sort By Key in Map - Java Collection Framework

Java examples for Collection Framework:Map

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Description

sort By Key in Map

Demo Code


//package com.java2s;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;

import java.util.LinkedList;
import java.util.List;
import java.util.Map;

public class Main {
    public static <K extends Comparable<? super K>, V> Map<K, V> sortByKey(
            Map<K, V> map) {
        List<Map.Entry<K, V>> list = new LinkedList<Map.Entry<K, V>>(
                map.entrySet());/*from www .j ava 2 s . c o  m*/
        Collections.sort(list, new Comparator<Map.Entry<K, V>>() {
            public int compare(Map.Entry<K, V> o1, Map.Entry<K, V> o2) {
                return (o1.getKey()).compareTo(o2.getKey());
            }
        });

        Map<K, V> result = new HashMap<K, V>();
        for (Map.Entry<K, V> entry : list) {
            result.put(entry.getKey(), entry.getValue());
        }
        return result;
    }
}

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