网络pojo类和数据库实体类,如何避免重复

Question

对不起,如果怀疑太概念化,我有点缺乏经验......

我通过改造从URL获取JSON数据,我还想将这些数据存储在我的SQLite数据库中.要创建此数据库,我将使用新的Room ORM映射.

我使用Android Studio插件GsonFormat提取网络POJO类,并在下面生成食谱,成分和步骤类.并生成一些Room Entity类(更多下面)

如您所见,两组类几乎相同,带来了大量重复的代码.但我也觉得混合使用这两组课程并不好.并且Room禁止实体对象互相引用,所以如果我想使用第一组类,它会更复杂......

我怀疑这些案件一般是如何处理的？

--- Pojo - Gson可以理解:

public class Recipes {

    private int id;
    private String name;
    private int servings;
    private String image;
    private List<Ingredients> ingredients;
    private List<Steps> steps;

    public int getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public int getServings() {
        return servings;
    }

    public void setServings(int servings) {
        this.servings = servings;
    }

    public String getImage() {
        return image;
    }

    public void setImage(String image) {
        this.image = image;
    }

    public List<Ingredients> getIngredients() {
        return ingredients;
    }

    public void setIngredients(List<Ingredients> ingredients) {
        this.ingredients = ingredients;
    }

    public List<Steps> getSteps() {
        return steps;
    }

    public void setSteps(List<Steps> steps) {
        this.steps = steps;
    }

    @Override
    public String toString() {
        return "Recipes{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", servings=" + servings +
                ", image='" + image + '\'' +
                ", ingredients=" + ingredients +
                ", steps=" + steps +
                '}';
    }
}

class Ingredients {
    private double quantity;
    private String measure;
    private String ingredient;

    public double getQuantity() {
        return quantity;
    }

    public void setQuantity(double quantity) {
        this.quantity = quantity;
    }

    public String getMeasure() {
        return measure;
    }

    public void setMeasure(String measure) {
        this.measure = measure;
    }

    public String getIngredient() {
        return ingredient;
    }

    public void setIngredient(String ingredient) {
        this.ingredient = ingredient;
    }

    @Override
    public String toString() {
        return "Ingredients{" +
                "quantity=" + quantity +
                ", measure='" + measure + '\'' +
                ", ingredient='" + ingredient + '\'' +
                '}';
    }
}

class Steps {

    private int id;
    private String shortDescription;
    private String description;
    private String videoURL;
    private String thumbnailURL;

    public int getId() {
        return id;
    }

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

    public String getShortDescription() {
        return shortDescription;
    }

    public void setShortDescription(String shortDescription) {
        this.shortDescription = shortDescription;
    }

    public String getDescription() {
        return description;
    }

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

    public String getVideoURL() {
        return videoURL;
    }

    public void setVideoURL(String videoURL) {
        this.videoURL = videoURL;
    }

    public String getThumbnailURL() {
        return thumbnailURL;
    }

    public void setThumbnailURL(String thumbnailURL) {
        this.thumbnailURL = thumbnailURL;
    }

    @Override
    public String toString() {
        return "Steps{" +
                "id=" + id +
                ", shortDescription='" + shortDescription + '\'' +
                ", description='" + description + '\'' +
                ", videoURL='" + videoURL + '\'' +
                ", thumbnailURL='" + thumbnailURL + '\'' +
                '}';
    }
}

---房间实体班

@Entity
public class Recipe {

    @PrimaryKey
    private int id;

    private String name;
    private int servings;
    private String image;

}


@Entity(foreignKeys = @ForeignKey(entity = Recipe.class,
        parentColumns = "id",
        childColumns = "recipeId"))
public class Ingredient {

    @PrimaryKey
    private int id;
    private double quantity;
    private String measure;
    private String ingredient;


    private int recipeId;

}

Answer 1

您可以使用一个同时满足 Gson 和 Room 映射的 Object 类。

例如。

@Entity
public class Recipe {
  @PrimaryKey           // Room annotation
  @SerializedName("id") // Gson annotation
  private int id;

  @ColumnInfo(name = "name") // Room annotation
  @SerializedName("name")    // Gson annotation
  private String name;
  ....
}

在编译过程中，Gson 和 Room 会寻找注解来映射正确的实体。
一般来说，它们只是普通的 POJO 对象，带有特定的注释，以帮助其他框架正确使用它。