Interpret the technical principles of the data framework in the Java library
The technical principles of the data framework in the Java class library
Data framework is a common programming mode in the Java language, which is used to encapsulate and manage data in the application application.It provides a structured and reusable way to process data by defining data classes and related operation methods.
Technical principle:
1. Data class definition: Data class is a class used to represent data, which contains a set of attributes to describe the characteristics of the data.In Java, a class and member variables can be used to define the data class.For example, a student's data class can contain attributes such as names, school numbers, and grades.
Example code:
public class Student {
private String name;
private int id;
private double score;
// Construction method
public Student(String name, int id, double score) {
this.name = name;
this.id = id;
this.score = score;
}
// getter and setter method
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public double getScore() {
return score;
}
public void setScore(double score) {
this.score = score;
}
}
2. Packaging and access control: The data class achieves packaging and access control by using private member variables and public access methods (Getter and Setter methods).Private member variables can only be accessed inside, and public access methods allow external code to access and modify data through these methods.
Example code:
Student Student = New Student ("Zhang San", 1234, 85.5);
System.out.println (Student.getName ()); // Output: "Zhang San"
student.setScore(90.0);
System.out.println (Student.getScore ()); // Output: 90.0
3. Data class feature processing: The data framework usually provides some convenient methods to process the characteristics of the data class, such as comparison, sorting, copying, and so on.These methods can help developers operate and manage data easier.
Example code:
List<Student> students = new ArrayList<>();
Students.add (New Student ("Zhang San", 1234, 85.5));
Students.add (New Student ("Li Si", 2345, 90.0));
Students.add (New Student ("Wang Wu", 3456, 70.5));
Collections.sort (Students, Comparator.comParing (Student :: GetScore)); // Sort it according to results
for (Student student : students) {
System.out.println(student.getName() + ": " + student.getScore());
}
// Output:
// Wang Wu: 70.5
// Zhang San: 85.5
// Li Si: 90.0
4. Scalability: The design of the data framework usually takes into account the scalability of the data, so that developers can define more complex data structures and behaviors by inheriting and expanding data classes.
Example code:
public class GraduateStudent extends Student {
private String advisor;
public GraduateStudent(String name, int id, double score, String advisor) {
super(name, id, score);
this.advisor = advisor;
}
public String getAdvisor() {
return advisor;
}
public void setAdvisor(String advisor) {
this.advisor = advisor;
}
}
GraduateStudent GraduatesStudent = New GraduatesStudent ("Wang Xiaohong", 4567, 88.5, "Teacher Li");
System.out.println (GraduateStudent.getName ()); // Output: "Wang Xiaohong"
System.out.println (graduatestudent.getAdvisor ()); // Output: "Teacher Li"
In summary, the data framework in the Java library provides a structured and reusable way to process data by packaging and managing data.Its technical principles include data definition, packaging and access control, data feature processing, and scalability.The use of these principles enables developers to operate and manage data in applications more conveniently.
