使用GSON使用元素数组解析JSON对象

Question

如何使用GSON解析以下JSON对象：

{
    "ProductsByCategory": [
     {.....},
     {.....},
     {.....},
     {.....},
]
}

JSON对象包含一系列元素。我正在使用GSON来尝试解析JSON并使用以下POJO类来帮助我。

public class ProductItems {

    @SerializedName("ProductsByCategory")
    @Expose
    private List<ProductsByCategory> productsByCategory = null;

    public List<ProductsByCategory> getProductsByCategory() {
        return productsByCategory;
    }

    public void setProductsByCategory(List<ProductsByCategory> productsByCategory) {
        this.productsByCategory = productsByCategory;
    }

}

public class ProductsByCategory {

    @SerializedName("id")
    @Expose
    private Integer id;
    @SerializedName("name")
    @Expose
    private String name;
    @SerializedName("slug")
    @Expose
    private String slug;
    @SerializedName("permalink")
    @Expose
    private String permalink;
    @SerializedName("date_created")
    @Expose
    private String dateCreated;
    @SerializedName("date_created_gmt")
    @Expose
    private String dateCreatedGmt;
    @SerializedName("date_modified")
    @Expose
    private String dateModified;
    @SerializedName("date_modified_gmt")
    @Expose
    private String dateModifiedGmt;
    @SerializedName("type")
    @Expose
    private String type;
    @SerializedName("status")
    @Expose
    private String status;
    @SerializedName("featured")
    @Expose
    private Boolean featured;
    @SerializedName("catalog_visibility")
    @Expose
    private String catalogVisibility;
    @SerializedName("description")
    @Expose
    private String description;
    @SerializedName("short_description")
    @Expose
    private String shortDescription;
    @SerializedName("sku")
    @Expose
    private String sku;
    @SerializedName("price")
    @Expose
    private String price;
    @SerializedName("regular_price")
    @Expose
    private String regularPrice;
    @SerializedName("sale_price")
    @Expose
    private String salePrice;
    @SerializedName("date_on_sale_from")
    @Expose
    private Object dateOnSaleFrom;
    @SerializedName("date_on_sale_from_gmt")
    @Expose
    private Object dateOnSaleFromGmt;
    @SerializedName("date_on_sale_to")
    @Expose
    private Object dateOnSaleTo;
    @SerializedName("date_on_sale_to_gmt")
    @Expose
    private Object dateOnSaleToGmt;
    @SerializedName("price_html")
    @Expose
    private String priceHtml;
    @SerializedName("on_sale")
    @Expose
    private Boolean onSale;
    @SerializedName("purchasable")
    @Expose
    private Boolean purchasable;
    @SerializedName("total_sales")
    @Expose
    private Integer totalSales;
    @SerializedName("virtual")
    @Expose
    private Boolean virtual;
    @SerializedName("downloadable")
    @Expose
    private Boolean downloadable;
    @SerializedName("downloads")
    @Expose
    private List<Object> downloads = null;
    @SerializedName("download_limit")
    @Expose
    private Integer downloadLimit;
    @SerializedName("download_expiry")
    @Expose
    private Integer downloadExpiry;
    @SerializedName("external_url")
    @Expose
    private String externalUrl;
    @SerializedName("button_text")
    @Expose
    private String buttonText;
    @SerializedName("tax_status")
    @Expose
    private String taxStatus;
    @SerializedName("tax_class")
    @Expose
    private String taxClass;
    @SerializedName("manage_stock")
    @Expose
    private Boolean manageStock;
    @SerializedName("stock_quantity")
    @Expose
    private Integer stockQuantity;
    @SerializedName("in_stock")
    @Expose
    private Boolean inStock;
    @SerializedName("backorders")
    @Expose
    private String backorders;
    @SerializedName("backorders_allowed")
    @Expose
    private Boolean backordersAllowed;
    @SerializedName("backordered")
    @Expose
    private Boolean backordered;
    @SerializedName("sold_individually")
    @Expose
    private Boolean soldIndividually;
    @SerializedName("weight")
    @Expose
    private String weight;
    @SerializedName("dimensions")
    @Expose
    private Dimensions dimensions;
    @SerializedName("shipping_required")
    @Expose
    private Boolean shippingRequired;
    @SerializedName("shipping_taxable")
    @Expose
    private Boolean shippingTaxable;
    @SerializedName("shipping_class")
    @Expose
    private String shippingClass;
    @SerializedName("shipping_class_id")
    @Expose
    private Integer shippingClassId;
    @SerializedName("reviews_allowed")
    @Expose
    private Boolean reviewsAllowed;
    @SerializedName("average_rating")
    @Expose
    private String averageRating;
    @SerializedName("rating_count")
    @Expose
    private Integer ratingCount;
    @SerializedName("related_ids")
    @Expose
    private List<Integer> relatedIds = null;
    @SerializedName("upsell_ids")
    @Expose
    private List<Object> upsellIds = null;
    @SerializedName("cross_sell_ids")
    @Expose
    private List<Object> crossSellIds = null;
    @SerializedName("parent_id")
    @Expose
    private Integer parentId;
    @SerializedName("purchase_note")
    @Expose
    private String purchaseNote;
    @SerializedName("categories")
    @Expose
    private List<Category> categories = null;
    @SerializedName("tags")
    @Expose
    private List<Object> tags = null;
    @SerializedName("images")
    @Expose
    private List<Image> images = null;
    @SerializedName("attributes")
    @Expose
    private List<Attribute> attributes = null;
    @SerializedName("default_attributes")
    @Expose
    private List<Object> defaultAttributes = null;
    @SerializedName("variations")
    @Expose
    private List<Integer> variations = null;
    @SerializedName("grouped_products")
    @Expose
    private List<Object> groupedProducts = null;
    @SerializedName("menu_order")
    @Expose
    private Integer menuOrder;
    @SerializedName("meta_data")
    @Expose
    private List<MetaDatum> metaData = null;
    @SerializedName("_links")
    @Expose
    private Links links;

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public String getSlug() {
        return slug;
    }

    public void setSlug(String slug) {
        this.slug = slug;
    }

    public String getPermalink() {
        return permalink;
    }

    public void setPermalink(String permalink) {
        this.permalink = permalink;
    }

    public String getDateCreated() {
        return dateCreated;
    }

    public void setDateCreated(String dateCreated) {
        this.dateCreated = dateCreated;
    }

    public String getDateCreatedGmt() {
        return dateCreatedGmt;
    }

    public void setDateCreatedGmt(String dateCreatedGmt) {
        this.dateCreatedGmt = dateCreatedGmt;
    }

    public String getDateModified() {
        return dateModified;
    }

    public void setDateModified(String dateModified) {
        this.dateModified = dateModified;
    }

    public String getDateModifiedGmt() {
        return dateModifiedGmt;
    }

    public void setDateModifiedGmt(String dateModifiedGmt) {
        this.dateModifiedGmt = dateModifiedGmt;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }

    public Boolean getFeatured() {
        return featured;
    }

    public void setFeatured(Boolean featured) {
        this.featured = featured;
    }

    public String getCatalogVisibility() {
        return catalogVisibility;
    }

    public void setCatalogVisibility(String catalogVisibility) {
        this.catalogVisibility = catalogVisibility;
    }

    public String getDescription() {
        return description;
    }

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

    public String getShortDescription() {
        return shortDescription;
    }

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

    public String getSku() {
        return sku;
    }

    public void setSku(String sku) {
        this.sku = sku;
    }

    public String getPrice() {
        return price;
    }

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

    public String getRegularPrice() {
        return regularPrice;
    }

    public void setRegularPrice(String regularPrice) {
        this.regularPrice = regularPrice;
    }

    public String getSalePrice() {
        return salePrice;
    }

    public void setSalePrice(String salePrice) {
        this.salePrice = salePrice;
    }

    public Object getDateOnSaleFrom() {
        return dateOnSaleFrom;
    }

    public void setDateOnSaleFrom(Object dateOnSaleFrom) {
        this.dateOnSaleFrom = dateOnSaleFrom;
    }

    public Object getDateOnSaleFromGmt() {
        return dateOnSaleFromGmt;
    }

    public void setDateOnSaleFromGmt(Object dateOnSaleFromGmt) {
        this.dateOnSaleFromGmt = dateOnSaleFromGmt;
    }

    public Object getDateOnSaleTo() {
        return dateOnSaleTo;
    }

    public void setDateOnSaleTo(Object dateOnSaleTo) {
        this.dateOnSaleTo = dateOnSaleTo;
    }

    public Object getDateOnSaleToGmt() {
        return dateOnSaleToGmt;
    }

    public void setDateOnSaleToGmt(Object dateOnSaleToGmt) {
        this.dateOnSaleToGmt = dateOnSaleToGmt;
    }

    public String getPriceHtml() {
        return priceHtml;
    }

    public void setPriceHtml(String priceHtml) {
        this.priceHtml = priceHtml;
    }

    public Boolean getOnSale() {
        return onSale;
    }

    public void setOnSale(Boolean onSale) {
        this.onSale = onSale;
    }

    public Boolean getPurchasable() {
        return purchasable;
    }

    public void setPurchasable(Boolean purchasable) {
        this.purchasable = purchasable;
    }

    public Integer getTotalSales() {
        return totalSales;
    }

    public void setTotalSales(Integer totalSales) {
        this.totalSales = totalSales;
    }

    public Boolean getVirtual() {
        return virtual;
    }

    public void setVirtual(Boolean virtual) {
        this.virtual = virtual;
    }

    public Boolean getDownloadable() {
        return downloadable;
    }

    public void setDownloadable(Boolean downloadable) {
        this.downloadable = downloadable;
    }

    public List<Object> getDownloads() {
        return downloads;
    }

    public void setDownloads(List<Object> downloads) {
        this.downloads = downloads;
    }

    public Integer getDownloadLimit() {
        return downloadLimit;
    }

    public void setDownloadLimit(Integer downloadLimit) {
        this.downloadLimit = downloadLimit;
    }

    public Integer getDownloadExpiry() {
        return downloadExpiry;
    }

    public void setDownloadExpiry(Integer downloadExpiry) {
        this.downloadExpiry = downloadExpiry;
    }

    public String getExternalUrl() {
        return externalUrl;
    }

    public void setExternalUrl(String externalUrl) {
        this.externalUrl = externalUrl;
    }

    public String getButtonText() {
        return buttonText;
    }

    public void setButtonText(String buttonText) {
        this.buttonText = buttonText;
    }

    public String getTaxStatus() {
        return taxStatus;
    }

    public void setTaxStatus(String taxStatus) {
        this.taxStatus = taxStatus;
    }

    public String getTaxClass() {
        return taxClass;
    }

    public void setTaxClass(String taxClass) {
        this.taxClass = taxClass;
    }

    public Boolean getManageStock() {
        return manageStock;
    }

    public void setManageStock(Boolean manageStock) {
        this.manageStock = manageStock;
    }

    public Integer getStockQuantity() {
        return stockQuantity;
    }

    public void setStockQuantity(Integer stockQuantity) {
        this.stockQuantity = stockQuantity;
    }

    public Boolean getInStock() {
        return inStock;
    }

    public void setInStock(Boolean inStock) {
        this.inStock = inStock;
    }

    public String getBackorders() {
        return backorders;
    }

    public void setBackorders(String backorders) {
        this.backorders = backorders;
    }

    public Boolean getBackordersAllowed() {
        return backordersAllowed;
    }

    public void setBackordersAllowed(Boolean backordersAllowed) {
        this.backordersAllowed = backordersAllowed;
    }

    public Boolean getBackordered() {
        return backordered;
    }

    public void setBackordered(Boolean backordered) {
        this.backordered = backordered;
    }

    public Boolean getSoldIndividually() {
        return soldIndividually;
    }

    public void setSoldIndividually(Boolean soldIndividually) {
        this.soldIndividually = soldIndividually;
    }

    public String getWeight() {
        return weight;
    }

    public void setWeight(String weight) {
        this.weight = weight;
    }

    public Dimensions getDimensions() {
        return dimensions;
    }

    public void setDimensions(Dimensions dimensions) {
        this.dimensions = dimensions;
    }

    public Boolean getShippingRequired() {
        return shippingRequired;
    }

    public void setShippingRequired(Boolean shippingRequired) {
        this.shippingRequired = shippingRequired;
    }

    public Boolean getShippingTaxable() {
        return shippingTaxable;
    }

    public void setShippingTaxable(Boolean shippingTaxable) {
        this.shippingTaxable = shippingTaxable;
    }

    public String getShippingClass() {
        return shippingClass;
    }

    public void setShippingClass(String shippingClass) {
        this.shippingClass = shippingClass;
    }

    public Integer getShippingClassId() {
        return shippingClassId;
    }

    public void setShippingClassId(Integer shippingClassId) {
        this.shippingClassId = shippingClassId;
    }

    public Boolean getReviewsAllowed() {
        return reviewsAllowed;
    }

    public void setReviewsAllowed(Boolean reviewsAllowed) {
        this.reviewsAllowed = reviewsAllowed;
    }

    public String getAverageRating() {
        return averageRating;
    }

    public void setAverageRating(String averageRating) {
        this.averageRating = averageRating;
    }

    public Integer getRatingCount() {
        return ratingCount;
    }

    public void setRatingCount(Integer ratingCount) {
        this.ratingCount = ratingCount;
    }

    public List<Integer> getRelatedIds() {
        return relatedIds;
    }

    public void setRelatedIds(List<Integer> relatedIds) {
        this.relatedIds = relatedIds;
    }

    public List<Object> getUpsellIds() {
        return upsellIds;
    }

    public void setUpsellIds(List<Object> upsellIds) {
        this.upsellIds = upsellIds;
    }

    public List<Object> getCrossSellIds() {
        return crossSellIds;
    }

    public void setCrossSellIds(List<Object> crossSellIds) {
        this.crossSellIds = crossSellIds;
    }

    public Integer getParentId() {
        return parentId;
    }

    public void setParentId(Integer parentId) {
        this.parentId = parentId;
    }

    public String getPurchaseNote() {
        return purchaseNote;
    }

    public void setPurchaseNote(String purchaseNote) {
        this.purchaseNote = purchaseNote;
    }

    public List<Category> getCategories() {
        return categories;
    }

    public void setCategories(List<Category> categories) {
        this.categories = categories;
    }

    public List<Object> getTags() {
        return tags;
    }

    public void setTags(List<Object> tags) {
        this.tags = tags;
    }

    public List<Image> getImages() {
        return images;
    }

    public void setImages(List<Image> images) {
        this.images = images;
    }

    public List<Attribute> getAttributes() {
        return attributes;
    }

    public void setAttributes(List<Attribute> attributes) {
        this.attributes = attributes;
    }

    public List<Object> getDefaultAttributes() {
        return defaultAttributes;
    }

    public void setDefaultAttributes(List<Object> defaultAttributes) {
        this.defaultAttributes = defaultAttributes;
    }

    public List<Integer> getVariations() {
        return variations;
    }

    public void setVariations(List<Integer> variations) {
        this.variations = variations;
    }

    public List<Object> getGroupedProducts() {
        return groupedProducts;
    }

    public void setGroupedProducts(List<Object> groupedProducts) {
        this.groupedProducts = groupedProducts;
    }

    public Integer getMenuOrder() {
        return menuOrder;
    }

    public void setMenuOrder(Integer menuOrder) {
        this.menuOrder = menuOrder;
    }

    public List<MetaDatum> getMetaData() {
        return metaData;
    }

    public void setMetaData(List<MetaDatum> metaData) {
        this.metaData = metaData;
    }

    public Links getLinks() {
        return links;
    }

    public void setLinks(Links links) {
        this.links = links;
    }

}

我使用的代码如下：

   public void onResponse(Call call, Response response) throws IOException
        {

            String mMessage = response.body().string();
            if (response.isSuccessful())
            {
                try
                {
                    Gson gson = new Gson();
                    final ProductItems categoryProducts = gson.fromJson(mMessage, ProductItems.class);


                    response.close();
                }
                catch (Exception e)
                {
                    Log.e("Error", "Failed to upload");
                    e.printStackTrace();
                }

但是，我收到以下错误：GSON抛出“预期的BEGIN_OBJECT但是BEGIN_ARRAY。 我试图将ProductItems类更改为为productbycategories获取一个对象，但后来我收到以下错误：com.google.gson.JsonSyntaxException：java.lang.IllegalStateException：期望一个字符串，但在第1行第2324行路径$是BEGIN_OBJECT。 ProductsByCategory [0] .meta_data [0]。价值。我现在有点困惑。

Answer 1

您收到此错误的原因是数据与POJO的生成方式不一致。

这是存在问题的数据的具体部分：

＆＃34; meta_data＆＃34;：[                 {                     ＆＃34; id＆＃34;：14232，                     ＆＃34; key＆＃34;：＆＃34; _vc_post_settings＆＃34;，                     ＆＃34; value＆＃34;：{                         ＆＃34; vc_grid_id＆＃34;：[]                     }                 }，                 {                     ＆＃34; id＆＃34;：14273，                     ＆＃34; key＆＃34;：＆＃34; fb_product_description＆＃34;，                     ＆＃34;价值＆＃34;：＆＃34;＆＃34;                 }，                 {                     ＆＃34; id＆＃34;：14274，                     ＆＃34; key＆＃34;：＆＃34; fb_visibility＆＃34;，                     ＆＃34;价值＆＃34;：＆＃34; 1＆＃34;                 }，

注意＆＃34; meta_data＆＃34; field是一个对象数组，这些对象包含一个＆＃34;值＆＃34;领域。 ＆＃34;值的数据类型＆＃34;变化 - 有时它是一个对象，有时它是一个字符串。

一种可能的解决方案是更改MetaDatum课程，以便value为Object：

package com.example;

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class MetaDatum {

    ...

    @SerializedName("value")
    @Expose
    private Object value;

    ...

    public Object getValue() {
        return value;
    }

    public void setValue(Object value) {
        this.value = value;
    }

}