div>arator() { @Override public int compare(Object o1, Object o2) { // TODO Auto-generated method stub if(o1 == null || o2 == null){ return 0; } if(Integer.parseInt(o1.toString()) > Integer.parseInt(o2.toString())){ return -1; }else if(Integer.parseInt(o1.toString()) <Integer.parseInt(o2.toString())){ return 1; }else{ return 0; } } }); tree.add(4); tree.add(5); tree.add(6); tree.add(1); tree.add(2); tree.add(3); for(Object o : tree){ System.out.println(o); } } }
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