import java.util.Map; import java.util.stream.Collectors; public class TestDuplicatedKey { public static void main(String[] args) { List<Hosting> list = new ArrayList<>(); list.add(new Hosting(1, "liquidweb.com", 80000)); list.add(new Hosting(2, "linode.com", 90000)); list.add(n...
One of the common tasks in Java is to convert a List of objects, like aList<T>into a Map, I meanMap<K, V>, where K is some property of the object and V is the actual object. For example, suppose you have aList<Order>,and you want to convert it into a Map, e.g.Map<Order...
Here is the same result using nested loops and the map.merge method which is also Java 8. Map<String,String> map2 = new LinkedHashMap<>(); for (Order order : orders) { for (String eId : order.getExecutionId().split(",")) { map2.merge(eId, order.getOrderId(),...
Here is my code: List<Map<String, Object>> results = jdbcTemplate.queryForList(SQL, empId); Map<Integer, List<Integer>> resultMap =newHashMap<>(); List<Integer> tempLst =newArrayList<>();for(Map<String, Object> map : results) { tempLst.add(Integer.valueOf(map.get("DEPARTMENT_ID")....
Convert Map to List of Map.Entry<K,V> Convert Map to List using Two Lists Collectors.toList and Stream.map() Stream.filter() and Stream.sorted() Stream.flatMap() Convert Map to List of Map.Entry<K,V> Java 8 introduced us to the Stream API - which were meant as a step towards ...
at java.util.HashMap.merge(HashMap.java:1245) //... 2.2 To solve the duplicated key issue above, pass in the third mergeFunction argument like this : Map<String, Long> result1 = list.stream().collect( Collectors.toMap(Hosting::getName, Hosting::getWebsites, ...
import java.util.HashMap; import java.util.List; import java.util.Map; public class ConvertMapToList { public static void main(String[] args) { Map<Integer, String> map = new HashMap<>(); map.put(10, "apple"); map.put(20, "orange"); ...
import java.util.HashMap; import java.util.List; import java.util.Map; public class ConvertMapToList { public static void main(String[] args) { Map<Integer, String> map = new HashMap<>(); map.put(10, "apple"); map.put(20, "orange"); map.put(30, "banana"); map.put(40, "...
ConvertMapToList.java package com.mkyong; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class ConvertMapToList { public static void main(String[] args) { Map<Integer, String> map = new HashMap<>(); ...
importjava.util.HashMap; importjava.util.List; importjava.util.Map; importjava.util.stream.Collectors; classMain { // Generic method to convert `Map<K, V>` to a list of `<Map.Entry<K, V>` publicstatic<K,V>List<Map.Entry<K,V>>convertToList(Map<K,V>map) ...