java.lang.ClassCastException：java.util.LinkedHashMap无法强制转换为com.testing.models.Account [英] java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to com.testing.models.Account

问题描述

我收到以下错误：

java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to com.testing.models.Account

以下代码

final int expectedId = 1;

Test newTest = create();

int expectedResponseCode = Response.SC_OK;

ArrayList<Account> account = given().when().expect().statusCode(expectedResponseCode)
    .get("accounts/" + newTest.id() + "/users")
    .as(ArrayList.class);
assertThat(account.get(0).getId()).isEqualTo(expectedId);

我有什么理由不能做 get（0）？

推荐答案

这个问题来自杰克逊。如果没有关于要反序列化的类的足够信息，它使用 LinkedHashMap 。

The issue's coming from Jackson. When it doesn't have enough information on what class to deserialize to, it uses LinkedHashMap.

由于你没有通知杰克逊你的 ArrayList 的元素类型，它不知道你想要反序列化为帐户的 ArrayList 。所以它回退到默认值。

Since you're not informing Jackson of the element type of your ArrayList, it doesn't know that you want to deserialize into an ArrayList of Accounts. So it falls back to the default.

相反，您可以使用作为（JsonNode.class），并且然后以比确定允许更丰富的方式处理 ObjectMapper 。这样的事情：

Instead, you could probably use as(JsonNode.class), and then deal with the ObjectMapper in a richer manner than rest-assured allows. Something like this:

ObjectMapper mapper = new ObjectMapper();

JsonNode accounts = given().when().expect().statusCode(expectedResponseCode)
    .get("accounts/" + newClub.getOwner().getCustId() + "/clubs")
    .as(JsonNode.class);


//Jackson's use of generics here are completely unsafe, but that's another issue
List<Account> accountList = mapper.readValue(
    mapper.treeAsTokens(accounts), 
    new TypeReference<List<Account>>(){}
);

assertThat(accountList.get(0).getId()).isEqualTo(expectedId);

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