Java8 用Lambda表达式给List集合排序的实现

public class Apple {  private int weight;  private String color;  public Apple(){}  public Apple(int weight) {    this.weight = weight;  }  public Apple(int weight, String color) {    this.weight = weight;    this.color = color;  }    setters();getters();toString(); }

public class AppleComparator implements Comparator<Apple> {  @Override  public int compare(Apple o1, Apple o2) {    return o1.getWeight() - o2.getWeight();  }}

ArrayList<Apple> inventory = Lists.newArrayList(        new Apple(10, "red"),        new Apple(5, "red"),        new Apple(1, "green"),        new Apple(15, "green"),        new Apple(2, "red"));

/** * 顺序排序 */// 1、传递代码，函数式编程inventory.sort(new AppleComparator());System.out.println(inventory);// 2、匿名内部类inventory.sort(new Comparator<Apple>() {  @Override  public int compare(Apple o1, Apple o2) {    return o1.getWeight() - o2.getWeight();  }});// 3、使用Lambda表达式inventory.sort((a, b) -> a.getWeight() - b.getWeight());// 4、使用Comparator的comparingComparator<Apple> comparing = comparing((Apple a) -> a.getWeight());inventory.sort(comparing((Apple a) -> a.getWeight()));//或者等价于inventory.sort(comparing(Apple::getWeight));

/** * 逆序排序 */// 1、 根据重量逆序排序inventory.sort(comparing(Apple::getWeight).reversed()); 

// 2、如果两个苹果的重量一样重，怎么办？那就再找一个条件进行排序呗inventory.sort(comparing(Apple::getWeight).reversed().thenComparing(Apple::getColor));