对象按照某属性升序，降序

只是写了按照对象里面的id排序，如果按照其余的字段升降序也可以实现。

/**
 * 个人信息排序
 * @author wWX154783
 * 
 */
public class PersonSort
{
    public static void main(String[] args)
    {
        List<Person> list = new ArrayList<Person>();
        for (int i = 0; i < 10; i++)
        {
            Person person = new Person();
            person.setId(new Random().nextInt(50));
            list.add(person);
        }
        System.out.println("原始:\t" + list);

        Collections.sort(list, new PersonOrderByIdAsc());
        System.out.println("升序:\t" + list);

        Collections.sort(list, new PersonOrderByIdDesc());
        System.out.println("降序:\t" + list);
    }
}

/* 人 */
class Person implements Comparator<Person>
{
    private int id;
    private int age;
    private String name;
    private String sex;
    private String address;

    public int compare(Person o1, Person o2)
    {
        return 0;
    }

    public int getId()
    {
        return id;
    }

    public void setId(int id)
    {
        this.id = id;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }

    public int getAge()
    {
        return age;
    }

    public void setAge(int age)
    {
        this.age = age;
    }

    public String getSex()
    {
        return sex;
    }

    public void setSex(String sex)
    {
        this.sex = sex;
    }

    public String getAddress()
    {
        return address;
    }

    public void setAddress(String address)
    {
        this.address = address;
    }

    @Override
    public String toString()
    {
        return "id=" + this.id;
    }

}

/* 按照person id升序 */
class PersonOrderByIdAsc extends Person
{
    @Override
    public int compare(Person o1, Person o2)
    {
        if (o1.getId() > o2.getId())
        {
            return 1;
        }
        else if (o1.getId() < o2.getId())
        {
            return -1;
        }
        else
        {
            return 0;
        }
    }
}

/* 按照person id降序 */
class PersonOrderByIdDesc extends Person
{
    @Override
    public int compare(Person o1, Person o2)
    {
        if (o1.getId() < o2.getId())
        {
            return 1;
        }
        else if (o1.getId() > o2.getId())
        {
            return -1;
        }
        else
        {
            return 0;
        }
    }
}