46.函数式接口

@FunctionalInterface
public interface FunctionInterface {
    void show();
}

public class Demo {
    public static void main(String[] args) {
        startThread(new Runnable() {
            @Override
            public void run() {
                System.out.println(Thread.currentThread().getName() + "启动一个线程");
            }
        });
        startThread(() -> System.out.println(Thread.currentThread().getName() + "启动一个线程"));
    }

    public static void startThread(Runnable runnable) {
        Thread thread = new Thread(runnable);
        thread.start();
    }
}

    public static Comparator<String> getComparator() {
//        return new Comparator<String>() {
//            @Override
//            public int compare(String s1, String s2) {
//                return s1.length()-s2.length();
//            }
//        };
        return (s1,s2)->s1.length()-s2.length();
    }
        //      将下面集合中的字符串按照长度排序
        ArrayList<String> list = new ArrayList<>();
        list.add("aaa");
        list.add("aaaaa");
        list.add("aaaaaa");
        list.add("aaaa");
        System.out.println("排序之前:"+list);//[aaa, aaaaa, aaaaaa, aaaa]
        Collections.sort(list,getComparator());
        System.out.println("排序之后:"+list);//[aaa, aaaa, aaaaa, aaaaaa]

public class Demo2 {
    public static void main(String[] args) {
        String str = getStr(new Supplier<String>() {
            @Override
            public String get() {
                return "字符串";
            }
        });
        System.out.println(str);
        String str1 = getStr(() -> "字符串");
        System.out.println(str1);
    }

    public static String getStr(Supplier<String> supplier) {
        return supplier.get();
    }
}

    public static Integer getMax(Supplier<Integer> supplier) {
        return supplier.get();
    }
        int []num={15,55,88,33,66};
        Integer max = getMax(new Supplier<Integer>() {
            @Override
            public Integer get() {
                int max = num[0];
                for (int i = 0; i < num.length; i++) {
                    if (num[i] > max) {
                        max = num[i];
                    }
                }
                return max;
            }
        });
        Integer max1 = getMax(() -> {
            int maxValue = num[0];
            for (int i = 0; i < num.length; i++) {
                if (num[i] > maxValue) {
                    maxValue = num[i];
                }
            }
            return maxValue;
        });
        System.out.println(max);
        System.out.println(max1);