JSON来的HashMap（杰克逊） [英] JSON to hashmap (Jackson)

问题描述

我想转换成JSON与杰克逊一个HashMap。这是我的JSON：

I want to convert JSON to a HashMap with Jackson. This is my JSON:

String json = "[{\"Opleidingen\":[{\"name\":\"Bijz. trajecten zorg en welzijn\",\"afk\":\"BTZW\",\"id\":\"0\"},{\"name\":\"Bouwkunde\",\"afk\":\"Bwk\",\"id\":\"14\"},{\"name\":\"Electrotechniek / mechatronica\",\"afk\":\"EltMe\",\"id\":\"15\"},{\"name\":\"Extern\",\"afk\":\"Extern\",\"id\":\"16\"},{\"name\":\"Gezondheidszorg\",\"afk\":\"Zorg\",\"id\":\"17\"},{\"name\":\"Handel\",\"afk\":\"Hand\",\"id\":\"18\"},{\"name\":\"Horeca\",\"afk\":\"Hor\",\"id\":\"19\"},{\"name\":\"Ict\",\"afk\":\"ICT\",\"id\":\"20\"},{\"name\":\"Maatschappelijke zorg\",\"afk\":\"MZ\",\"id\":\"21\"},{\"name\":\"Onderwijs assistent / pedagogisch werk\",\"afk\":\"OAPW\",\"id\":\"22\"},{\"name\":\"Tab / brug\",\"afk\":\"TAB\",\"id\":\"23\"},{\"name\":\"Werktuigbouw / maritieme techniek\",\"afk\":\"WtbMt\",\"id\":\"24\"},{\"name\":\"Zakelijke dienstverlening\",\"afk\":\"TAB\",\"id\":\"25\"}]},{\"Klassen\":[{\"name\":\"V2ZWA\",\"cat\":\"BTZW\",\"id\":\"1\"},{\"name\":\"V2ZWB\",\"cat\":\"Bwk\",\"id\":\"2\"},{\"name\":\"V2ZWB\",\"cat\":\"BTZW\",\"id\":\"3\"},{\"name\":\"V3B2A\",\"cat\":\"BTZW\",\"id\":\"3\"},{\"name\":\"V3B2B\",\"cat\":\"BTZW\",\"id\":\"4\"},{\"name\":\"V3B2C\",\"cat\":\"BTZW\",\"id\":\"5\"},{\"name\":\"V3B2D\",\"cat\":\"BTZW\",\"id\":\"6\"},{\"name\":\"V3B2E\",\"cat\":\"BTZW\",\"id\":\"7\"},{\"name\":\"V3B3A\",\"cat\":\"BTZW\",\"id\":\"8\"},{\"name\":\"V3B3B\",\"cat\":\"BTZW\",\"id\":\"9\"},{\"name\":\"V3B3C\",\"cat\":\"BTZW\",\"id\":\"10\"},{\"name\":\"VWA\",\"cat\":\"BTZW\",\"id\":\"11\"},{\"name\":\"VWB\",\"cat\":\"BTZW\",\"id\":\"12\"},{\"name\":\"VWC\",\"cat\":\"BTZW\",\"id\":\"13\"}]}]"; 

我想，我填，我得到的名称后面的ID，所以： result.get（13）; 收益 VWC 和 result.get（0）; 收益 Bijz。 trajecten ZORG恩welzijn 。

我试过这样：

try {
    @SuppressWarnings("unchecked")
    ArrayList<LinkedHashMap<?, ?>> result = new ObjectMapper().readValue(json, ArrayList.class);
    System.out.println(result.get(1).get("id"));
} catch (JsonParseException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (JsonMappingException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

但随后这是内容 result.get（1）; ：

I/System.out(809): {Klassen=[{name=V2ZWA, cat=BTZW, id=1}, {name=V2ZWB, cat=Bwk, id=2}, {name=V2ZWB, cat=BTZW, id=3}, {name=V3B2A, cat=BTZW, id=3}, {name=V3B2B, cat=BTZW, id=4}, {name=V3B2C, cat=BTZW, id=5}, {name=V3B2D, cat=BTZW, id=6}, {name=V3B2E, cat=BTZW, id=7}, {name=V3B3A, cat=BTZW, id=8}, {name=V3B3B, cat=BTZW, id=9}, {name=V3B3C, cat=BTZW, id=10}, {name=VWA, cat=BTZW, id=11}, {name=VWB, cat=BTZW, id=12}, {name=VWC, cat=BTZW, id=13}]}

另外，我已经试过了没有杰克逊：

Also I've tried it without Jackson:

for (int i = 0; i < jObject.length(); i++) {
       JSONArray opleidingen = jObject.getJSONObject(i).getJSONArray("Opleidingen");
       for (int i2 = 0; i2 < opleidingen.length(); i2++) {
           outMap.put(opleidingen.getJSONObject(i2).getString("id"), opleidingen.getJSONObject(i2).getString("name"));
       }
       JSONArray klassen = jObject.getJSONObject(i).getJSONArray("Klassen");
       for (int i3 = 0; i3 < klassen.length(); i3++) {
           outMap.put(klassen.getJSONObject(i3).getString("id"), klassen.getJSONObject(i3).getString("name"));
       }
}

但是，这既不是工作。

But that is neither working.

是否有可能我的JSON转换为一个HashMap（并且给出ID，当它返回的名称）？

Is it possible to convert my JSON to a HashMap (and when ID is given that it returns the name)?

（ArrayList类可以发现这里）

(ArrayList class can be found here)

推荐答案

我想，你应该如何检索末名的方式分开反序列化逻辑。对于反序列化作为笑着方法，你可以。例如，您可以创建描述您的JSON POJO类。参见下面的例子。 POJO类：

I think, you should separate deserialization logic from the way how to retrieve names at the end. For deserialization use as simle method as you can. For example, you can create POJO classes which describe your JSON. See below example. POJO classes:

class EntitiesOwner {

    private String name;
    private List<Entity> entities;

    @JsonAnySetter
    public void setProperties(String name, List<Entity> entities) {
        this.name = name;
        this.entities = entities;
    }

    public String getName() {
        return name;
    }

    public List<Entity> getEntities() {
        return entities;
    }

    @Override
    public String toString() {
        return "EntitiesOwner [name=" + name + ", entities=" + entities + "]";
    }
}

class Entity {

    private int id;
    private String afk;
    private String name;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getAfk() {
        return afk;
    }

    public void setAfk(String afk) {
        this.afk = afk;
    }

    public void setCat(String cat) {
        this.afk = cat;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "Entity [id=" + id + ", afk=" + afk + ", name=" + name + "]";
    }
}

现在您可以轻松地反序列化是这样的：

Now you can easily deserialize it in this way:

ObjectMapper mapper = new ObjectMapper();

EntitiesOwner[] owners = mapper.readValue(json, EntitiesOwner[].class);
System.out.println(Arrays.toString(owners));

以上程序打印：

[EntitiesOwner [name=Opleidingen, entities=[Entity [id=0, afk=BTZW, name=Bijz. trajecten zorg en welzijn], Entity [id=14, afk=Bwk, name=Bouwkunde], Entity [id=15, afk=EltMe, name=Electrotechniek / mechatronica], Entity [id=16, afk=Extern, name=Extern], Entity [id=17, afk=Zorg, name=Gezondheidszorg], Entity [id=18, afk=Hand, name=Handel], Entity [id=19, afk=Hor, name=Horeca], Entity [id=20, afk=ICT, name=Ict], Entity [id=21, afk=MZ, name=Maatschappelijke zorg], Entity [id=22, afk=OAPW, name=Onderwijs assistent / pedagogisch werk], Entity [id=23, afk=TAB, name=Tab / brug], Entity [id=24, afk=WtbMt, name=Werktuigbouw / maritieme techniek], Entity [id=25, afk=TAB, name=Zakelijke dienstverlening]]], EntitiesOwner [name=Klassen, entities=[Entity [id=1, afk=BTZW, name=V2ZWA], Entity [id=2, afk=Bwk, name=V2ZWB], Entity [id=3, afk=BTZW, name=V2ZWB], Entity [id=3, afk=BTZW, name=V3B2A], Entity [id=4, afk=BTZW, name=V3B2B], Entity [id=5, afk=BTZW, name=V3B2C], Entity [id=6, afk=BTZW, name=V3B2D], Entity [id=7, afk=BTZW, name=V3B2E], Entity [id=8, afk=BTZW, name=V3B3A], Entity [id=9, afk=BTZW, name=V3B3B], Entity [id=10, afk=BTZW, name=V3B3C], Entity [id=11, afk=BTZW, name=VWA], Entity [id=12, afk=BTZW, name=VWB], Entity [id=13, afk=BTZW, name=VWC]]]]

有关解决我提议创建新的类，它可以帮你这个实体。例如：

For resolving entities I propose to create new class which can help you with this. For example:

class EntityResolver {

    private Map<Integer, Entity> entities;

    public EntityResolver(EntitiesOwner[] owners) {
        entities = new HashMap<Integer, Entity>(owners.length);
        for (EntitiesOwner owner : owners) {
            for (Entity entity : owner.getEntities()) {
                entities.put(entity.getId(), entity);
            }
        }
    }

    public Entity getById(int id) {
        return entities.get(id);
    }
}

简单的用法：

EntityResolver resolver = new EntityResolver(owners);
System.out.println(resolver.getById(0).getName());
System.out.println(resolver.getById(13).getName());

以上程序打印：

Bijz. trajecten zorg en welzijn
VWC

这篇关于JSON来的HashMap（杰克逊）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！