java8Examples/Java8Examples/src/map/ConvertListToMap.java at master · suatoz/java8Examples · GitHub

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package map;

import java.util.ArrayList;

import java.util.Comparator;

import java.util.LinkedHashMap;

import java.util.List;

import java.util.Map;

import java.util.stream.Collector;

import java.util.stream.Collectors;

import dataclasses.Hosting;

public class ConvertListToMap {

public static List<Hosting> list = new ArrayList<Hosting>();

static {

list.add(new Hosting(1, "liquidweb.com", 80000));

list.add(new Hosting(2, "linode.com", 90000));

list.add(new Hosting(3, "digitalocean.com", 120000));

list.add(new Hosting(4, "aws.amazon.com", 200000));

list.add(new Hosting(5, "mkyong.com", 1));

}

public static void main(String[] args) {

listToMap();

duplicatedKey();

sortAndCollect();

}

public static void listToMap() {

Map<Integer, String> resut1 = list.stream().collect(Collectors.toMap(Hosting::getId, Hosting::getName));

print(resut1);

Map<String, Long> result2 = list.stream().collect(Collectors.toMap(Hosting::getName, Hosting::getWebsites));

print(result2);

Map<String, Integer> result3 = list.stream().collect(Collectors.toMap(x -> x.getName(), x -> x.getId()));

print(result3);

}

public static void duplicatedKey() {

list.add(new Hosting(6, "linode.com", 100000)); // new line

//oldVal<>newVal deðiþebilir

Map<String,Long> result1 = list.stream().collect(Collectors.toMap(Hosting::getName,Hosting::getWebsites, (oldVal,newVal)-> oldVal));

print(result1);

}

public static void sortAndCollect() {

Map result = list.stream().sorted(Comparator.comparingLong(Hosting::getWebsites).reversed()).collect(Collectors.toMap(

Hosting::getName,Hosting::getWebsites,(oldVal,newVal) -> oldVal,LinkedHashMap::new

));

print(result);

}

private static void print(Map list) {

list.forEach((k,v)->{

System.out.println(k + " " + v);

});

System.out.println("<------------------------------------>");

}

java8Examples/Java8Examples/src/map/ConvertListToMap.java at master · suatoz/java8Examples · GitHub

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