使用杰克逊数据绑定解析Yaml会导致MismatchedInputException

Question

我要阅读的Yaml格式如下

- name: storage
  scm: git
  src: git+https://bitbucket.org/cer/linux_storage_jenkins.git
  version: '5'
- name: linux_jenkins
  scm: git
  src: git+https://bitbucket.org/cer/linux_jenkins.git
  version: '8'

我的模型很简单

public class Requirementsyml {
    //setter and getter in place
    private List<Requirement> items;
}

public class Requirement {
    private String name;
    private String scm;
    private String src;
    private String version;
}

我正在尝试阅读yaml内容，如下所示：

ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
Requirementsyml req = mapper.readValue(yaml_file_content, Requirementsyml.class);

但是我收到以下异常com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of Requirementsyml out of START_ARRAY token

由于模型具有列表，我认为输入不应该不匹配。 我试图将yaml文件作为java文件对象提供，而不是将其内容作为字符串提供。 结果保持不变。 我想念什么？

Answer 1

yaml结构应具有items数组/列表

items:
- name: storage
  scm: git
  src: git+https://bitbucket.org/cer/linux_storage_jenkins.git
  version: '5'
- name: linux_jenkins
  scm: git
  src: git+https://bitbucket.org/cer/linux_jenkins.git
  version: '8'

否则，您可以将其作为要求列表阅读而无需更改yaml

@Test
void test() throws IOException {
    ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
    List<Requirement> requirements = mapper.readValue(new File("src/test/resources/requirements.yml"), new TypeReference<List<Requirement>>() {});
    assertEquals(2, requirements.size());
}

还请确保Requirement和其他类没有args构造函数，否则在ObjectMapper上设置适当的标志