java - 在Java中解析JSON返回空结果

Question

我正在尝试使用 Java 解析 JSON，但没有得到预期的结果。 示例 json:

            "productId": "NDAtOS0wLS0=",
            "branchId": 5,
            "branchCustomers":[
                {"branchId":615,"customerNumber":4918,"products":[]},
                {"branchId":615,"customerNumber":9753,"products":[]},
                {"branchId":615,"customerNumber":9761,"products":[]}
            ],
            "customerNumber": 240,
            "subAccountNumber": 0,
            "productType": 9,
            "openingDate": "2016-10-02",
            "values":             [
                              {
                  "key": "accountingMethod",
                  "value": "1"
               },
                              {
                  "key": "accountType",
                  "value": "1"
               },
                              {
                  "key": "assetCashAccountId-branchId",
                  "value": "615"
               },
                              {
                  "key": "assetCashAccountId-customerNumber",
                  "value": "4041240"
               },
                              {
                  "key": "assetCashAccountId-subAccountNumber",
                  "value": "2"
               },
                              {
                  "key": "assetMarginAccountId-branchId",
                  "value": "615"
               },
                              {
                  "key": "assetMarginAccountId-customerNumber",
                  "value": "4041240"
               },
                              {
                  "key": "assetMarginAccountId-subAccountNumber",
                  "value": "2"
               },
                              {
                  "key": "blockingAmount",
                  "value": "1000000"
               },
                              {
                  "key": "collateral",
                  "value": "C"
               },
                              {
                  "key": "collateralBlockingType",
                  "value": "1"
               },
                              {
                  "key": "executingSecurityAccountId-branchId",
                  "value": "615"
               },
                              {
                  "key": "executingSecurityAccountId-customerNumber",
                  "value": "4041240"
               },
                              {
                  "key": "executingSecurityAccountId-subAccountNumber",
                  "value": "0"
               },
                              {
                  "key": "limit",
                  "value": "1000000"
               },
                              {
                  "key": "marginAccountId-branchId",
                  "value": "0"
               },
                              {
                  "key": "marginAccountId-customerNumber",
                  "value": "0"
               },
                              {
                  "key": "marginAccountId-subAccountNumber",
                  "value": "0"
               },
                              {
                  "key": "marginMarkup",
                  "value": "100"
               },
                              {
                  "key": "rolfNolanLedger",
                  "value": "B01429"
               },
                              {
                  "key": "settlementMethod",
                  "value": "1"
               }
            ]
         }
      ]
   }],
   "instances": []
}

并非所有 JSON 都具有这种结构，有些可能会丢失某些字段。我创建了一些 DTO 类来解析它。这是我的代码:

public class Response {

    private String partnerId;
    private byte branchId;
    private long customerNumber;
    private Long subAccountNumber;
    private Byte productType;
    private String openingDate;
    private String closingDate;
    private List<Values> values;
    private List<Instances> instances;
    private List<BranchCustomers> branchCustomers;


    public String getProductid() {
        return partnerId;
    }

    public void setProductid(String productid) {
        this.partnerId = productid;
    }

    public byte getBranchid() {
        return branchId;
    }

    public void setBranchid(byte branchid) {
        this.branchId = branchid;
    }

    public long getCustomernumber() {
        return customerNumber;
    }

    public void setCustomernumber(long customernumber) {
        this.customerNumber = customernumber;
    }

    public Long getSubaccountnumber() {
        return subAccountNumber;
    }

    public void setSubaccountnumber(Long subAccountNumber) {
        this.subAccountNumber = subAccountNumber;
    }

    public Byte getProducttype() {
        return productType;
    }

    public void setProducttype(Byte productType) {
        this.productType = productType;
    }

    public String getOpeningdate() {
        return openingDate;
    }

    public void setOpeningdate(String openingDate) {
        this.openingDate = openingDate;
    }

    public String getClosingdate() {
        return closingDate;
    }

    public void setClosingdate(String closingDate) {
        this.closingDate = closingDate;
    }

    public List<Values> getValues() {
        return values;
    }

    public void setValues(List<Values> values) {
        this.values = values;
    }

    public List<Instances> getInstances() {
        return instances;
    }

    public void setInstances(List<Instances> instances) {
        this.instances = instances;
    }

    public List<BranchCustomers> getBranchCustomers() {
        return branchCustomers;
    }

    public void setBranchCustomers(List<BranchCustomers> branchCustomers) {
        this.branchCustomers = branchCustomers;
    }
}

public class BranchCustomers {

    private byte branchId;
    private long customerNumber;
    private List<Products> products;

    public byte getBranchid() {
        return branchId;
    }

    public void setBranchid(byte branchId) {
        this.branchId = branchId;
    }

    public long getCustomernumber() {
        return customerNumber;
    }

    public void setCustomernumber(long customerNumber) {
        this.customerNumber = customerNumber;
    }

    public List<Products> getProducts() {
        return products;
    }

    public void setProducts(List<Products> products) {
        this.products = products;
    }
}

public void parseJson(String response) {
try{
    ObjectMapper mapper = new ObjectMapper();
    mapper.registerModule(new JavaTimeModule());
    mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    Response result = mapper.readValue(response, Response.class);
    System.out.println(result);

} catch (JsonMappingException e) {
    e.printStackTrace
} catch (JsonProcessingException e) {
    e.printStackTrace();
}

其他 DTO 类“Values”、“Instances”和“Products”此时为空，但我还不需要它们。问题是“结果”值具有正确的结构和正确的字段，但它们是 null 或 0，具体取决于它们的数据类型，而且我看不到我做错了什么。

有人可以帮助我吗？

Answer 1

您的 getter、setter 名称不正确。

举个例子，在您的 Response 对象中，您有 getProductid、getBranchid 和 getCustomernumber 以及类似的内容 setter 方法。但是，您的 JSON 包含 productId、branchId 和 customerNumber。它们有所不同，因为您没有使用正确的大小写。您应该使用驼峰命名法，这会将您的命名转换为 getProductId、getBranchId 和 getCustomerNumber。然后，它会匹配 JSON，并进行相应的映射。

这个:

public class Response {

private String partnerId;
private byte branchId;
private long customerNumber;
private Long subAccountNumber;
private Byte productType;
private String openingDate;
private String closingDate;
private List<BranchCustomers> branchCustomers;


public String getProductId() {
    return partnerId;
}

public void setProductId(String productid) {
    this.partnerId = productid;
}

public byte getBranchId() {
    return branchId;
}

public void setBranchId(byte branchid) {
    this.branchId = branchid;
}

public long getCustomerNumber() {
    return customerNumber;
}

public void setCustomerNumber(long customernumber) {
    this.customerNumber = customernumber;
}
...

导致:

Response{productId='NDAtOS0wLS0=', branchId=5, customerNumber=240 ...

作为旁注，我建议使用 IDE 自动生成样板代码，或者查看 Project Lombok只需添加注释即可生成样板代码。这也可以防止您犯命名错误。

此外，尝试为每个 pojo 获取一个 toString 方法，因为它将在日志记录或调试期间为您提供帮助。