Java 自定义JSON解析(Gson)
如何自定义特定字段的序列化/反序列化 以下是我的json:Java 自定义JSON解析(Gson),java,json,gson,Java,Json,Gson,如何自定义特定字段的序列化/反序列化 以下是我的json: [{ "Short Name": "X", "Address": "X Address", "Latitude": 40.739982, "Longitude": -73.978053, "Type": "A, B" }, { "Short Name": "Y", "Address": "Y Address", "Latitude": 40.852856, "Longitude": -73.938098, "Type": "A, B,
[{
"Short Name": "X",
"Address": "X Address",
"Latitude": 40.739982,
"Longitude": -73.978053,
"Type": "A, B"
},
{
"Short Name": "Y",
"Address": "Y Address",
"Latitude": 40.852856,
"Longitude": -73.938098,
"Type": "A, B, C, D"
}]
使用Gson,现在我可以解析json并使用
字符串类型
但是我想拆分类型字符串并获得类型字符串[]
public class MyClass {
@SerializedName("Short Name")
@Expose
private String ShortName;
@Expose
private String Address;
@Expose
private Double Latitude;
@Expose
private Double Longitude;
@Expose
private String Type;
// how can I split the string
// and get private String[] Type;
// when deserializing
}
简单。Json允许您使用数字(Int/Long/Double)、字符串、列表或对象。你需要的是一份清单 JSON: “类型”:{ “类型”:“数组”, “项”:{“类型”:“字符串”} } e、 g.“类型”:[“A”、“B”、“C”、“D”] 爪哇:
List<String> Type;
列表类型;
稍后,您可以使用任何Java列表实现,如ArrayList
e、 g.Type=newarraylist() 您需要实现一个自定义类型适配器 您可以这样做:
JsonDeserializer<String[]> deserializer = new JsonDeserializer<String[]>() {
@Override
public String[] deserialize(JsonElement jsonElem, Type type,
JsonDeserializationContext context) throws JsonParseException {
if(jsonElem == null) {
return null;
}
return jsonElem.getAsString().split(", ");
}
};
Gson gson = new GsonBuilder()
.registerTypeAdapter(String[].class, deserializer)
.create();
Type listType = new TypeToken<ArrayList<MyClass>>() {}.getType();
List<MyClass> t = gson.fromJson(json, listType);
致:
同样,如果需要序列化MyClass对象以将“Type”数组转换为逗号分隔的字符串,则可以添加序列化程序 您可以使用JsonAdapter来实现这一点。 以下是来自ducumentation的示例
Here is an example of how this annotation is used:
@JsonAdapter(UserJsonAdapter.class)
public class User {
public final String firstName, lastName;
private User(String firstName, String lastName) {
this.firstName = firstName;
this.lastName = lastName;
}
}
public class UserJsonAdapter extends TypeAdapter<User> {
@Override public void write(JsonWriter out, User user) throws IOException {
// implement write: combine firstName and lastName into name
out.beginObject();
out.name("name");
out.value(user.firstName + " " + user.lastName);
out.endObject();
// implement the write method
}
@Override public User read(JsonReader in) throws IOException {
// implement read: split name into firstName and lastName
in.beginObject();
in.nextName();
String[] nameParts = in.nextString().split(" ");
in.endObject();
return new User(nameParts[0], nameParts[1]);
}
}
可以在一个字段、该字段的类型和com.google.gson.GsonBuilder中指定不同的类型适配器。字段注释优先于GsonBuilder注册的类型适配器,后者又优先于带注释的类型
此注释引用的类必须是TypeAdapter或TypeAdapterFactory,或者必须实现JsonDeserializer或JsonSerializer中的一个或两个。使用TypeAdapterFactory可以委托给封闭的Gson实例。这不是问题的解决方案。他需要反序列化数组中逗号分隔的一串值。这不是一个json数组:“Type”:“a,B,C,D”我认为关键是他应该更改他的json,使“Type”实际上是一个json数组。这将为他提供一个更清晰的实现,而不是将数组隐藏在逗号分隔的字符串中。谢谢。我试试这个,然后告诉你。
@Expose
private String[] Type;
Here is an example of how this annotation is used:
@JsonAdapter(UserJsonAdapter.class)
public class User {
public final String firstName, lastName;
private User(String firstName, String lastName) {
this.firstName = firstName;
this.lastName = lastName;
}
}
public class UserJsonAdapter extends TypeAdapter<User> {
@Override public void write(JsonWriter out, User user) throws IOException {
// implement write: combine firstName and lastName into name
out.beginObject();
out.name("name");
out.value(user.firstName + " " + user.lastName);
out.endObject();
// implement the write method
}
@Override public User read(JsonReader in) throws IOException {
// implement read: split name into firstName and lastName
in.beginObject();
in.nextName();
String[] nameParts = in.nextString().split(" ");
in.endObject();
return new User(nameParts[0], nameParts[1]);
}
}
private static final class Gadget {
@JsonAdapter(UserJsonAdapter2.class)
final User user;
Gadget(User user) {
this.user = user;
}
}