将 JSON 数据转换为 Java Object 时发生 MalformedJsonException

Question

在使用 Postman 测试 RESTEasy 的 @POST 方法时，出现错误MalformedJsonException

我的@POST 方法

@POST
    @Path("service/product")
    @Consumes("application/json")
    public Object setProductData(Product product) {
        String result = product.toString().trim();
        Gson gson = new Gson();
        Data.addProduct(gson.fromJson(result, Product.class));

        return Response.status(200).entity(result).build();
    }

我的 model

public class Product {
    private String id;
    private String name;
    private String image;
    private double price;
    private String catalogId;

    public Product(String id, String name, String image, double price, String catalogId) {
        this.id = id;
        this.name = name;
        this.image = image;
        this.price = price;
        this.catalogId = catalogId;
    }

    public Product() {
    }

    public String getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public String getImage() {
        return image;
    }

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

    public double getPrice() {
        return price;
    }

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

    public String getCatalogId() {
        return catalogId;
    }

    public void setCatalogId(String catalogId) {
        this.catalogId = catalogId;
    }

    @Override
    public String toString() {
        return "{" +
                "id='" + id + ',' +
                "name='" + name + ',' +
                "image='" + image + ',' +
                "price='" + price + ',' +
                "catalogId='" + catalogId + ',' + "}";
    }
}

这就是我要添加的内容： https://i.imgur.com/XACBopY.png

数据为json格式， {"id":"band1","name":"Mi Band 4","image":"https://i.imgur.com/7MLMnhW.jpg","price":30.0,"catalogId":"abc1"}例如

错误： https://i.imgur.com/8suya35.png

早些时候我收到错误Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $但后来我意识到产品 class 中的toString()方法是问题所在，我修复了它并在问题中产生了错误。

请帮我解决这个错误。

Answer 1

您的 toString() 一开始就有问题 - Json 公式不正确。 如果您想使用 toString() 将 POJO 转换为 JSON，请在 toString 中使用 apache commons lang3 的 JSON 样式。

import com.google.gson.Gson;
import org.apache.commons.lang3.builder.ToStringBuilder;
import org.apache.commons.lang3.builder.ToStringStyle;

public class Test1 {

    public static void main(String[] args) {
        Product product = new Product("1", "someone", "https://url", 1.23, "11");
        System.out.println(product);

        Gson gson = new Gson();
        Product product1 = gson.fromJson(product.toString().trim(), Product.class);
        System.out.println(product1);
    }

    private static class Product {
        private String id;
        private String name;
        private String image;
        private double price;
        private String catalogId;

        public Product() {
        }

        public Product(String id, String name, String image, double price, String catalogId) {
            this.id = id;
            this.name = name;
            this.image = image;
            this.price = price;
            this.catalogId = catalogId;
        }

        @Override
        public String toString() {
            return new ToStringBuilder(this, ToStringStyle.JSON_STYLE)
                    .append("id", id)
                    .append("name", name)
                    .append("image", image)
                    .append("price", price)
                    .append("catalogId", catalogId)
                    .toString();
        }

        public String getId() {
            return id;
        }

        public Product setId(String id) {
            this.id = id;
            return this;
        }

        public String getName() {
            return name;
        }

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

        public String getImage() {
            return image;
        }

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

        public double getPrice() {
            return price;
        }

        public Product setPrice(double price) {
            this.price = price;
            return this;
        }

        public String getCatalogId() {
            return catalogId;
        }

        public Product setCatalogId(String catalogId) {
            this.catalogId = catalogId;
            return this;
        }
    }
}

output如下：-

{"id":"1","name":"someone","image":"https://url","price":1.23,"catalogId":"11"} {"id":"1 ","name":"someone","image":"https://url","price":1.23,"catalogId":"11"}

现在，开始使用。 如果您将 object 作为输入本身作为 POST 请求正文，那么为什么不简单地使用“Data.addProduct(product);”呢？