stream 流使用

https://blog.csdn.net/weixin_43395106/article/details/113384464
https://blog.csdn.net/A_Gui_Code/article/details/106978867

demo1

        List<A> list = new ArrayList<>();
        list.add(new A() {{
            setCode(1);
            setName("鸣人");
        }});
        list.add(new A() {{
            setCode(2);
            setName("小樱");
        }});
        list.add(new A() {{
            setCode(1);
            setName("佐助");
        }});
        list.add(new A() {{
            setCode(2);
            setName("雏田");
        }});
        // 根据指定字段 去重
        List<A> collect = list.stream().collect(
                Collectors.collectingAndThen(
                        Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(A::getCode))), ArrayList::new
                )
        );
        // 指定字段 合并（不完善）
        collect.forEach(a -> {
            list.forEach(duplicates -> {
                if (!a.equals(duplicates) && a.getCode().equals(duplicates.getCode()) && !a.getName().equals(duplicates.getName())) {
                    a.setName(a.getName() + duplicates.getName());
                }
            });
        });
        System.out.println(collect);