使用分隔符加入字串
Version >= Java SE 8
可以使用靜態方法 String.join()
連線字串陣列 :
String[] elements = { "foo", "bar", "foobar" };
String singleString = String.join(" + ", elements);
System.out.println(singleString); // Prints "foo + bar + foobar"
同樣, Iterable
s 有一個過載的 String.join()
方法。
要對加入進行細粒度控制,可以使用 StringJoiner 類:
StringJoiner sj = new StringJoiner(", ", "[", "]");
// The last two arguments are optional,
// they define prefix and suffix for the result string
sj.add("foo");
sj.add("bar");
sj.add("foobar");
System.out.println(sj); // Prints "[foo, bar, foobar]"
要加入字串流,你可以使用加入收集器 :
Stream<String> stringStream = Stream.of("foo", "bar", "foobar");
String joined = stringStream.collect(Collectors.joining(", "));
System.out.println(joined); // Prints "foo, bar, foobar"
這裡還有一個定義字首和字尾的選項 :
Stream<String> stringStream = Stream.of("foo", "bar", "foobar");
String joined = stringStream.collect(Collectors.joining(", ", "{", "}"));
System.out.println(joined); // Prints "{foo, bar, foobar}"