java - 为什么 GSON 无法从 JSON 文件中检索所有值？

Question

我正在编写一个程序，尝试使用 GSON 从 JSON 文件检索值，但是，我注意到 GSON 无法检索我的所有值。例如，在 eclipse 中进入 Debug模式，我发现大多数值都是 null。

Debug模式: Picture When Accessing Variables In Debug Mode In Eclipse

这是我的 JSON 文件:

{
"shoes": [
    {
        "shoeName": "Shoe",
        "shoePrice": "120",
        "brand": "Shoe",
        "typeOfShoes": "Running",
        "style": "Cool",
        "Color": [
            "Blue",
            "Green",
            "Pink"
        ],
        "Sizes": [
            "W5/M3.5",
            "W5.5/M4"
        ],
        "Description": "The Shoe SE features sleek lines and a sheer upper that combine classic Air Max elements into a lightweight, comfortable and versatile icon. Together with its smart toe-down profile and extra lift, the shoe offers an ever-bigger expression..",
        "shipping": "0",
        "tax": "0",
        "sub-total": "0",
        "review": "4.5",
        "totalRaffles": "80",
        "isSold": "false"
    },
    {
        "shoeName": "Empty Shoe",
        "shoePrice": "0",
        "brand": "null",
        "typeOfShoes": "null",
        "style": "null",
        "Color": ["null"
        ],
        "Sizes": ["null"
        ],
        "Description": "null",
        "shipping": "0",
        "tax": "0",
        "sub-total": "0",
        "review": "0",
        "totalRaffles": "0",
        "isSold": "false"
    },
    {
        "shoeName": "Empty Shoe1",
        "shoePrice": "0",
        "brand": "null",
        "typeOfShoes": "null",
        "style": "null",
        "Color": ["null"
        ],
        "Sizes": ["null"
        ],
        "Description": "null",
        "shipping": "0",
        "tax": "0",
        "sub-total": "0",
        "review": "0",
        "totalRaffles": "0",
        "isSold": "false"
    }
]

}

JSON 文件的结构相对简单。有多个对象(鞋子)，每个对象都有自己的属性，例如 ShoesName、shoePrice 等。

ReadJSON.java

import java.io.File;
import java.io.IOException;
import java.lang.reflect.Type;
import java.nio.file.Files;
import java.util.List;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import com.pulsebeat02.main.gui.Shoe;
import com.pulsebeat02.main.gui.windows.StartingWindow;

public class ReadJSON {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        parseJSON();

    }

    public static void parseJSON() {

        String cwd = System.getProperty("user.dir");

        File f = new File(cwd + "/shoes.json");

        String str = null;
        try {
            str = readFile(f);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        Gson gson = new Gson();

        Type dataType = (new TypeToken<Shoes>() {
        }).getType();

        Shoes shoeList = gson.fromJson(str, dataType);

        List<Shoe> shoes = shoeList.getShoes();

        Shoe[] shoesFinal = new Shoe[shoes.size()];

        for (int i = 0; i < shoesFinal.length; i++) {

            shoesFinal[i] = shoes.get(i);

        }

        StartingWindow.shoesInGui = shoesFinal;

        System.out.println(shoeList);
        System.out.println("Ran");

    }

    public static String readFile(File file) throws IOException {
        return new String(Files.readAllBytes(file.toPath()));
    }

}

因为 JSON 文件中有多个对象(鞋子)，所以我必须创建一个名为“Shoes.java”的类来创建鞋子列表。

Shoes.java

import java.util.List;

import com.pulsebeat02.main.gui.Shoe;

public class Shoes {

    private List<Shoe> shoes;

    public List<Shoe> getShoes() {
        return shoes;
    }

    public void setShoes(List<Shoe> shoes) {
        this.shoes = shoes;
    }

}

最后，这是我的 Shoe.java 类，它定义了 Shoe 对象。

Shoe.java

import java.awt.Image;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.List;

import javax.imageio.ImageIO;

public class Shoe {

    public int shoePrice;
    public int shipping;
    public int tax;
    public int subtotal;
    public int totalUsers;

    public double review;

    public int totalRaffles;

    public String shoeName;
    public String style;
    public String typeOfShoes;
    public String brand;

    public Image[] images;

    public String name;
    public String description;
    public String[] colors;
    public String[] sizes;

    public boolean isSold;

    public Shoe(int shoePrice, int shipping, int tax, int subtotal, double review,

            int totalRaffles,

            String shoeName, String style, String typeOfShoes, String brand,

            Image[] images,

            String description, String[] colors, String[] sizes,

            boolean isSold) {

        this.shoePrice = shoePrice;
        this.shipping = shipping;
        this.tax = tax;
        this.subtotal = subtotal;
        this.review = review;
        this.totalRaffles = totalRaffles;
        this.sizes = sizes;
        this.shoeName = shoeName;
        this.style = style;
        this.typeOfShoes = typeOfShoes;
        this.images = images;
        this.description = description;
        this.colors = colors;
        this.isSold = isSold;
        this.brand = brand;

    }

    public Shoe(String shoePrice2, String shipping2, String tax2, String subTotal2, String review2,
            String totalRaffles2, String shoeName2, String style2, String typeOfShoes2, String brand2,
            List<String> images2, String description2, List<String> color, List<String> sizes2, String isSold2) {

        this.shoePrice = Integer.parseInt(shoePrice2);
        this.shipping = Integer.parseInt(shipping2);
        this.tax = Integer.parseInt(tax2);
        this.subtotal = Integer.parseInt(subTotal2);
        this.review = Double.parseDouble(review2);
        this.totalRaffles = Integer.parseInt(totalRaffles2);

        this.shoeName = shoeName2;
        this.style = style2;
        this.typeOfShoes = typeOfShoes2;
        this.brand = brand2;

        this.images = loadImage((String[]) images2.toArray());
        this.description = description2;
        this.colors = (String[]) color.toArray();
        this.sizes = (String[]) sizes2.toArray();
        this.isSold = Boolean.getBoolean(isSold2);

    }

    public static Shoe[] toArray(List<Shoe> list) {

        Shoe[] shoes = new Shoe[list.size()];

        for (int i = 0; i < list.size(); i++) {

            shoes[i] = list.get(i);

        }

        return shoes;

    }

    public static Image[] loadImage(String[] imageURLs) {

        Image[] images = new Image[imageURLs.length];

        for (int i = 0; i < imageURLs.length; i++) {

            Image image = null;
            try {
                image = ImageIO.read(new URL(imageURLs[i]));
            } catch (MalformedURLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            images[i] = image;

        }

        return images;

    }

有谁知道 GSON 在这里使 SHoe 对象的属性为空的问题吗？

Answer 1

我找到了这个问题的解决方案。对于使用 GSON 作为 JSON 解析器的人，请确保检查变量名称并确保它们与 JSON 文件中的变量名称匹配，否则它们将为空。谢谢samabcde!