enjoy = enjoys.stream().sorted(Comparator.comparing(GoodsEnjoy::getGroundingState, (s1, s2) -> { if (s1.equals(s2)) { return 0; } else if (s1 == 1 || s2 == 5) { return -1; } else if (s1 == 5 || s2 == 1) { return 1; } else if (s1 == 2) { return -1; } else if (s2 == 2) { return 1; } else if (s1 == 0) { return -1; } else { return 1; } })).findFirst().orElse(null);中怎么吧“{ if (s1.equals(s2)) { return 0; } else if (s1 == 1 || s2 == 5) { return -1; } else if (s1 == 5 || s2 == 1) { return 1; } else if (s1 == 2) { return -1; } else if (s2 == 2) { return 1; } else if (s1 == 0) { return -1; } else { return 1; } ”提为变量

可以将这段代码提取为一个lambda表达式或者一个匿名内部类，然后将其作为Comparator.comparing()方法的参数。示例代码如下：

Comparator<GoodsEnjoy> comparator = Comparator.comparing(
    GoodsEnjoy::getGroundingState,
    (s1, s2) -> {
        if (s1.equals(s2)) {
            return 0;
        } else if (s1 == 1 || s2 == 5) {
            return -1;
        } else if (s1 == 5 || s2 == 1) {
            return 1;
        } else if (s1 == 2) {
            return -1;
        } else if (s2 == 2) {
            return 1;
        } else if (s1 == 0) {
            return -1;
        } else {
            return 1;
        }
    }
);

GoodsEnjoy enjoy = enjoys.stream().sorted(comparator).findFirst().orElse(null);

这样可以让代码更加清晰易懂，也方便后续的维护和修改。

相关问题

enjoy = enjoys.stream().sorted(Comparator.comparing(GoodsEnjoy::getGroundingState, (s1, s2) -> { if (s1.equals(s2)) { return 0; } else if (s1 == 1 || s2 == 5) { return -1; } else if (s1 == 5 || s2 == 1) { return 1; } else if (s1 == 2) { return -1; } else if (s2 == 2) { return 1; } else if (s1 == 0) { return -1; } else { return 1; } })).findFirst().orElse(null);和 excellent = excellents.stream().sorted(Comparator.comparing(GoodsExcellent::getGroundingState, (s1, s2) -> { if (s1.equals(s2)) { return 0; } else if (s1 == 1 || s2 == 5) { return -1; } else if (s1 == 5 || s2 == 1) { return 1; } else if (s1 == 2) { return -1; } else if (s2 == 2) { return 1; } else if (s1 == 0) { return -1; } else { return 1; } })).findFirst().orElse(null);这简化一下

可以将这两段代码提取为一个通用的方法，然后复用该方法。示例代码如下：

private static <T, R extends Comparable<? super R>> T findFirstSorted(List<T> list, Function<T, R> keyExtractor) {
    Comparator<R> comparator = (s1, s2) -> {
        if (s1.equals(s2)) {
            return 0;
        } else if (s1 == 1 || s2 == 5) {
            return -1;
        } else if (s1 == 5 || s2 == 1) {
            return 1;
        } else if (s1 == 2) {
            return -1;
        } else if (s2 == 2) {
            return 1;
        } else if (s1 == 0) {
            return -1;
        } else {
            return 1;
        }
    };
    return list.stream().sorted(Comparator.comparing(keyExtractor, comparator)).findFirst().orElse(null);
}

GoodsEnjoy enjoy = findFirstSorted(enjoys, GoodsEnjoy::getGroundingState);
GoodsExcellent excellent = findFirstSorted(excellents, GoodsExcellent::getGroundingState);

这样可以让代码更加简洁，也方便后续的维护和修改。

enjoys.stream().sorted(Comparator.comparing(GoodsEnjoy::getGroundingState, (s1, s2) -> { if (s1.equals(s2)) { return 0; } else if (s1 == 1 || s2 == 5) { return -1; } else if (s1 == 5 || s2 == 1) { return 1; } else if (s1 == 2) { return -1; } else if (s2 == 2) { return 1; } else if (s1 == 0) { return -1; } else { return 1; } })).findFirst().orElse(null);将Comparator.comparing(GoodsEnjoy::getGroundingState, (s1, s2) -> { if (s1.equals(s2)) { return 0; } else if (s1 == 1 || s2 == 5) { return -1; } else if (s1 == 5 || s2 == 1) { return 1; } else if (s1 == 2) { return -1; } else if (s2 == 2) { return 1; } else if (s1 == 0) { return -1; } else { return 1; } })提为变量调用怎么改

你可以将Comparator.comparing(GoodsEnjoy::getGroundingState, (s1, s2) -> { if (s1.equals(s2)) { return 0; } else if (s1 == 1 || s2 == 5) { return -1; } else if (s1 == 5 || s2 == 1) { return 1; } else if (s1 == 2) { return -1; } else if (s2 == 2) { return 1; } else if (s1 == 0) { return -1; } else { return 1; } })提为一个变量，例如：

Comparator<GoodsEnjoy> comparator = Comparator.comparing(GoodsEnjoy::getGroundingState, (s1, s2) -> {
if (s1.equals(s2)) {
return 0;
} else if (s1 == 1 || s2 == 5) {
return -1;
} else if (s1 == 5 || s2 == 1) {
return 1;
} else if (s1 == 2) {
return -1;
} else if (s2 == 2) {
return 1;
} else if (s1 == 0) {
return -1;
} else {
return 1;
}
});

然后可以在排序中使用这个变量，例如：

enjoys.stream().sorted(comparator).findFirst().orElse(null);

这样就能达到将Comparator提为变量的目的了。