/**   * @Description: 分组工具类   *   * @Author: hepengfei   * @Date: 15:43 2018/3/20   */public class GroupUtils {     /**      * eg:      * List list = devider(list, (Apple o1, Apple o2) -> {      *      return o1.getWeight() == o2.getWeight() ?0 : 1;      * });      * @param datas 带分组的list      * @param c      * @param 
    
           * @return      */    public static 
     
       List
      
       
        > devider(Collection
        
          datas, Comparator
          c){        List
         
          
           > result = new ArrayList
           
            
             >(); for (T t : datas) { boolean isSame = false; for (int i=0;i
             
               innerList = new ArrayList
              
               (); result.add(innerList); innerList.add(t); } } return result; } /** demo */ public void test(List list){ List devider = devider(list, (Apple o1, Apple o2) -> { return o1.getWeight() == o2.getWeight() ?0 : 1; }); System.out.println(devider); } class Apple{ private int weight; public int getWeight() { return weight; } public void setWeight(int weight) { this.weight = weight; } }}
              
             
            
           
          
         
        
       
      
     
    

2.Comparable,Comparator

Comparable是为了对某个类的集合进行排序，所以此时一般都是这个需要排序的类本身去实现Comparable接口;倘若我们要根据其他规则排序,可以匿名内部类或者lambda表达式使用Comparator接口:        list.sort(Comparator.comparing(Employee::getSalary).thenComparing(Employee::getName));