class MyClass {
    private String attr1;
    private String attr2;
    // 構造函數(shù)
    public MyClass(String attr1, String attr2) {
        this.attr1 = attr1;
        this.attr2 = attr2;
    }
    // getter 和 setter 省略...
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null || getClass() != obj.getClass())
            return false;
        MyClass other = (MyClass) obj;
        return attr1.equals(other.attr1) && attr2.equals(other.attr2);
    }
    @Override
    public int hashCode() {
        return attr1.hashCode() ^ attr2.hashCode();
    }
}
// 使用示例
List<MyClass> list = new ArrayList<>();
// 填充list...
Set<MyClass> set = new HashSet<>(list);
list.clear();
list.addAll(set); // 去重后的list

List<MyClass> distinctList = list.stream()
    .collect(Collectors.toCollection(LinkedHashSet::new))
    .stream()
    .collect(Collectors.toList());```

Map<String, MyClass> result = list.stream()
    .collect(Collectors.toMap(
        o -> o.getAttr1() + o.getAttr2(), // key generator
        Function.identity(), // value mapper
        (oldValue, newValue) -> oldValue // merge function
    ));
List<MyClass> distinctList = new ArrayList<>(result.values());

public class ListDistinct <T>{
    /**
     * 通過set去重, 不打亂原有l(wèi)ist的順序
     *       list中相同的對象會被去重復
     *      
     * @param List<T> list
     * @return List<T>
     * */
    public List<T> distinctBySetOrder(List<T> list){
        Set<T> set = new  HashSet<T>(); 
        List<T> newList = new  ArrayList<T>(); 
        for (T t :list) {
           if(set.add(t)){
               newList.add(t);
           }
        }
        return newList;
    }
    /**
     * 通過set去重, 順序可能會亂
     *       list中相同的對象會被去重復
     *      
     * @param List<T> list
     * @return List<T>
     * */
    public List<T> distinctBySet(List<T> list){
        return new ArrayList<T>(new HashSet<T>(list));
    }
    /**
     * 通過遍歷判斷后將賦予新的集合
     * 
     * @param List<T>
     * @reutrn List<T>
     * */
    public List<T> distinctByANewList(List<T> list){
        List<T> newList = new  ArrayList<T>(); 
        for(T t : list){
            if(!newList.contains(t)){
                newList.add(t);
            }
        }
        return newList;
    }
    public static void main(String[] args){
        ListDistinct<String> ld = new ListDistinct<String>();
        List<String> list  =   new  ArrayList<String>(); 
        list.add("zhang");
        list.add("zhang");
        list.add("ss");
        list.add("ss");
        list.add("2s");
        list.add("s3");
        System.out.println("1:" + ld.distinctBySetOrder(list).toString());
        System.out.println("2:" + ld.distinctBySet(list).toString());
        System.out.println("3:" + ld.distinctByANewList(list).toString());
    }
}