java 集合

Posted 2020-08-23 jentary

List  用数组实现

 

Set  用链表实现

 

 

MAP 用数据加链表实现

 

map 输出

Map<String, String> map = new HashMap<String, String>();
        map.put("a", "1");
        map.put("b", "2");
        map.put("c", "3");
        
        Set<Map.Entry<String, String>> set2 = map.entrySet();
        /*
        for (Map.Entry<String, String> entry: map.entrySet()) {
            System.out.println(entry.getKey()+":"+entry.getValue());
        }*/
        
        List<Map.Entry<String, String>> list = new ArrayList<Map.Entry<String, String>>(set2);
        
        Collections.sort(list,new Comparator<Map.Entry<String, String>>(){

            public int compare(Entry<String, String> o1,
                    Entry<String, String> o2) {
                if(o1.getKey().compareTo(o2.getKey())>1){
                    return 1;
                }else if(o1.getKey().compareTo(o2.getKey())<1){
                    return -1;
                }
                return 0;
            }
            
        });
        
        for (Entry<String, String> entry : list) {
            System.out.println(entry.getKey()+":"+entry.getValue());
        }