Stream流用于按照对象中某一属性来对集合去重+简单数据类型集合的去重

    //字符串集合进行简单的去重（其他数据类型去重一样）
        List<String> stringList = Arrays.asList("伽罗", "貂蝉", "芈月", "伽罗");
        //jdk1.8Stream来去重
        stringList = stringList.stream().distinct().collect(Collectors.toList());
        System.out.println(JSON.toJSONString(stringList));
        /**
         * 执行结果：["伽罗","貂蝉","芈月"]
         *
         */

/**
实体类
*/
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data//lombok简化代码
@AllArgsConstructor
@NoArgsConstructor
public class Hero {
    //英雄id
    private int id;
    //名字
    private String name;
    //类型
    private String type;
}

    //进行对象中的某个属性进行去重
        List<Hero> list = Arrays.asList(
                new Hero(001,"孙悟空","刺客"),
                new Hero(002,"韩信","刺客"),
                new Hero(003,"伽罗","射手"),
                new Hero(004,"阿狸","射手"),
                new Hero(005,"貂蝉","法师"));
        //需求：每一个职业只能保留一个英雄
        //去重规则，先出现的保存，后出现的被去掉
        list = list.stream()
                .collect(Collectors.collectingAndThen(
                        Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(Hero::getType))), ArrayList::new));
        System.out.println(JSON.toJSONString(list));
        /**
         * 执行结果：[{"id":1,"name":"孙悟空","type":"刺客"},{"id":3,"name":"伽罗","type":"射手"},
         * {"id":5,"name":"貂蝉","type":"法师"}]
         */