如何用新的1.8stream API连接字符串[重复]

Question

public String concantAndReturnNames(final Collection<Person> persons) {
    String result = "";
    for (Person person : persons) {
        result += person.getName();
    }
    return result;
}

Answer 1

您想要做的事情的官方文档：https://docs.oracle.com/javase/8/docs/api/java/util/stream/collectors.html

 // Accumulate names into a List
 List<String> list = people.stream().map(Person::getName).collect(Collectors.toList());

 // Convert elements to strings and concatenate them, separated by commas
 String joined = things.stream()
                       .map(Object::toString)
                       .collect(Collectors.joining(", "));

对于您的示例，您需要这样做：

 // Convert elements to strings and concatenate them, separated by commas
 String joined = persons.stream()
                       .map(Person::getName) // This will call person.getName()
                       .collect(Collectors.joining(", "));

传递给collectors的参数。联接是可选的。