方法一:根据java1.8lambda表达式进行排序
Comparator<RateInfo> comparator = (t1, t2) -> t1.getRateCode().compareTo(t2.getRateCode());
方法二:使用List的方法sort()排序
List API:default void
sort(Comparator<? super E> c)
其实也是依据Comarator这个类
rateInfolist.sort(comparator.reversed());
方法三:使用Collections类的sort进行排序
static <T> void
sort(List<T> list, Comparator<? super T> c)
Sorts the specified list according to the order induced by the specified comparator.
谷歌翻译:根据指定比较器引发的顺序对指定列表进行排序。
其实该排序也是使用
Comparator
类进行排序Comparator
类API:英文翻译即可int compare(T o1, T o2) Compares its two arguments for order. static <T,U extends Comparable<? super U>> Comparator<T> comparing(Function<? super T,? extends U> keyExtractor) Accepts a function that extracts a Comparable sort key from a type T, and returns a Comparator<T> that compares by that sort key. static <T,U> Comparator<T> comparing(Function<? super T,? extends U> keyExtractor, Comparator<? super U> keyComparator) Accepts a function that extracts a sort key from a type T, and returns a Comparator<T> that compares by that sort key using the specified Comparator. static <T> Comparator<T> comparingDouble(ToDoubleFunction<? super T> keyExtractor) Accepts a function that extracts a double sort key from a type T, and returns a Comparator<T> that compares by that sort key. static <T> Comparator<T> comparingInt(ToIntFunction<? super T> keyExtractor) Accepts a function that extracts an int sort key from a type T, and returns a Comparator<T> that compares by that sort key. static <T> Comparator<T> comparingLong(ToLongFunction<? super T> keyExtractor) Accepts a function that extracts a long sort key from a type T, and returns a Comparator<T> that compares by that sort key. boolean equals(Object obj) Indicates whether some other object is "equal to" this comparator. static <T extends Comparable<? super T>> Comparator<T> naturalOrder() Returns a comparator that compares Comparable objects in natural order. static <T> Comparator<T> nullsFirst(Comparator<? super T> comparator) Returns a null-friendly comparator that considers null to be less than non-null. static <T> Comparator<T> nullsLast(Comparator<? super T> comparator) Returns a null-friendly comparator that considers null to be greater than non-null. default Comparator<T> reversed() Returns a comparator that imposes the reverse ordering of this comparator. static <T extends Comparable<? super T>> Comparator<T> reverseOrder() Returns a comparator that imposes the reverse of the natural ordering. default Comparator<T> thenComparing(Comparator<? super T> other) Returns a lexicographic-order comparator with another comparator. default <U extends Comparable<? super U>> Comparator<T> thenComparing(Function<? super T,? extends U> keyExtractor) Returns a lexicographic-order comparator with a function that extracts a Comparable sort key. default <U> Comparator<T> thenComparing(Function<? super T,? extends U> keyExtractor, Comparator<? super U> keyComparator) Returns a lexicographic-order comparator with a function that extracts a key to be compared with the given Comparator. default Comparator<T> thenComparingDouble(ToDoubleFunction<? super T> keyExtractor) Returns a lexicographic-order comparator with a function that extracts a double sort key. default Comparator<T> thenComparingInt(ToIntFunction<? super T> keyExtractor) Returns a lexicographic-order comparator with a function that extracts a int sort key. default Comparator<T> thenComparingLong(ToLongFunction<? super T> keyExtractor) Returns a lexicographic-order comparator with a function that extracts a long sort key.
代码:
Collections.sort(rateInfolist, Comparator.comparing(RateInfo::getRateCode));
方法四:使用Comparator的匿名对象类重写compare方法
代码:
Collections.sort(rateInfolist, new Comparator<RateInfo>(){ /* * int compare(RateInfo R1, RateInfo R2) 返回一个基本类型的整型, * 返回负数表示:R1 小于R2, * 返回0 表示:R1和R2相等, * 返回正数表示:R1大于R2 */ public int compare(RateInfo R1, RateInfo R2) { Integer rateCode1 = Integer.parseInt(R1.getRateCode()); Integer rateCode2 = Integer.parseInt(R2.getRateCode()); //按照RateCode的年龄进行升序排列 if(rateCode1 > rateCode2){ return 1; } if(rateCode1 == rateCode2){ return 0; } return -1; } });
自己写代码时遇到的问题,根据我的理解和网上的资料做的总结