泽西和杰克逊的子类序列化不包括额外的属性 [英] Jersey and Jackson serialization of subclasses does not include extra attributes

问题描述

在Jersey中，当使用Jackson进行JSON序列化时，不包括实现子类的额外属性。例如，给定以下类结构

In Jersey, when using Jackson for JSON serialization, the extra attributes of an implementing subclass are not included. For example, given the following class structure

@JsonTypeInfo(use=JsonTypeInfo.Id.NAME, include=JsonTypeInfo.As.PROPERTY, property="@class")
@JsonSubTypes({
    @JsonSubTypes.Type(value = Foo.class, name = "foo")
}
public abstract class FooBase {
    private String bar;

    public String getBar() {
        return bar;
    }

    public void setBar( String bar ) {
        this.bar = bar;
    }
}

public class Foo extends FooBase {
    private String biz;

    public String getBiz() {
        return biz;
    }

    public void setBiz( String biz ) {
        this.biz = biz;
    }
}

以下泽西岛代码

@GET
public FooBase get() {
   return new Foo();
}

我收回以下json

{"@class" => "foo", "bar" => null}

但我真正想要的是

{"@class" => "foo", "bar" => null, "biz" => null}

此外，在我的web.xml中，我启用了POJOMappingFeature 解决此问题

Also, in my web.xml I have enabled POJOMappingFeature to solve this issue

<init-param>
    <param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
    <param-value>true</param-value>
</init-param>

编辑：修复Java代码以正确设置setter并使Foo不抽象

Fixed the Java code to have the setters set properly and Foo to not be abstract

推荐答案

它应该像你展示的那样工作;有一个可能的例外：如果启用JAXB注释（仅限），JAXB限制要求只使用getter / setter对来检测属性。
所以尝试为'biz'添加setter，看看是否会改变它。

It should work as you show; with one possible exception: if you enable JAXB annotations (only), JAXB restrictions mandate that only getter/setter pairs are used to detect properties. So try adding setter for 'biz' and see if that changes it.

Jackson注释不会出现这种情况;理想情况下，如果你结合杰克逊和JAXB注释（我认为泽西启用了两者）。
如果还启用了Jackson注释处理，在'getBiz'旁边添加@JsonProperty也应该可以解决问题。

This would not occur with Jackson annotations; and ideally not if you combine Jackson and JAXB annotations (I thought Jersey enabled both). If Jackson annotation processing is also enabled, adding @JsonProperty next to 'getBiz' should also do the trick.

最后除非你需要JAXB注释，否则你可以只是恢复使用Jackson注释 - 在我看来，JAXB注释的主要用例是你需要生成XML和JSON，并使用JAXB（通过Jersey）来实现XML。否则它们对JSON没用。

Finally unless you need JAXB annotations, you could just revert to using Jackson annotations only -- in my opinion, the main use case for JAXB annotations is if you need to produce both XML and JSON, and use JAXB (via Jersey) for XML. Otherwise they aren't useful with JSON.

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