java - 为什么 GSON 没有从 JSON 文件中检索所有值?
问题描述
我正在编写一个程序来尝试使用 GSON 从 JSON 文件中检索值,但是,我注意到 GSON 无法检索我的所有值。例如,在 Eclipse 中进入调试模式,我发现大多数值都是空的。
调试模式: Eclipse 调试模式下访问变量时的图片
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 shoeName、shoePrice 等。
读取JSON.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。
鞋子.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。
鞋类.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?
解决方案
我找到了解决这个问题的方法。对于使用 GSON 进行 JSON 解析器的人,请确保检查变量名并确保它们与 JSON 文件中的变量名匹配,否则它们将为空。谢谢萨马布德!
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