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之前栈长分享过 Java 8 一系列新特性的文章，其中重点介绍了 Stream。
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今天来分享下在 Java 8 中创建 Stream 的 10 种方式，我就整理了 10 种，其实还有更多，仅供大家参考学习下。
1、Stream.of 可变参数
Stream<String> stream1 = Stream.of("A", "B", "C");System.out.println("stream1:" + stream1.collect(joining()));of("A", "B", "C");
System.out.println("stream1:" + stream1.collect(joining()));
程序输出：
stream1:ABC
2、Stream.of 数组
String[] values = new String[]{"A", "B", "C"};Stream<String> stream2 = Stream.of(values);System.out.println("stream2:" + stream2.collect(joining()));new String[]{"A", "B", "C"};
Stream<String> stream2 = Stream.of(values);
System.out.println("stream2:" + stream2.collect(joining()));
程序输出：
stream2:ABC
看 Stream.of 源码，上面这两种方式其实就是第三种方式的包装版。
public static<T> Stream<T> of(T... values) { return Arrays.stream(values);}
return Arrays.stream(values);
}
我们直接使用源码中的方式也是一样的。
3、Arrays.stream
String[] values = new String[]{"A", "B", "C"};Stream<String> stream3 = Arrays.stream(values);System.out.println("stream3:" + stream3.collect(joining()));new String[]{"A", "B", "C"};
Stream<String> stream3 = Arrays.stream(values);
System.out.println("stream3:" + stream3.collect(joining()));
程序输出：
stream3:ABC
4、List
List<String> list = Arrays.asList("A", "B", "C");Stream<String> stream4 = list.stream();System.out.println("stream4:" + stream4.collect(joining()));list = Arrays.asList("A", "B", "C");
Stream<String> stream4 = list.stream();
System.out.println("stream4:" + stream4.collect(joining()));
程序输出：
stream4:ABC
5、Set
Set<String> set = new HashSet<>(Arrays.asList("A", "B", "C"));Stream<String> stream5 = set.stream();System.out.println("stream5:" + stream5.collect(joining()));String> set = new HashSet<>(Arrays.asList("A", "B", "C"));
Stream<String> stream5 = set.stream();
System.out.println("stream5:" + stream5.collect(joining()));
程序输出：
stream5:ABC
6、Map
Map<String, String> map = new HashMap<>();map.put("1", "A");map.put("2", "B");map.put("3", "C");Stream<String> stream6 = map.values().stream();System.out.println("stream6:" + stream6.collect(joining()));new HashMap<>();
map.put("1", "A");
map.put("2", "B");
map.put("3", "C");
Stream<String> stream6 = map.values().stream();
System.out.println("stream6:" + stream6.collect(joining()));
程序输出：
stream6:ABC
7、Stream.iterate
Stream<String> stream7 = Stream.iterate("A", e -> String.valueOf((char) (e.charAt(0) + 1))).limit(3);System.out.println("stream7:" + stream7.collect(joining()));"A", e -> String.valueOf((char) (e.charAt(0) + 1))).limit(3);
System.out.println("stream7:" + stream7.collect(joining()));
程序输出：
stream7:ABC
8、Pattern
String value = "A B C";Stream<String> stream8 = Pattern.compile("\W").splitAsStream(value);System.out.println("stream8:" + stream8.collect(joining()));"A B C";
Stream<String> stream8 = Pattern.compile("\W").splitAsStream(value);
System.out.println("stream8:" + stream8.collect(joining()));
程序输出：
stream8:ABC
9、Files.lines
try { Stream<String> stream9 = Files.lines(Paths.get("d:/data.txt")); System.out.println("stream9:" + stream9.collect(joining()));} catch (IOException e) { e.printStackTrace();}
Stream<String> stream9 = Files.lines(Paths.get("d:/data.txt"));
System.out.println("stream9:" + stream9.collect(joining()));
} catch (IOException e) {
e.printStackTrace();
}
data.txt文件内容如下：
ABC
B
C
程序输出：
stream9:ABC
10、Stream.generate
Stream<String> stream10 = Stream.generate(() -> "A").limit(3);System.out.println("stream10:" + stream10.collect(joining()));"A").limit(3);
System.out.println("stream10:" + stream10.collect(joining()));
程序输出：
stream10:AAA
好了，这是栈长整理的 10 种创建 Stream 的方式，是不是很骚？如果你还知道其他的骚操作，可以留言告诉大家，让大家记住你的头像和ID。
转发分享一下吧，我保证你日后总有机会用得着的。
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