如何映射Mixins以嵌套JSON响应

我使用Jackson API将我的JSON响应映射到java对象 。 例如，

回复{name：’karthikeyan’，年龄：’24’，性别：’男’}

@JsonProperty("name") public String _name; @JsonProperty("age") public int _age; @JsonProperty("gender") public String _gender; 

是混合，它工作正常。（内部我们将映射这个pojo和混合）。 现在我如何在混合中表示以下响应？

 { name :'karthikeyan', age:'24', gender:'Male', interest: { books:'xxx', music:'yyy', movie:'zzz' } } 

我试过以下，但没有运气。

 @JsonProperty("name") public String _name; @JsonProperty("age") public int _age; @JsonProperty("gender") public String _gender; @JsonProperty("interest") public InterestPojo interestPojo; //created same format mix-in and pojo for interest params as well. 

但无法准确地映射它们，请提出您的意见和想法如何做到这一点？

Answer 1

我尝试了以下方法：

  ObjectMapper mapper = new ObjectMapper(); System.out.println(mapper.writeValueAsString(new Something("Name", 12, "male", new Nested("books", "Music", "Movie")))); public class Something { @JsonProperty("name") public String name; @JsonProperty("age") public int age; @JsonProperty("gender") public String gender; @JsonProperty("interest") public Nested nested; //Constructor } public class Nested { @JsonProperty("books") public String books; @JsonProperty("music") public String music; @JsonProperty("movie") public String movie; //Constructor } 

输出是：

 { "name":"Name", "age":12, "gender":"male", "interest": { "books":"books", "music":"Music", "movie":"Movie" } } 

所以一切都按预期工作。 我已经检查过，如果你提供了一些setter和getters，并设置了私有字段的可见性，那是否有区别，但这没有什么区别。

也许您想向我们展示您的InterestPojo或您的输出/堆栈跟踪？

编辑：好的，我想我明白了;）

我尝试了以下方法：

 public void start() throws IOException { ObjectMapper mapper = new ObjectMapper(); mapper.getSerializationConfig().addMixInAnnotations(Something.class, Nested.class); mapper.getDeserializationConfig().addMixInAnnotations(Something.class, Nested.class); System.out.println(mapper.writeValueAsString(new Something("Name", 12, "male", new NestedImpl("name", null)))); } public final class Something { private final String name; private int age; private String gender; // thats your interest thing public Nested nested; public Something(String name, int age, String gender, Nested nested) { this.name = name; this.age = age; this.gender = gender; this.nested = nested; } String getName() { return name; } Nested getNested() { return nested; } } public abstract class Nested { @JsonProperty("name-ext") abstract String getName(); @JsonProperty("interest-ext") abstract Nested getNested(); } public class NestedImpl extends Nested { private String name; private Nested nested; private NestedImpl(String name, Nested nested) { this.name = name; this.nested = nested; } @Override String getName() { return name; } @Override Nested getNested() { return nested; } } 

输出：

 { "age":12, "gender":"male", "name-ext":"Name", "interest-ext": { "name-ext":"name", "interest-ext":null } } 

这不完全是你的结构，但我认为这就是你想要的。 我对吗？

EDIT2：我使用JSON-> Object和Object-> JSON测试了以下结构。

 ObjectMapper mapper = new ObjectMapper(); mapper.getSerializationConfig().addMixInAnnotations(Something.class, Mixin.class); mapper.getSerializationConfig().addMixInAnnotations(Nested.class, NestedMixin.class); mapper.getDeserializationConfig().addMixInAnnotations(Something.class, Mixin.class); mapper.getDeserializationConfig().addMixInAnnotations(Nested.class, NestedMixin.class); Nested nested = new Nested(); nested.setName("Nested"); nested.setNumber(12); Something some = new Something(); some.setName("Something"); some.setAge(24); some.setGender("Male"); some.setNested(nested); String json = mapper.writeValueAsString(some); System.out.println(json); Something some2 = mapper.readValue(json, Something.class); System.out.println("Object: " + some2); public abstract class Mixin { @JsonProperty("name") private String _name; @JsonProperty("age") private int _age; @JsonProperty("gender") private String _gender; @JsonProperty("interest") private Nested nested; } public class Something { private String _name; private int _age; private String _gender; private Nested nested; // You have to provide Setters and Getters!! } public abstract class NestedMixin { @JsonProperty("nameNested") private String name; @JsonProperty("numberNested") private int number; } public class Nested { private String name; private int number; // You have to provide Setters and Getters!! } 

输出： {"age":24,"gender":"Male","name":"Something","interest":{"nameNested":"Nested","numberNested":12}}

Object: Something{name=Something, age=24, gender=Male, nested=Nested{name=Nested, number=12}}

注意：杰克森似乎遇到了内部课程的问题。 因此，如果您在额外项目中测试该示例，请创建额外的类文件;）

编辑3：如果您使用的是模块，请尝试以下操作：

 public class JacksonMixinModule extends SimpleModule { public JacksonMixinModule() { super("JacksonMixinModule", new Version(0, 1, 0, "SNAPSHOT")); } @Override public void setupModule(SetupContext context) { super.setupModule(context); context.setMixInAnnotations(Something.class, Mixin.class); context.setMixInAnnotations(Nested.class, NestedMixin.class); } } 

…

 ObjectMapper mapper = new ObjectMapper(); mapper.registerModule(new JacksonMixinModule());