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java Multimap

实现

{    "a": [        1,        2,        3    ],    "b": [        3,        7    ]}

当然, HashMap<String, List<Integer>> 是可以的,但是不方便。这里使用Multimap

举例

package com.example.ch6_2;import java.util.Collections;import com.google.common.collect.ArrayListMultimap;import com.google.common.collect.Multimap;public class testMultimap {    public static void main(String[] argv) {        Multimap<String, String> myMultiMap = ArrayListMultimap.create();        myMultiMap.put("Fruits", "Apple");        myMultiMap.put("Fruits", "Pear");        myMultiMap.put("Fruits", "Banana");        myMultiMap.put("Vegetables", "eggplant");        System.out.println("\nmyMultiMap size:" + myMultiMap.size());        System.out.println("\nmyMultiMap.get(Fruits): " + myMultiMap.get("Fruits"));        System.out.println("\nmyMultiMap.get(Vegetables): " + myMultiMap.get("Vegetables"));        System.out.println("\nkeys:");        for (String key : myMultiMap.keys()) {            System.out.println(key);        }        System.out.println("\nvalues:");        for (String value : myMultiMap.values()) {            System.out.println(value);        }        myMultiMap.remove("Fruits", "Apple");        System.out.println("\nmyMultiMap size:" + myMultiMap.size());        myMultiMap.removeAll("Fruits");        System.out.println("\nmyMultiMap size:" + myMultiMap.size());    }}

结果

myMultiMap size:4myMultiMap.get(Fruits): [Apple, Pear, Banana]myMultiMap.get(Vegetables): [eggplant]keys:VegetablesFruitsFruitsFruitsvalues:eggplantApplePearBananamyMultiMap size:3myMultiMap size:1

  

java Multimap