Java://Comparator、Comparable的用法(按照要求将set集合的数据进行排序输出):

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

//comparator、comparable的用法(按照要求将map集合的键值对进行顺序输出)

import java.util.List;

public class Test

{

public static <T> void sop(T t)

{

System.out.PRintln(t);

}

public static void main(String args[]) throws Exception

{

// 创建一个map集合,用来存储数据 <>表示接收的是泛型,即指定的类型

List<Person> list = new ArrayList<Person>();

// 往集合添加数据

list.add(new Person("czhangsan1", "11", "beijing"));

list.add(new Person("zhangsan5", "15", "nanjing"));

list.add(new Person("azhangsan5", "10", "shanghai"));

list.add(new Person("zhangsan2", "20", "haierbing"));

list.add(new Person("bzhangsan2", "20", "beijing"));

list.add(new Person("zhangsan3", "12", "shanghai"));

list.add(new Person("zhangsan4", "19", "changchun"));

list.add(new Person("zhangsan4", "10", "changchun"));

list.add(new Person("zhangsan4", "10", "zhengzhou"));

// 将map集合转换为set集合,因为map集合没有迭代器 ，而set集合有

Collections.sort(list);

System.out.println("按年龄排序：");

for (Person person : list)

{

System.out.println(person.toString());

}

Collections.sort(list, new MyCompare());

System.out.println("按姓名排序：");

for (Person person : list)

{

System.out.println(person.toString());

}

}

}

class Person implements Comparable<Person>// 使Person的属性具有比较性

{

private String name;

private String age;

private String address;

public Person(String name, String age, String address)// 初始化

{

this.name = name;

this.age = age;

this.address = address;

}

public String getName()

{

return name;

}

public void setName(String name)

{

this.name = name;

}

public String getAge()

{

return age;

}

public void setAge(String age)

{

this.age = age;

}

public String getAddress()

{

return address;

}

public void setAddress(String address)

{

this.address = address;

}

@Override

public String toString()

{

return "姓名：" + name + ", 年龄：" + age + ", 地址：" + address;

}

// 按年龄大小排序规则

@Override

public int compareTo(Person o)

{

return this.age.compareTo(o.getAge());

}

}

// 按姓名字典顺序排序

class MyCompare implements Comparator<Person>// 自定义一个比较器

{

@Override

public int compare(Person o1, Person o2)

{

return o1.getName().compareTo(o2.getName());

}

}

// 注意：上面的两种形式都实现了比较,任选其中一种就可以。要么实现comparable接口；要么在集合中传入自定义的比较器。