Map<String, String> map = new HashMap<>(); // Convert all Map keys to a List List<String> result = new ArrayList(map.keySet()); // Convert all Map values to a List List<String> result2 = new ArrayList(map.values()); // Java 8, Convert all Map keys to a List List<String>...
Example 1: Convert Map to List import java.util.*; public class MapList { public static void main(String[] args) { Map<Integer, String> map = new HashMap<>(); map.put(1, "a"); map.put(2, "b"); map.put(3, "c"); map.put(4, "d"); map.put(5, "e"); List<Integer...
import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.stream.Collectors; 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(...
publicMap<Integer, Animal>convertListWithGuava(List<Animal> list){ Map<Integer, Animal> map = Maps .uniqueIndex(list, Animal::getId);returnmap; }Copy Finally, we test the conversion: @TestpublicvoidgivenAList_whenConvertWithGuava_thenReturnMapWithTheSameElements(){ Map<Integer, Animal> map = c...
### 实现convertMap方法 下面是一个简单的实现,我们将展示如何将一个`Map<String, Integer>`转换为`Map<String, String>`,其中,Integer值会被转换为其字符串表示形式。 ```java import java.util.HashMap; import java.util.Map; import java.util.function.Function; public class MapConverter { /** * 将...
This Java tutorial will teachhow to convert Map keys and values to the array,ListorSet. Java maps are a collection of key-value pairs. TheMapkeys are always unique but can have duplicate values. 1. ConvertMaptoArray For demo purposes, let us create aMapwithStringkeys andIntegervalues. ...
Java 8 – Convert List to Map package com.mkyong.java8 public class Hosting { private int Id; private String name; private long websites; public Hosting(int id, String name, long websites) { Id = id; this.name = name; this.websites = websites; ...
SinceJava version 1.8, we can haveStreamsand collectors to convert aListinto aMapby usingtoMap()method. Map<Integer,Employee>employeeMap=uniqueEmployeeList.stream().collect(Collectors.toMap(Employee::id,Function.identity())); If we use duplicate employees list thentoMap()method riseIllegalStateExcept...
Stream map() to convert list of objects Let’s say we want to convert list of Subscriber objects to a list of User objects. Below are these two classespublic class Subscriber { private String sName; // getter and setter methods } public class User { private String uName; // getter and...
import java.util.Map; import java.util.concurrent.ConcurrentHashMap; /** * @Description: 基于BeanCopier的属性拷贝 * 凡是和反射相关的操作,基本都是低性能的。凡是和字节码相关的操作,基本都是高性能的 */ @Slf4j public class BeanCopyUtils { ...