Java常用集合排序

快来打我* 2022-06-10 02:42 279阅读 0赞

## 1、list排序 ##

List<String> list = new ArrayList<String>(Arrays.asList("Clinton","Bush", "Trump", "Plata"));
    //可以控制是升序还是降序
    Collections.sort(list, new Comparator<String>()   {
         public int compare(String o1, String o2) {
               return o1.toString().compareTo(o2.toString());
         }
    });
    //Collections.sort(list);

**结果**：\[Bush, Clinton, Plata, Trump\]

## 2、数组排序 ##

String[] arr = new String[]{"Clinton", "Bush", "Trump", "Plata"};
    Arrays.sort(arr, new Comparator<String>() {
         public int compare(String o1, String o2) {
              return o1.toString().compareTo(o2.toString());
         }
    });
    //Arrays.sort(arr);

## 3、用TreeSet对set排序 ##

Set<String> set = new HashSet<String>(){
       {add("Clinton"); add("Bush"); add("Trump"); add("Plata");}};
    Set<String> sortedSet = new TreeSet<String>(new Comparator<String>() {
    	public int compare(String o1, String o2) {
    		return o1.toString().compareTo(o2.toString());
    	}
    });
    sortedSet.addAll(set);

## 4、用TreeMap对map排序 ##

### （1）、 ###

Map<String, Integer> map = new HashMap<>();
    map.put("Clinton",1995);
    map.put("Bush",2000);
    map.put("Trump",2016);
    map.put("Plata",2005);
    Map<String, Integer> sortedMap = new TreeMap<String, Integer>(String.CASE_INSENSITIVE_ORDER);
    sortedMap.putAll(map);

**结果**：\{Bush=2000, Clinton=1995, Plata=2005, Trump=2016\}

### （2）、 ###

Map<String, Integer> map = new HashMap<>();
    map.put("Clinton",1995);
    map.put("Trump",2016);
    map.put("Plata",2005);
    map.put("Bush",2000);
    Map<String, Integer> sortedMap = new TreeMap<String, Integer>(new Comparator<String>() {
     @Override
     public int compare(String o1, String o2) {
     return o1.toString().compareTo(o2.toString());
     }
    });
    sortedMap.putAll(map);

**结果**：\{Bush=2000, Clinton=1995, Plata=2005, Trump=2016\}