每日一经

每天收集一个java日常能用到的解决问题的方法，以后方便查阅。

实现

java8环境，使用了Arrays.sort和lambda表达式：

/**
 * 瓜类：
 * 类型和重量
 */
public class Melon {
    private String type;
    private Integer weight;

    public Melon(String type, int weight) {
        this.type = type;
        this.weight = weight;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public int getWeight() {
        return weight;
    }

    public void setWeight(Integer weight) {
        this.weight = weight;
    }
}

排序

Melon[] melons = new Melon[3];
        melons[0] = new Melon("1 melon", 1);
        melons[1] = new Melon("10 melon", 10);
        melons[2] = new Melon("5 melon", 5);
        // before
        for (Melon melon: melons) {
            System.out.println(melon.getType());
        }
        // asc sort
        Arrays.sort(melons, (Melon melon1, Melon melon2)
                -> Integer.compare(melon1.getWeight(), melon2.getWeight()));
        // after
        for (Melon melon: melons) {
            System.out.println(melon.getType());
        }

        // desc sort
        Arrays.sort(melons, (Melon melon1, Melon melon2)
                -> Integer.compare(melon2.getWeight(), melon1.getWeight()));
        // after
        for (Melon melon: melons) {
            System.out.println(melon.getType());
        }