并发编程：并行反应式流：遍历流（forEach,forEachOrdered）

目录

 

方法说明

一、主程序

二、辅助类

三、执行结果

---

方法说明

•  forEach()：无法保证动作是有序的应用到流上的。
•  forEachOrdered()：需要先使用sorted方法排序，再使用该方法，该方法可以保证动作是有序应用到流上的
•  peek()： 这是个中间操作，是懒执行的，只有调用结尾操作时，动作才会真正应用到流的消费元素上。

一、主程序

package xyz.jangle.thread.test.n6_5.foreach;

import java.util.List;

import xyz.jangle.thread.test.n6_2.create.Person;
import xyz.jangle.thread.test.n6_2.create.PersonGenerator;
import xyz.jangle.thread.test.n6_3.mapreduce.DoubleGenerator;

/**
 * 6.5、遍历流（forEach）
 *  forEach无法保证动作是有序的应用到流上的。
 *  forEachOrdered(): 需要先使用sorted方法排序，再使用该方法，该方法可以保证动作是有序应用到流上的
 *  peek(): 这是个中间操作，是懒执行的，只有调用结尾操作时，动作才会真正应用到流的消费元素上。
 * @author jangle
 * @email [email protected]
 * @time 2020年9月4日 下午4:04:05
 * 
 */
public class M {

	public static void main(String[] args) {
		List doubleList = DoubleGenerator.generateDoubleList(10, 100);
		System.out.println("**使用排序后的流来遍历：");
		doubleList.parallelStream().sorted().forEachOrdered(d -> System.out.println(d));
		System.out.println("**不使用排序遍历：");
		doubleList.parallelStream().sorted().forEach(d -> System.out.println(d));

		List persons = PersonGenerator.generatePersonList(10);
		System.out.println("**不使用排序遍历：");
		persons.parallelStream().forEach(p -> System.out.println(p.getLastName() + "," + p.getFirstName()));
		System.out.println("**使用排序后的流来遍历：");
		persons.parallelStream().sorted()
				.forEachOrdered(p -> System.out.println(p.getLastName() + "," + p.getFirstName()));

		doubleList.parallelStream().peek(d -> System.out.println("1 Step  :" + d))
				.peek(d -> System.out.println("2 Step :" + d)).forEach(d -> System.out.println("Last Step N:" + d));

	}

}

二、辅助类

DoubleGenerator：

https://blog.csdn.net/Bof_jangle/article/details/108372556

PersonGenerator:

https://blog.csdn.net/Bof_jangle/article/details/108350870

Person:

package xyz.jangle.thread.test.n6_2.create;

import java.util.Comparator;
import java.util.Date;

/**
 * 普通类，雇员信息
 * 
 * @author jangle
 * @email [email protected]
 * @time 2020年9月1日 下午6:03:57
 * 
 */
public class Person implements Comparable {

	private int id;
	private String firstName, lastName;
	private Date birthDate;
	private int salary;
	private double coeficient;

	private static Comparator comparator = Comparator.comparing(Person::getLastName)
			.thenComparing(Person::getFirstName);

	@Override
	public int compareTo(Person o) {

		/*
		 * int compareLastNames = this.getLastName().compareTo(o.getLastName()); if
		 * (compareLastNames != 0) { return compareLastNames; } else { return
		 * this.getFirstName().compareTo(o.getFirstName()); }
		 */
		return comparator.compare(this, o);

	}

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getFirstName() {
		return firstName;
	}

	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}

	public String getLastName() {
		return lastName;
	}

	public void setLastName(String lastName) {
		this.lastName = lastName;
	}

	public Date getBirthDate() {
		return birthDate;
	}

	public void setBirthDate(Date birthDate) {
		this.birthDate = birthDate;
	}

	public int getSalary() {
		return salary;
	}

	public void setSalary(int salary) {
		this.salary = salary;
	}

	public double getCoeficient() {
		return coeficient;
	}

	public void setCoeficient(double coeficient) {
		this.coeficient = coeficient;
	}

	@Override
	public String toString() {
		return firstName + " " + lastName;
	}

	@Override
	public boolean equals(Object obj) {
		if (obj instanceof Person) {
			return this.compareTo((Person) obj) == 0;
		} else {
			return false;
		}
	}

	@Override
	public int hashCode() {
		String sequence = this.getLastName() + this.getFirstName();
		return sequence.hashCode();
	}

}

三、执行结果

**使用排序后的流来遍历：
12.126256419681935
27.258965652231247
59.894337814749136
62.324808431739996
63.79242930792434
69.70840302146416
69.89499952458232
72.60540924733482
76.06770984905098
82.96765068330782
**不使用排序遍历：
69.89499952458232
82.96765068330782
63.79242930792434
59.894337814749136
72.60540924733482
76.06770984905098
27.258965652231247
69.70840302146416
12.126256419681935
62.324808431739996
**不使用排序遍历：
V,B
V,D
Z,G
X,C
T,B
W,A
X,E
Y,B
U,F
Y,D
**使用排序后的流来遍历：
T,B
U,F
V,B
V,D
W,A
X,C
X,E
Y,B
Y,D
Z,G
1 Step  :69.89499952458232
1 Step  :82.96765068330782
1 Step  :72.60540924733482
1 Step  :69.70840302146416
1 Step  :76.06770984905098
1 Step  :12.126256419681935
1 Step  :59.894337814749136
1 Step  :62.324808431739996
2 Step :59.894337814749136
2 Step :12.126256419681935
2 Step :76.06770984905098
2 Step :69.70840302146416
2 Step :72.60540924733482
2 Step :82.96765068330782
2 Step :69.89499952458232
Last Step N:82.96765068330782
Last Step N:72.60540924733482
Last Step N:69.70840302146416
Last Step N:76.06770984905098
Last Step N:12.126256419681935
Last Step N:59.894337814749136
2 Step :62.324808431739996
1 Step  :27.258965652231247
1 Step  :63.79242930792434
Last Step N:69.89499952458232
2 Step :63.79242930792434
2 Step :27.258965652231247
Last Step N:62.324808431739996
Last Step N:27.258965652231247
Last Step N:63.79242930792434