java - Jackson ObjectMapper 无法反序列化 POJO，抛出异常 : No suitable constructor found for type [. ..]:无法从 JSON 对象实例化

Question

我已尝试测试以下代码，但没有成功:

class TestClass
{
  private class ND2Customer
  {
    public String name;
    public String description;
    public String email;
    public Boolean multiuser;

    public String dnszone;
    public String uri;
    public String type;

    public ND2Customer()
    {

    }
  }

  @Test
  public void TestJackson() throws JsonParseException, JsonMappingException, IOException
  {
    String json="{\"description\": \"test1u\", \"dnszone\": \"test1.public.sevenltest.example.com.\", \"uri\": \"http://199.127.129.69/customer/test1\", \"multiuser\": true, \"type\": \"2.0.3-3146\", \"email\": \"test1@com.com\", \"name\": \"test1\"}";
    ObjectMapper mapper = new ObjectMapper();

    ND2Customer casted=mapper.readValue(json, ND2Customer.class);

    String castedback=mapper.defaultPrettyPrintingWriter().writeValueAsString(casted);
    System.out.println(castedback);
  } 
}

这个问题与这个不同: Deserializing JSON with Jackson - Why JsonMappingException "No suitable constructor"?

还有这个: JsonMappingException: No suitable constructor found for type [simple type, class ]: can not instantiate from JSON object

还有这个: JsonMappingException: No suitable constructor found for type [simple type, class ]: can not instantiate from JSON object

因为我手动覆盖了默认构造函数，它不是子类。

我该如何解决这个问题？

Answer 1

使其成为静态的。 Jackson 无法反序列化为内部类