[Java Spring Data] Query method clauses and expressions

Entity:

package com.example.university.domain;

import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;

/**
 * JPA Entity representing a student at the University.
 *
 * Created by maryellenbowman
 */
@Entity
@Table(name="STUDENT")
public class Student {
    @Id
    @GeneratedValue
    private Integer studentId;

    @Embedded
    private Person attendee;

    @Column
    private boolean fullTime;

    @Column
    private Integer age;

    @OneToMany(fetch = FetchType.EAGER,
            cascade = CascadeType.ALL)
    private List<Course> courses = new ArrayList<>();

    public Student(Person attendee, boolean fullTime, Integer age) {
        this.attendee = attendee;
        this.fullTime = fullTime;
        this.age = age;
        courses = new ArrayList<>();
    }

    protected Student() {
    }

    public Integer getStudentId() {
        return studentId;
    }

    public Person getAttendee() {
        return attendee;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public boolean isFullTime() {
        return fullTime;
    }

    public Integer getAge() {
        return age;
    }

    public List<Course> getCourses() {
        return courses;
    }

    @Override
    public String toString() {
        return "Student{" + "studentId=" + studentId + ", " + attendee +  ", fullTime=" + fullTime +
                ", age=" + age + "}\n";
    }
}

　　

package com.example.university.domain;

import javax.persistence.Column;
import javax.persistence.Embeddable;

/**
 * Person encapsulates an individual's first and last name.
 *
 * Created by maryellenbowman
 */
@Embeddable
public class Person {
    @Column
    private String firstName;

    @Column
    private String lastName;

    public Person(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    protected Person() {
    }

    public String getFirstName() {
        return firstName;
    }

    public String getLastName() {
        return lastName;
    }

    @Override
    public String toString() {
        return  " firstName='" + firstName + '\'' +
                ", lastName='" + lastName + "\' ";
    }
}

　　

package com.example.university.domain;

import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;

/**
 * JPA Entity for a Course offered at the University.
 *
 * Created by maryellenbowman.
 */
@Entity
@Table(name="COURSE")
public class Course {
    @Id
    @GeneratedValue
    private Integer id;

    @Column
    private String name;

    @Column
    private Integer credits;

    @OneToOne
    private Staff instructor;

    @ManyToMany(fetch = FetchType.EAGER,
            cascade = CascadeType.ALL)
    private List<Course> prerequisites = new ArrayList<>();


    @ManyToOne
    private Department department;

    public Course(String name, Integer credits, Staff instructor, Department department) {
        this.name = name;
        this.credits = credits;
        this.instructor = instructor;
        this.department = department;
    }

    protected Course() {
    }

    public Integer getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public Staff getInstructor() {
        return instructor;
    }

    public Department getDepartment() {
        return department;
    }

    public Course addPrerequisite(Course prerequisite){
        prerequisites.add(prerequisite);
        return this;
    }


    @Override
    public String toString() {
        return "Course{" +
                "name='" + name + '\'' +
                ", id=" + id +
                ", credits=" + credits +
                ", instructor=" + instructor +
                ", department=" + department.getName() +
                '}';
    }
}

　　

package com.example.university.repo;

import com.example.university.domain.Person;
import com.example.university.domain.Student;
import org.springframework.data.repository.CrudRepository;

import java.util.List;

/**
 * DataSource Management for the Students at the University.
 *
 * Created by maryellenbowman
 */
public interface StudentRepository extends CrudRepository<Student, Integer>{
    //Simple Query Methods
    List<Student> findByFullTime(boolean fullTime);
    List<Student> findByAge(Integer age);
    List<Student> findByAttendeeLastName(String last);

    //Query Methods with Clauses and Exrpessions
    Student findByAttendeeFirstNameAndAttendeeLastName(String firstName, String lastName);
    Student findByAttendee(Person person);
    List<Student> findByAgeGreaterThan(int minimumAge);
    List<Student> findByAgeLessThan(int maximumAge);
    List<Student> findByAttendeeLastNameIgnoreCase(String lastName);
    // studentRepository.findByAttendeeLastNameLike("%i%").forEach(System.out::println);
    List<Student> findByAttendeeLastNameLike(String likeString);
    // Find highest student in the alphabet
    Student findFirstByOrderByAttendeeLastNameAsc();
    // Find the oldest student
    Student findTopByOrderByAgeDesc();
    // Find 3 oldest students
    List<Student> findTop3ByOrderByAgeDesc();
}

　　

Supported query keywords