没有single-int-arg构造函数/工厂方法 [英] no single-int-arg constructor/factory method

问题描述

我有这个代码：

final Person p = new Person(1L);
final ObjectMapper mapper = JacksonUtil.INSTANCE.getMapper();
final TypeReference<HashMap<String, Object>> typeMap = new TypeReference<HashMap<String, Object>>() {};
final String personJson= mapper.writeValueAsString(p);
mapper.readValue(personJson, typeMap);

personJson 如：

"id" : 1

每当我在Json中有一个 Long类型时，当我尝试读取它时它不起作用。我有这个错误：

Whenever I have a Long type in my Json, it doesn't work when I try to read it. I have this error:

com.fasterxml.jackson.databind.JsonMappingException：
不能实例化类型的值[simple type ，类
org.codehaus.jackson.generated.java.lang.Number]来自积分号;
没有单个int-arg构造函数/工厂方法

com.fasterxml.jackson.databind.JsonMappingException: Can not instantiate value of type [simple type, class org.codehaus.jackson.generated.java.lang.Number] from Integral number; no single-int-arg constructor/factory method

如何让它接受类型龙？是否在mapper中启用了哪些功能？

How can I make it accept the type Long? Is there any feature to enable in the mapper?

推荐答案

在Person中创建一个接受整数的构造函数（而不是长整型）你做）。如果你肯定想接受long，那么尝试创建一个接受Number的构造函数。

Create a constructor in Person that accepts an integer (and not a long as you do). If you definitely want to accept a long then try to create a constructor that accepts a Number.

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