LambdaのStream流

5、collector--streamストリームの要素を集める

 R collect(Collector super T, A, R> collector); Collector super T, A, R> collector      ，        。jdk8   Collector      Collectors        list 、set 、map 

例:

Book book = new Book("JAVA","ALIS", Book.Status.Busy,1009);
Book book2 = new Book("JAVASE","MARRY",Book.Status.Busy,393.234);
Book book3 = new Book("JAVAEE","LUCY",Book.Status.Free,3434.112);
Book book4 = new Book("MYBATIS","DANDAN",Book.Status.Busy,3423.12);

//名前を集めてリストに入れる

ArrayList books = new ArrayList<>();
books.add(book);
books.add(book2);
books.add(book3);
books.add(book4);

List collect = books.stream()
        .map(Book::getName)
        .collect(Collectors.toList());
System.out.println(collect);