无法从 START_OBJECT 令牌反序列化 `java.lang.String` 的实例
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Cannot deserialize instance of `java.lang.String` out of START_OBJECT token
提问by robbie70
I am getting the below error message, can someone please help or suggest how best to debug this.
我收到以下错误消息，有人可以帮忙或建议如何最好地调试它。
Cannot deserialize instance of
java.lang.Stringout of START_OBJECT token at [Source: (PushbackInputStream); line: 1, column: 37610] (through reference chain: com.model.ProductList["products"]->java.util.ArrayList[23]->com.model.Product["price"]->com.Price["now"])
无法
java.lang.String在 [Source: (PushbackInputStream);反序列化超出 START_OBJECT 令牌的实例；行：1，列：37610]（通过参考链：com.model.ProductList["products"]->java.util.ArrayList[23]->com.model.Product["price"]->com.Price [“现在”]）
I am trying to deserialise a Products object from a REst API call. The code has been working fine until I added code to deserialise a Price sub-class. This looks as follows,
我正在尝试从 REst API 调用反序列化 Products 对象。代码一直运行良好，直到我添加了反序列化 Price 子类的代码。这看起来如下，
"price": {
"was": "",
"then1": "",
"then2": "",
"now": "59.00",
"uom": "",
"currency": "GBP"
},
My Price pojo looks as follows,
我的价格 pojo 如下所示，
public class Price {
@JsonProperty("was")
String was;
@JsonProperty("then1")
String then1;
@JsonProperty("then2")
String then2;
@JsonProperty("now")
String now;
@JsonProperty("uom")
String uom;
@JsonProperty("currency")
String currency;
public Price() {
//blank constructor for JSON
}
@Override
public String toString() {
return "Price{" +
"was='" + was + '\'' +
", then1='" + then1 + '\'' +
", then2='" + then2 + '\'' +
", now='" + now + '\'' +
", uom='" + uom + '\'' +
", currency='" + currency + '\'' +
'}';
}
}
I have written a Junit test to try and simulate the error but it works in my test,
我已经编写了一个 Junit 测试来尝试模拟错误，但它在我的测试中有效，
@Test
public void shouldConvertJsonProductListIntoPrice() {
ObjectMapper objectMapper = new ObjectMapper();
String content3 = "{\"products\": [{\"productId\": \"3525085\",\"title\": \"hush Tasha Vest Dress\", " +
"\"price\": {\"was\": \"\",\"then1\": \"\",\"then2\": \"\",\"now\": \"59.00\",\"uom\": \"\",\"currency\": \"GBP\"}, " +
"\"colorSwatches\": [{\"basicColor\": \"Red\",\"skuId\": \"237494589\"},{\"basicColor\": \"Blue\",\"skuId\": \"237494562\"}] " +
"}]}";
JavaType valueType = objectMapper.constructType(ProductList.class);
ProductList readValue;
try {
readValue = objectMapper.readValue(content3, valueType);
assertEquals("3525085", readValue.getProductList().get(0).productId);
assertEquals("hush Tasha Vest Dress", readValue.getProductList().get(0).title);
assertEquals("", readValue.getProductList().get(0).price.then1);
assertEquals("59.00", readValue.getProductList().get(0).price.now);
assertEquals("Blue", readValue.getProductList().get(0).colorSwatches[1].basicColor);
assertEquals("237494562", readValue.getProductList().get(0).colorSwatches[1].skuId);
} catch (Exception e) {
e.printStackTrace();
fail();
}
}
If I comment out the "now" field then my RestAPI call works perfectly and I dont see the exception.So it seems that there is a problem with the "now" field and here I notice that its trying to convert "59.00" into a String. Could this be a problem for the Fasterxml converter ? do I need to help it maybe ?
如果我注释掉“now”字段，那么我的 RestAPI 调用就可以正常工作，并且我看不到异常。所以似乎“现在”字段有问题，在这里我注意到它试图将“59.00”转换为字符串。这可能是 Fasterxml 转换器的问题吗？我需要帮忙吗？
The Product class is as follows (although this is much reduced list of fields that I am receiving off the API call).
Product 类如下（尽管这是我从 API 调用中收到的字段列表大大减少了）。
public class Product {
@JsonProperty("productId")
String productId;
@JsonProperty("title")
String title;
@JsonProperty("colorSwatches")
ColorSwatch [] colorSwatches;
@JsonProperty("price")
Price price;
public Product(){
// blank required for Hymanson
}
public Product(String productId, String title, ColorSwatch[] colorSwatches, Price price){
this.productId = productId;
this.title = title;
this.colorSwatches = colorSwatches;
this.price = price;
}
采纳答案by Lo?c Le Doyen
The error states it expects a VALUE(VALUE_STRINGpreferably), whereas it gets a START_OBJECT, so your issue is probably coming from a json of the form
错误指出它需要一个VALUE（最好是VALUE_STRING），而它得到一个START_OBJECT，所以你的问题可能来自表单的 json
"price": {
"was": "",
"then1": "",
"then2": "",
"now": {
...
}
"uom": "",
"currency": "GBP"
},
Instead of the "now": "some value"form expected by the code.
而不是"now": "some value"代码期望的形式。
