java - Jackson - 展开嵌套属性

Question

我有一个像这样的 xml

<TopLevel attr1="foo">
    <Midlevel attr2="bar">
        <BottomLevel>
            <data1>blahblah</data1>
            <data2>blahblah</data2>
        </BottomLevel>
        ...more bottom level elements...
    </Midlevel>
...moreMidLevelElements...
</TopLevel>

现在我知道 @JsonUnwrapped 注释可以帮助提升一个级别(它在所有示例中都显示)。但是，当我尝试反序列化捕获外层属性的 BottomLevel 对象时，我只得到所有内容的空值。

谁能帮我压平这个 xml 吗？我试图概括这个问题。理想情况下，最终结果是 List

我的 pojo 有字段数据1数据2属性1属性2

Answer 1

不要认为这是这个问题的完美答案，但它可以帮助解决您遇到的问题。 (以一种黑客的方式)

public static void main(String[] args) throws IOException {
    String xml = "<TopLevel attr1=\"foo\">\n" +
            "    <Midlevel attr2=\"bar\">\n" +
            "        <BottomLevel>\n" +
            "            <data1>blahblah</data1>\n" +
            "            <data2>blahblah</data2>\n" +
            "        </BottomLevel>\n" +
            "    </Midlevel>\n" +
            "    <Midlevel attr2=\"bar2\">\n" +
            "        <BottomLevel>\n" +
            "            <data1>blahblah2</data1>\n" +
            "            <data2>blahblah2</data2>\n" +
            "        </BottomLevel>\n" +
            "    </Midlevel>\n" +
            "</TopLevel>";

    ObjectMapper xmlMapper = new XmlMapper();
    System.out.println(xmlMapper.readValue(xml, TopLevel.class)); //Once here, you can now do custom mapping with the TopLevel class object to your custom POJO
}

@JsonIgnoreProperties(ignoreUnknown = true)
static class TopLevel {

    @JacksonXmlProperty(isAttribute = true)
    private String attr1;

    @JacksonXmlElementWrapper(localName = "Midlevel", useWrapping = false)
    @JacksonXmlProperty(localName = "Midlevel")
    private List<MidLevel> midLevel = new ArrayList<>();

    @Override
    public String toString() {
        return "TopLevel{" +
                "attr1='" + attr1 + '\'' +
                ", midLevel=" + midLevel +
                '}';
    }
}

static class MidLevel {

    @JacksonXmlProperty(isAttribute = true)
    private String attr2;

    @JacksonXmlElementWrapper(localName = "BottomLevel", useWrapping = false)
    @JacksonXmlProperty(localName = "BottomLevel")
    private List<BottomLevel> bottomLevels = new ArrayList<>();

    @Override
    public String toString() {
        return "MidLevel{" +
                "attr2='" + attr2 + '\'' +
                ", bottomLevels=" + bottomLevels +
                '}';
    }
}

static class BottomLevel {

    @JacksonXmlProperty(localName = "data1")
    private String data1;

    @JacksonXmlProperty(localName = "data2")
    private String data2;

    @Override
    public String toString() {
        return "BottomLevel{" +
                "data1='" + data1 + '\'' +
                ", data2='" + data2 + '\'' +
                '}';
    }
}