本文介绍了Java:转换列表<字符串>到一个 join()d 字符串的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
JavaScript has Array.join()
js>["Bill","Bob","Steve"].join(" and ")
Bill and Bob and Steve
Does Java have anything like this? I know I can cobble something up myself with StringBuilder
:
static public String join(List<String> list, String conjunction)
{
StringBuilder sb = new StringBuilder();
boolean first = true;
for (String item : list)
{
if (first)
first = false;
else
sb.append(conjunction);
sb.append(item);
}
return sb.toString();
}
.. but there's no point in doing this if something like it is already part of the JDK.
解决方案
With Java 8 you can do this without any third party library.
If you want to join a Collection of Strings you can use the new String.join() method:
List<String> list = Arrays.asList("foo", "bar", "baz");
String joined = String.join(" and ", list); // "foo and bar and baz"
If you have a Collection with another type than String you can use the Stream API with the joining Collector:
List<Person> list = Arrays.asList(
new Person("John", "Smith"),
new Person("Anna", "Martinez"),
new Person("Paul", "Watson ")
);
String joinedFirstNames = list.stream()
.map(Person::getFirstName)
.collect(Collectors.joining(", ")); // "John, Anna, Paul"
The StringJoiner
class may also be useful.
这篇关于Java:转换列表<字符串>到一个 join()d 字符串的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!