[Java Spring] JPA CrudRepository query language

Entity:

package com.example.ec.domain;

import javax.persistence.*;

@Entity
public class Tour {
    @Id
    @GeneratedValue
    private Integer id;

    @Column
    private String title;

    @Column(length = 2000)
    private String description;

    @Column(length = 2000)
    private String blurb;

    @Column
    private Integer price;

    @Column
    private String duration;

    @Column
    private String keywords;

    @Column(length = 2000)
    private String bullets;

    @ManyToOne
    private TourPackage tourPackage;

    @Column
    @Enumerated
    private Difficulty difficulty;

    @Column
    @Enumerated
    private Region region;

    public Tour(String title, String description, String blurb, Integer price, String duration, String bullets, String keywords, TourPackage tourPackage, Difficulty difficulty, Region region) {
        this.title = title;
        this.description = description;
        this.blurb = blurb;
        this.price = price;
        this.duration = duration;
        this.bullets = bullets;
        this.keywords = keywords;
        this.tourPackage = tourPackage;
        this.difficulty = difficulty;
        this.region = region;
    }

    protected Tour() {}

    public Integer getId() {
        return id;
    }

    public String getKeywords() {
        return keywords;
    }

    public void setKeywords(String keywords) {
        this.keywords = keywords;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public String getBlurb() {
        return blurb;
    }

    public void setBlurb(String blurb) {
        this.blurb = blurb;
    }

    public Integer getPrice() {
        return price;
    }

    public void setPrice(Integer price) {
        this.price = price;
    }

    public String getDuration() {
        return duration;
    }

    public void setDuration(String duration) {
        this.duration = duration;
    }

    public String getBullets() {
        return bullets;
    }

    public void setBullets(String bullets) {
        this.bullets = bullets;
    }

    public TourPackage getTourPackage() {
        return tourPackage;
    }

    public void setTourPackage(TourPackage tourPackage) {
        this.tourPackage = tourPackage;
    }

    public Difficulty getDifficulty() {
        return difficulty;
    }

    public void setDifficulty(Difficulty difficulty) {
        this.difficulty = difficulty;
    }

    public Region getRegion() {
        return region;
    }

    public void setRegion(Region region) {
        this.region = region;
    }
}

　　

package com.example.ec.domain;

import javax.persistence.Column;
import javax.persistence.Id;

public class TourPackage {
    @Id
    private String code;

    @Column
    private String name;

    protected TourPackage() {}

    public TourPackage(String code, String name) {
        this.code = code;
        this.name = name;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

In Repository, you can do baisc extension:

public interface TourPackageRepository extends CrudRepository<TourPackage, String> {
    Optional<TourPackage> findByName(String name);
}

You can combine multi Entities:

package com.example.ec.repo;

import com.example.ec.domain.Difficulty;
import com.example.ec.domain.Region;
import com.example.ec.domain.Tour;
import org.springframework.data.repository.CrudRepository;

import java.util.*;


public interface TourRepository extends CrudRepository<Tour, Integer> {
    List<Tour> findTourPackageCodeAndRegion(String code, Region region);

    List<Tour> findByRegionIn(List<Region> regions);

    List<Tour> findByPriceLessThan(Integer maxPrice);

    List<Tour> findByKeywordsContains(String keyword);

    List<Tour> findByTourPackageCodeAndBulletsLike(String code, String searchString);

    List<Tour> findByTourPackageCodeAndDifficultyAndRegionAndPriceLessThan(String code, Difficulty difficulty, Region region, Integer maxPrice);
}

But function name become pretty long and hard to understand, then we can switch to @Query:

package com.example.ec.repo;

import com.example.ec.domain.Difficulty;
import com.example.ec.domain.Region;
import com.example.ec.domain.Tour;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.CrudRepository;

import java.util.*;


public interface TourRepository extends CrudRepository<Tour, Integer> {

    @Query("Select t from Tour t where t.tourPackage.code = ?1" +
            " and t.difficult = ?2 and t.region = ?3 and t.price <= ?4")
    List<Tour> lookupTour(String code, Difficulty difficulty, Region region, Integer maxPrice);

    List<Tour> findByTourPackageCodeAndDifficultyAndRegionAndPriceLessThan(String code, Difficulty difficulty, Region region, Integer maxPrice);
}