随手记：Map.ketSet()

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对同一个map取keySet()得到的结果相同，用equals和==得到的都是true

/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */package map;import java.util.LinkedHashMap;import java.util.Set;/** *对同一个map取keySet()得到的结果相同，用equals和==得到的都是true * @author Jq */public class MapTestMain {        private void mapTest() {LinkedHashMap<Integer, String> testMap = new LinkedHashMap<>();testMap.put(1, "one");testMap.put(2, "two");testMap.put(3, "three");Set keySet_1 = testMap.keySet();Set keySet_2 = testMap.keySet();System.out.println("Equals:" + keySet_1.equals(keySet_2));System.out.println("==: " + (keySet_1 == keySet_2));    }    /**     * @param args the command line arguments     */    public static void main(String[] args) {MapTestMain test = new MapTestMain();test.mapTest();    }    }

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