Collection中的接口：List、Set、SortedSet、Queue、第二篇

package com.set;

import java.util.HashSet;
import java.util.Set;
import java.util.TreeSet;

public class setdemo01 {
    public static void main(String[] args) {
        Set<String> allSet = new  HashSet<String>();//HashSet对输入的数据进行无序存放
        allSet.add("A");
        allSet.add("B");
        allSet.add("C");
        allSet.add("C");
        allSet.add("C");
        allSet.add("D");
        allSet.add("E");
        System.out.println(allSet);
        
        
    }

}

[D, E, A, B, C]

package com.set;


import java.util.Set;
import java.util.TreeSet;

public class setdemo01 {
    public static void main(String[] args) {
        
        Set<String> allSet = new  TreeSet<String>();//TreeSet对输入的数据进行有序存放
        allSet.add("B");
        allSet.add("E");
        allSet.add("C");
        allSet.add("C");
        allSet.add("A");
        allSet.add("C");
        allSet.add("D");
        System.out.println(allSet);
    }

}

[A, B, C, D, E]

package com.set;

import java.util.Set;
import java.util.TreeSet;
//自定义类排序，指定排序规则
class Person implements Comparable<Person>{
    private String name;
    private int age;
    
    public Person(String name,int age){
        this.name=name;
        this.age=age;
    }
    
    public String toString(){                //覆写ToString()方法
        return "姓名:"+this.name+";"+"年龄:"+this.age;
    }

    @Override
    public int compareTo(Person pp) {       //覆写compareTo()方法,指定排序规则
        if(this.age>pp.age){                //通过年龄排序
            return 1;
        }else if(this.age<pp.age){
            return -1;
        }else{
            return 0;
        }
        
    }
}

public class SetDemo02 {
    public static void main(String[] args) {
        Set<Person> allSet = new TreeSet<Person>();
        allSet.add(new Person("666",30));
        allSet.add(new Person("222",45));
        allSet.add(new Person("555",25));
        System.out.println(allSet);
    }

}

[姓名:555;年龄:25, 姓名:666;年龄:30, 姓名:222;年龄:45]

package com.set;

import java.util.HashSet;
import java.util.Set;

class Persons{
    private String name;
    private int age;
    
    public Persons(String name,int age){
        this.name=name;
        this.age=age;
    }
    
    public boolean equals(Object obj){
        if(this==obj){
            return true;
        }
        if(!(obj instanceof Persons)){
            return false;
        }
        Persons p=(Persons) obj;
        if(this.name.equals(p.name)&&this.age==p.age){
            return true;
        }else{
            return false;
        }
    }
    
    public int hashCode(){
        return this.name.hashCode()*this.age;
    }
    
    public String toString(){                //覆写ToString()方法
        return "姓名:"+this.name+";"+"年龄:"+this.age;
    }

}

public class SetDemo03 {
    public static void main(String[] args) {
        Set<Persons> allSet = new HashSet<Persons>();
        allSet.add(new Persons("666",30));
        allSet.add(new Persons("222",45));
        allSet.add(new Persons("555",25));
        allSet.add(new Persons("444",25));
        allSet.add(new Persons("333",25));
        allSet.add(new Persons("111",45));
        System.out.println(allSet);
    }

}

[姓名:111;年龄:45, 姓名:444;年龄:25, 姓名:333;年龄:25, 姓名:555;年龄:25, 姓名:222;年龄:45, 姓名:666;年龄:30]

package com.set;

import java.util.SortedSet;
import java.util.TreeSet;

public class SetDemo04 {
    public static void main(String[] args) {
        SortedSet<String> allSet = new TreeSet<String>();
        allSet.add("A");
        allSet.add("B");
        allSet.add("C");
        allSet.add("C");
        allSet.add("C");
        allSet.add("D");
        allSet.add("E");
        System.out.println("第一个元素:"+allSet.first());
        System.out.println("最后一个元素:"+allSet.last());
        System.out.println("从开始到指定元素的集合:"+allSet.headSet("C"));
        System.out.println("从指定元素到最后:"+allSet.tailSet("C"));
        System.out.println("返回指定对象间的元素:"+allSet.subSet("B","D"));
    }

}

第一个元素:A
最后一个元素:E
从开始到指定元素的集合:[A, B]
从指定元素到最后:[C, D, E]
返回指定对象间的元素:[B, C]