The best practice and recommendation of the UNDERSCORE framework in the Java library
The best practice and recommendation of using the UNDERSCORE framework in the Java library
Introduction: Underscore is a functional and flexible Java class library for processing data structures such as sets, arrays, objects and functions.It provides a set of powerful functional programming tools that can simplify code writing and improve the readability and maintenance of the code.This article will share the best practice and recommendation of using the Underscore framework in the Java library.
1. Introduce the UNDERSCORE framework
Using the Underscore framework in the project, you need to add it to the dependencies first.You can introduce the latest version of the Underscore framework through Maven or Gradle.The following is a maven example configuration:
<dependency>
<groupId>com.github.javadev</groupId>
<artifactId>underscore-java</artifactId>
<version>1.50</version>
</dependency>
2. Treatment of collection and array
UNDERSCORE provides a rich collection and array processing function, which can easily perform operations such as filtering, mapping, and aggregation.Here are some common operation examples that use UNDERSCORE processing collection:
import com.github.underscore.Predicate;
import static com.github.underscore.Underscore.*;
public class CollectionExample {
public static void main(String[] args) {
// Create a string list
List<String> names = Arrays.asList("Alice", "Bob", "Charlie", "David");
// Filter the string with a length of 4
List<String> result = _.filter(names, (Predicate<String>)str -> str.length() == 4);
System.out.println (result); // Output: [Alice, Charlie, David]
// All string in the conversion list are uppercase
List<String> uppercase = _.map(names, String::toUpperCase);
System.out.println(uppercase); // 输出: [ALICE, BOB, CHARLIE, DAVID]
// Get the first element in the list
String first = _.first(names);
System.out.println (fIRST); // Output: Alice
// Judging whether the list contains specific elements
boolean contains = _.contains(names, "Charlie");
System.out.println (contains); // Output: true
// Calculate the sum of the length of the string in the calculation list
int sum = _.reduce(names, (memo, str) -> memo + str.length(), 0);
System.out.println (SUM); // Output: 19
}
}
3. Object treatment
UNDERSCORE can help us handle objects more conveniently, such as extracting a certain attribute from the object list, sorting according to the attributes, etc.The following is an example of using the UNDERSCORE operation object:
import com.github.underscore.Function1;
import static com.github.underscore.Underscore.*;
class Person {
private String name;
private int age;
public Person(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public int getAge() {
return age;
}
@Override
public String toString() {
return "Person{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
}
public class ObjectExample {
public static void main(String[] args) {
// Create a list of Person objects
List<Person> persons = Arrays.asList(
new Person("Alice", 25),
new Person("Bob", 30),
new Person("Charlie", 20)
);
// Extract the name of all Person objects
List<String> names = _.pluck(persons, "name");
System.out.println (names); // Output: [Alice, Bob, Charlie]
// Sort the Person object according to age
List<Person> sortedPersons = _.sortBy(persons, person -> person.getAge());
System.out.println(sortedPersons); // 输出: [Person{name='Charlie', age=20}, Person{name='Alice', age=25}, Person{name='Bob', age=30}]
// Get the first Person object that matches according to the specified conditions
Person matchPerson = _.find(persons, person -> person.getAge() > 25);
System.out.println (matchperson); // Output: Person {name = 'bob', age = 30}
// Determine whether the list of objects meets all the specified conditions
boolean allMatch = _.all(persons, person -> person.getAge() > 18);
System.out.println (allMatch); // Output: true
}
}
Conclusion: By introducing the UNDERSCORE framework and using the above best practice and recommendation, it can effectively simplify the processing of data structures such as collection, array and objects in the Java class library, and improve the readability and maintenance of the code.By using the rich functions provided by Underscore reasonably, we can write the Java code more efficiently.
I hope this article will help you use the best practice and recommendation of using the Underscore framework in the Java library!
