commons双向Map和Bag包

双向Map

import org.apache.commons.collections4.BidiMap;
import org.apache.commons.collections4.MapIterator;
import org.apache.commons.collections4.bidimap.DualHashBidiMap;
import org.apache.commons.collections4.bidimap.DualTreeBidiMap;


/**BidiMap
 * 双向Map->要求键与值都不能重复
 * 可以通过键找值,也可以通过值找键->inverseBidiMap()反转 
 * 1.DualTreeBidiMap :有序
 * 2.DualHashBidiMap :无序
 */

public class Demo05 {
    public static void main(String[] args) {
        test1();
        test2();
    }

    public static void test2(){
        System.out.println("=====有序的双向Map====");
        BidiMap<String,String> map =new DualTreeBidiMap<String,String>();
        map.put("bj", "bj@test.com");
        map.put("sxt", "sxt@qq.com");   
        //遍历查看
        MapIterator<String,String> it =map.inverseBidiMap().mapIterator();
        while(it.hasNext()){
            String key =it.next();
            String value =it.getValue();
            System.out.println(key+"-->"+value);
        }
    }

    public static void test1(){
        BidiMap<String,String> map = new DualHashBidiMap<String,String>();
        map.put("bj", "bj@test.com");
        map.put("sxt", "sxt@qq.com");
        System.out.println(map.inverseBidiMap().get("sxt@qq.com"));
        //反转
        System.out.println(map.inverseBidiMap().get("sxt@qq.com"));
        //遍历查看
        MapIterator<String,String> it =map.inverseBidiMap().mapIterator();
        while(it.hasNext()){
            String key =it.next();
            String value =it.getValue();
            System.out.println(key+"-->"+value);
        }
    }
}

Bag包

import java.util.Iterator;
import java.util.Set;

import org.apache.commons.collections4.Bag;
import org.apache.commons.collections4.bag.HashBag;
import org.apache.commons.collections4.bag.TreeBag;

/**
 * Bag包->允许重复
 * 1.HashBag 无序
 * 2.TreeBag 有序
 * 3.统计单词的出现次数
 */
public class Demo06 {
    public static void main(String[] args) {
        test1();
        test2();
        test3();
    }

    public static void test1(){
        System.out.println("=========无序的=========");
        Bag<String> bag = new HashBag<>();
        bag.add("a");
        bag.add("a",5);
        bag.remove("a", 2);
        bag.add("b");
        bag.add("c");
        Iterator<String> it =bag.iterator();
        while(it.hasNext()){
            System.out.println(it.next());
        }
    }

    public static void test2(){
        System.out.println("=========有序的=========");    
        Bag<String> bag = new TreeBag<>();
        bag.add("a");
        bag.add("a",5);
        bag.remove("a", 2);
        bag.add("b");
        bag.add("c");
        Iterator<String> it =bag.iterator();
        while(it.hasNext()){
            System.out.println(it.next());
        }
    }

    public static void test3(){
        String str = "this is a cat and that is a mice where is the food ";
        String[] arr = str.split(" ");
        Bag<String> bag = new HashBag<>();
        for(String temp:arr){
            bag.add(temp);
        }

        Set<String> set = bag.uniqueSet();
        for(String letter:set){
            System.out.println(letter+"--"+bag.getCount(letter));
        }
    }
}