package com.fancv; import java.util.ArrayList; import java.util.List; import java.util.Map; import java.util.stream.Collectors; public class MyTest { public static void main(String[] args) { List mydtoList= new ArrayList<>(2); mydto a = new mydto(); a.setId(102L); a.setName("a"); mydto b = new mydto(); b.setId(101L); b.setName("a"); mydtoList.add(a); mydtoList.add(b); Map d =mydtoList.stream().collect(Collectors.toMap(mydto::getName,mydto::getId)); } } class mydto { private String name; private Long id; public String getName() { return name; } public void setName(String name) { this.name = name; } public Long getId() { return id; } public void setId(Long id) { this.id = id; } }