Collection#stream/parallelStream
Arrays#stream
Stream#of
BufferedReader#lines
Files.lines(Path)
Scanner#tokens (Java 9)
Random#ints
StreamSupport#stream
Pattern.complie(splitter)#splitAsStream
Stream#generate
Stateful: distinct, skip, sorted, [断路型]limit, takeWhile(Java9), dropWhile(Java9)
StateLess: filter, peek, map, flatMap
completion: forEach, reduce, collect