Java使用stream將List轉為Map

需求

從List對象列表提取2個字段，分別作為Map的key-value

實現

public static void main( String[] args )
{
    ArrayList<Person> list = new ArrayList<>();
    list.add(new Person(1,"張三",20, 1));
    list.add(new Person(2,"李四",23, 0));
    list.add(new Person(3,"王五",22, 1));
    list.add(new Person(4,"趙六",25, 1));

    Map<Integer, String> map = list
                .stream()
                .collect(Collectors.toMap(p -> p.getId(), p -> p.getName()));
    System.out.println(map);
}

輸出結果如下：{1=張三, 2=李四, 3=王五, 4=趙六}