功能性的方式下面是我试图转换成函数式编程代码一些必要的代码:积累对在java8
public class Person {
String name;
Token token;
public Person(String name, Token token) {
this.name = name;
this.token = token;
}
}
public class Token {
String id;
boolean isValid;
public Token(String id, boolean isValid) {
this.id = id;
this.isValid = isValid;
}
public String getId() { return id; }
public boolean isValid() {return isValid;}
}
public static List<Token> getTokensForPerson(String name) {...}
public static List<Person> getPeople1 (String[] names) {
List<Person> people = new ArrayList<Person>();
for (String name: names) {
List<Token> tokens = getTokensForPerson(name);
for (Token token: tokens) {
if (token.isValid()) {
people.add(new Person(name, token));
}
}
}
return people;
}
这是我尝试做了功能性的方式。
public static List<Person> getPeople2 (String[] names) {
return Arrays.stream(names).map(name -> getTokensForPerson(name))
.flatMap(tokens -> tokens.stream().filter(token -> token.isValid))
.map(token -> new Person(name, token)) // <== compiler error here. "Cannot resolve symbol 'name'"
.collect(Collectors.toList());
}
但是它不会编译,因为在过去的地图操作我需要参考name
创建Person
对象,name
不可在那个时候。有任何想法吗?
的 “当务之急” 是更好:) – ZhongYu