How to use the UNDERSCORE framework in the Java library for data processing
Use the UNDERSCORE framework in the Java library for data processing
introduction:
Java is a functional and widely used programming language. It provides many powerful libraries and frameworks for handling various tasks.In terms of data processing, especially the operation of collecting data, Java provides some basic methods, but there are still some tedious operations that need to be implemented by developers.To simplify these operations, the Underscore framework came into being.This article will introduce how to use the Underscore framework in the Java library for data processing and provide the corresponding Java code example.
What is the UNDERSCORE framework:
Underscore is a library that provides smooth, functional programming styles for Java, which provides some convenient methods to process collection data.Its design is inspired by functional programming language, such as the Underscore.js framework in Scala and JavaScript.Using the Underscore framework, it can be easier to screen, conversion, and grouping, and perform common tasks for functional programming.
How to integrate the UNDERSCORE framework:
First, we need to integrate the Underscore framework into our Java project.You can introduce Underscore's dependencies through building tools such as Maven or Gradle.The following is an example configuration using Maven:
<dependency>
<groupId>com.github.javadev</groupId>
<artifactId>underscore</artifactId>
<version>1.45</version>
</dependency>
After introducing dependencies, we can use the Underscore framework function in the Java class.
Example of the UNDERSCORE framework:
Here are some common UNDERSCORE framework examples:
1. Filter:
By using the UNDERSCORE framework, we can more easily screen out the qualified elements in the collection.For example, if we have a list containing an integer, we can use the Filter method of the UNDERSCORE framework to screen the elements greater than 10:
import com.github.underscore.lodash.U;
import java.util.Arrays;
import java.util.List;
public class UnderscoreExample {
public static void main(String[] args) {
List<Integer> numbers = Arrays.asList(5, 15, 8, 20, 10);
List<Integer> filteredNumbers = U.filter(numbers, number -> number > 10);
System.out.println (Filterednumbers); // Output: [15, 20]
}
}
2. Conversion:
The UNDERSCORE framework also provides some convenient methods that allow us to convert elements in the collection more easily.For example, we can use the MAP method to convert the elements in the string list into uppercase:
import com.github.underscore.lodash.U;
import java.util.Arrays;
import java.util.List;
public class UnderscoreExample {
public static void main(String[] args) {
List<String> strings = Arrays.asList("java", "underscore", "framework");
List<String> uppercaseStrings = U.map(strings, String::toUpperCase);
System.out.println(uppercaseStrings); // 输出：[JAVA, UNDERSCORE, FRAMEWORK]
}
}
3. Grouping:
By using the Groupby method, we can group elements in the collection according to the specified conditions.For example, we can group a group of people according to gender:
import com.github.underscore.lodash.U;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
public class UnderscoreExample {
public static void main(String[] args) {
List<Person> people = Arrays.asList(
new Person("Alice", "female"),
new Person("Bob", "male"),
new Person("Carol", "female"),
new Person("Dave", "male")
);
Map<String, List<Person>> groupedPeople = U.groupBy(people, Person::getGender);
System.out.println(groupedPeople);
// Output:
// {
// female=[Person{name='Alice', gender='female'}, Person{name='Carol', gender='female'}],
// male=[Person{name='Bob', gender='male'}, Person{name='Dave', gender='male'}]
// }
}
}
class Person {
private String name;
private String gender;
// omit the constructor and getter/setter method
}
The above is just a small part of functional examples provided by the Underscore framework. In fact, it also provides many other useful methods, such as Reduce, Every, SOME and so on.
in conclusion:
Using the Underscore framework can greatly simplify the data processing operation in the Java class library.It provides some simple and smooth methods to process collection data, making the code easier to read and maintain.By introducing the dependencies of the UNDERSCORE framework and using the method provided by the framework, we can complete the data processing task more efficiently.
Reference link:
1. Underscore official github warehouse: https://github.com/javadev/underscore
