Stream + Lambda 用来处理、转换数据确实非常合适。
字符串转数字数组
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
public class Test {
public static void main(String[] args) {
String str = "1, 22, 7, 20, 101, 30";
List<Long> numbers = Arrays.stream(str.split(","))
.map(s -> Long.valueOf(s.trim()))
.filter(t -> t < 100)
.sorted()
.collect(Collectors.toList());
System.out.println(numbers);
// [1, 7, 20, 22, 30]
}
}
Reactor
Maven, 参考 reactor-by-example
<dependency>
<groupId>io.projectreactor</groupId>
<artifactId>reactor-core</artifactId>
<version>3.4.22</version>
</dependency>
样例 1
Flux
.range(3, 5) // 3, 4, 5, 6, 7
.map(t -> t + 1) // 4, 5, 6, 7, 8
.filter(t -> t % 2 == 0) // 4, 6, 8
.buffer(2) // [4, 6], [8]
.subscribe(System.out::println);// print [4,6] \n [8]
样例 2
flatMapIterable 将一个对象拆分为多个对象
Flux.just("hello_world_!")
.flatMapIterable(t -> Arrays.asList(t.split("_")))
.flatMap(t -> Flux.just("prefix_" + t))
.subscribe(System.out::println);
/*
prefix_hello
prefix_world
prefix_!
*/自定义 Publisher
public class Main {
public static void main(String[] args) {
Flux
.fromIterable(Arrays.asList("hello","world"))
.flatMap(t -> new TimePublisher(t))
.map(t -> {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String time = sdf.format(new Date());
return t + "_" + time;
})
.subscribe(System.out::println);
}
static class TimePublisher implements Publisher {
private String str;
private String time;
public TimePublisher(String s) {
this.str = s;
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
this.time = sdf.format(new Date());
}
@Override
public void subscribe(Subscriber subscriber) {
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
subscriber.onNext(this.time + "_" + this.str);
}
}
}
/*
2022-09-05 22:19:28_hello_2022-09-05 22:19:31
2022-09-05 22:19:31_world_2022-09-05 22:19:34
*/自定义异步 Publisher
- 将自定义 Publisher extends Mono
-
.flatMap(t -> new TimePublisher(t)) 同步触发
Thread[main,5,main]
2022-09-05 22:29:43_hello_2022-09-05 22:29:46
Thread[main,5,main]
2022-09-05 22:29:46_world_2022-09-05 22:29:49
Thread[main,5,main]
-
.flatMap(t -> new TimePublisher(t).subscribeOn(Schedulers.parallel())) 异步触发
Thread[parallel-1,5,main]
Thread[main,5,main]
Thread[parallel-2,5,main]
2022-09-05 22:31:00_world_2022-09-05 22:31:03
2022-09-05 22:31:00_hello_2022-09-05 22:31:03
具体实现
public class Main {
public static void main(String[] args) throws InterruptedException {
Flux
.fromIterable(Arrays.asList("hello","world"))
.flatMap(t -> new TimePublisher(t).subscribeOn(Schedulers.parallel()))
.map(t -> {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String time = sdf.format(new Date());
return t + "_" + time;
})
.subscribe(System.out::println);
System.out.println(Thread.currentThread());
Thread.sleep(10000);
}
static class TimePublisher extends Mono {
private String str;
private String time;
public TimePublisher(String s) {
this.str = s;
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
this.time = sdf.format(new Date());
}
@Override
public void subscribe(Subscriber subscriber) {
System.out.println(Thread.currentThread());
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
subscriber.onNext(this.time + "_" + this.str);
}
}
}
