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 jangle@jangle.xyz
* @time 2020年9月4日 下午4:04:05
*
*/
public class M {
public static void main(String[] args) {
List<Double> 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<Person> 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 jangle@jangle.xyz
* @time 2020年9月1日 下午6:03:57
*
*/
public class Person implements Comparable<Person> {
private int id;
private String firstName, lastName;
private Date birthDate;
private int salary;
private double coeficient;
private static Comparator<Person> 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
