<div id="readability-page-1" class="page"><div><div><a rel="noopener" href="/@sindepal?source=post_page-----bf6b8ab3b8bb--------------------------------"><img alt="신상훈" src="https://miro.medium.com/fit/c/56/56/0*IyUJXQViJJEmVWaW.jpg" width="28" height="28"></a></div><h2 id="66b3">Comparator</h2><pre>package stream;import java.util.Arrays;import java.util.Comparator;import java.util.List;import java.util.function.Predicate;import java.util.stream.Collectors;class Course {private String name;private String category;private int reviewScore;private int noOfStudents;public Course(String name, String category, int reviewScore, int noOfStudents) {super();this.name = name;this.category = category;this.reviewScore = reviewScore;this.noOfStudents = noOfStudents;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getCategory() {return category;}public void setCategory(String category) {this.category = category;}public int getReviewScore() {return reviewScore;}public void setReviewScore(int reviewScore) {this.reviewScore = reviewScore;}public int getNoFoStudents() {return noOfStudents;}public void setNoOfStudents(int noFoStudents) {this.noOfStudents = noFoStudents;}@Overridepublic String toString() {return "Course [name=" + name + ", category=" + category + ", reviewScore=" + reviewScore + ", noFoStudents="+ noOfStudents + "]";}}public class FP04CustomClass {private static void println(String str) {System.out.println(str);}public static void main(String[] args) {List&lt;Course&gt; courses = Arrays.asList(new Course("Spring", "Freamework",99,25500),new Course("Spring Boot", "Freamework",67,26600),new Course("API", "Microservice",98,27700),new Course("Shin", "Name",78,20000),new Course("Kim", "Name",89,20990),new Course("RectJs", "Freamework",91,20000),new Course("Angular", "Freamework",75,20550),new Course("MariaDB", "Database",100,20044),new Course("MsSQL", "Database",94,20088),new Course("Oracle", "Database",83,23000),new Course("Lambda", "AWS",100,20033),new Course("EC2", "AWS",91,21220),new Course("CDk", "AWS",90,20110));Comparator&lt;Course&gt; comparatingByNoOfStudentsIncreasing = Comparator.comparing(Course::getNoFoStudents); System.out.println(courses.stream().sorted(comparatingByNoOfStudentsIncreasing).collect(Collectors.toList()));Comparator&lt;Course&gt; comparatingByNoOfStudentsDecreasing = Comparator.comparing(Course::getNoFoStudents).reversed();System.out.println(courses.stream().sorted(comparatingByNoOfStudentsDecreasing).collect(Collectors.toList())); Comparator&lt;Course&gt; comparatingByNoOfStudentsAndNoOfReviews = Comparator.comparing(Course::getNoFoStudents).thenComparing(Course::getReviewScore).reversed();System.out.println(courses.stream().sorted(comparatingByNoOfStudentsAndNoOfReviews).collect(Collectors.toList()));// comparingInt thenComparingInt...Comparator&lt;Course&gt; comparatingByNoOfStudentsAndNoOfReviews_2 = Comparator.comparingInt(Course::getNoFoStudents).thenComparingInt(Course::getReviewScore).reversed();System.out.println(courses.stream().sorted(comparatingByNoOfStudentsAndNoOfReviews).collect(Collectors.toList()));}}</pre></div></div>

Stories by 신상훈 on Medium

Comparator
package stream;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.function.Predicate;
import java.util.stream.Collectors;
class Course {
private String name;
private String category;
private int reviewScore;
private int noOfStudents;
public Course(String name, String category, int reviewScore, int noOfStudents) {
super();
this.name = name;
this.category = category;
this.reviewScore = reviewScore;
this.noOfStudents = noOfStudents;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getCategory() {
return category;
}
public void setCategory(String category) {
this.category = category;
}
public int getReviewScore() {
return reviewScore;
}
public void setReviewScore(int reviewScore) {
this.reviewScore = reviewScore;
}
public int getNoFoStudents() {
return noOfStudents;
}
public void setNoOfStudents(int noFoStudents) {
this.noOfStudents = noFoStudents;
}
@Override
public String toString() {
return "Course [name=" + name + ", category=" + category + ", reviewScore=" + reviewScore + ", noFoStudents="
+ noOfStudents + "]";
}
}
public class FP04CustomClass {
private static void println(String str) {
System.out.println(str);
}
public static void main(String[] args) {
List<Course> courses = Arrays.asList(
new Course("Spring", "Freamework",99,25500),
new Course("Spring Boot", "Freamework",67,26600),
new Course("API", "Microservice",98,27700),
new Course("Shin", "Name",78,20000),
new Course("Kim", "Name",89,20990),
new Course("RectJs", "Freamework",91,20000),
new Course("Angular", "Freamework",75,20550),
new Course("MariaDB", "Database",100,20044),
new Course("MsSQL", "Database",94,20088),
new Course("Oracle", "Database",83,23000),
new Course("Lambda", "AWS",100,20033),
new Course("EC2", "AWS",91,21220),
new Course("CDk", "AWS",90,20110)
);
Comparator<Course> comparatingByNoOfStudentsIncreasing = Comparator.comparing(Course::getNoFoStudents);
System.out.println(
courses.stream().sorted(comparatingByNoOfStudentsIncreasing).collect(Collectors.toList())
);
Comparator<Course> comparatingByNoOfStudentsDecreasing = Comparator.comparing(Course::getNoFoStudents).reversed();
System.out.println(
courses.stream().sorted(comparatingByNoOfStudentsDecreasing).collect(Collectors.toList())
);
Comparator<Course> comparatingByNoOfStudentsAndNoOfReviews = Comparator.comparing(Course::getNoFoStudents).thenComparing(Course::getReviewScore).reversed();
System.out.println(
courses.stream().sorted(comparatingByNoOfStudentsAndNoOfReviews).collect(Collectors.toList())
);
// comparingInt thenComparingInt...
Comparator<Course> comparatingByNoOfStudentsAndNoOfReviews_2 = Comparator.comparingInt(Course::getNoFoStudents).thenComparingInt(Course::getReviewScore).reversed();
System.out.println(
courses.stream().sorted(comparatingByNoOfStudentsAndNoOfReviews).collect(Collectors.toList())
);
}
}

Java Stream -Step 05 Comparator

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