Question

我有一个只包含一个hasmap类型属性的对象。

public class Application {

    private Map<String,Object> map2;

    public Map<String, Object> getMap2() {
        return Collections.unmodifiableMap(map2);
    }

    public void setMap2(Map<String, Object> map2) {
        this.map2 = map2;
    }
}

我尝试用杰克逊生成XML：

Map<String,Object> map = new HashMap<String, Object>();
map.put("key1", "value1");
map.put("key2", "value2");

XmlMapper xmlMapper = new XmlMapper();
xmlMapper.configure( ToXmlGenerator.Feature.WRITE_XML_DECLARATION, true );
System.out.println(xmlMapper.writeValueAsString(app));

结果是：

<?xml version='1.0' encoding='UTF-8'?>
<Application>
    <Map2>
        <key1>value1</key1>
        <key2>value2</key2>
    </Map2>
</Application>

但我想只有：

<?xml version='1.0' encoding='UTF-8'?>
<Application>
    <key1>value1</key1>
    <key2>value2</key2>
</Application>

如何删除Map2元素？

Answer 1

使用HashMap而不是整个类。像

public class AppDao {

    private Map<String,Object> Application;

    public Map<String, Object> getMap2() {
        return Collections.unmodifiableMap(map2);
    }

    public void setMap2(Map<String, Object> Application) {
    this.Application = Application;
    }
    public Map<String,Object> getMap2(){
        return Application;
    }
}

现在使用hashmap生成XML

xmlMapper.configure( ToXmlGenerator.Feature.WRITE_XML_DECLARATION, true );
System.out.println(xmlMapper.writeValueAsString(app.getMap2()));

Answer 2

我认为最好的选择是使用@JsonAnyGetter上方的getMap2()注释。是的，它的json注释，但你必须将它用于xml和json https://github.com/FasterXML/jackson-dataformat-xml#additional-annotations

public static class Application {

    private Map<String,Object> map2;

    @JsonAnyGetter
    public Map<String, Object> getMap2() {
        return Collections.unmodifiableMap(map2);
    }

    public void setMap2(Map<String, Object> map2) {
        this.map2 = map2;
    }

    // if you need deserialization
    @JsonAnySetter
    public void setMap2(String key, Object value) {
        map2.put(key, value);
    }
}

2-nd Option（如果你可以改变你的结构）是使用

public static class Application extends HashMap<String,Object> {}

// or if you want to change map class name:
@JsonRootName("Application")
public static class MyMap  extends HashMap<String,Object>{}

使用Jackson将带有hasmap的Object转换为XML

2 个答案: