java - 如何使用 auto-value-gson 映射未知的 json 字段
问题描述
我正在与他们的api对话的 android 中制作一个简单的 github gist view 应用程序。
但我不确定如何使用 AutoValue 和 GSON 来映射这个 json 响应。请注意,我已经删除了很多键,因为我目前不需要它,实际响应看起来像这样。
示例响应
[
{
"id": "3937809cf12adae05595c43c5ef4ce56",
"files": {
"main.css": {
"filename": "main.css",
"type": "text/css",
"language": "CSS",
"raw_url": "https://gist.githubusercontent.com/*/3937809cf12adae05595c43c5ef4ce56/raw/f46b97a4cf561fa18e50e14bed734eea78bc58d9/main.css",
"size": 102
},
"readme.txt": {
"filename": "readme.txt",
"type": "text/plain",
"language": "Text",
"raw_url": "https://gist.githubusercontent.com/*/3937809cf12adae05595c43c5ef4ce56/raw/aa7bf7046baaf58b23b4fa4c3b19a575d5eae36e/readme.txt",
"size": 192
}
}
}
]
问题
我读过我可以在String
和File
对象之间映射以使其工作。但它不起作用,因为files
key 是或可以是对象的对象。
那么如何使用 auto-value-gson 映射这些未知对象的对象呢?甚至可能吗?
代码
GistResponse.java
@AutoValue
public abstract class GistResponse {
@SerializedName("id")
public abstract String getId();
@SerializedName("files")
public abstract FileName getFileNameList();
public static Builder builder() {
return new AutoValue_GistResponse.Builder();
}
@AutoValue.Builder
public abstract static class Builder {
public abstract Builder setId(String value);
public abstract Builder setFileNameList(FileName value);
public abstract GistResponse build();
}
public static TypeAdapter<GistResponse> typeAdapter(Gson gson) {
return new AutoValue_GistResponse.GsonTypeAdapter(gson);
}
}
文件名.java
@AutoValue
public abstract class FileName {
public abstract Map<String, File> getFilesList();
public static Builder builder() {
return new AutoValue_FileName.Builder();
}
@AutoValue.Builder
public abstract static class Builder {
public abstract Builder setFilesList(Map<String, File> value);
public abstract FileName build();
}
public static TypeAdapter<FileName> typeAdapter(Gson gson) {
return new AutoValue_FileName.GsonTypeAdapter(gson);
}
}
文件.java
@AutoValue
public abstract class File {
@SerializedName("filename")
public abstract String getFileName();
@SerializedName("type")
public abstract String getType();
@SerializedName("language")
public abstract String getLanguage();
@SerializedName("raw_url")
public abstract String getRawUrl();
@SerializedName("size")
public abstract Integer getSize();
public static Builder builder() { return new AutoValue_File.Builder(); }
@AutoValue.Builder
public abstract static class Builder {
public abstract Builder setFileName(String value);
public abstract Builder setType(String value);
public abstract Builder setLanguage(String value);
public abstract Builder setRawUrl(String value);
public abstract Builder setSize(Integer value);
public abstract File build();
}
public static TypeAdapter<File> typeAdapter(Gson gson) {
return new AutoValue_File.GsonTypeAdapter(gson);
}
}
相关主题和信息:
解决方案
从那以后,我找到了一个解决方案,其中包括编写一个TypeAdapter
实际上非常简单的自定义。
这是代码:
public class FileTypeAdapter extends TypeAdapter {
@Override
public void write(JsonWriter out, Object value) throws IOException {}
@Override
public List<File> read(JsonReader jsonReader) throws IOException {
ArrayList<File> fileList = new ArrayList<>();
if (jsonReader.peek() == JsonToken.NULL) {
jsonReader.nextNull();
return fileList;
}
jsonReader.beginObject();
while (jsonReader.hasNext()) {
jsonReader.nextName();
if (jsonReader.peek() == JsonToken.NULL) {
jsonReader.nextNull();
continue;
}
File.Builder file = File.builder();
jsonReader.beginObject();
while (jsonReader.hasNext()) {
String nextName = jsonReader.nextName();
switch (nextName) {
case "filename": {
String nextString = jsonReader.nextString();
file.setFileName(nextString);
break;
}
case "type": {
String nextString = jsonReader.nextString();
file.setType(nextString);
break;
}
case "language": {
if (jsonReader.peek() == JsonToken.NULL) {
jsonReader.nextNull();
} else {
String nextString = jsonReader.nextString();
file.setLanguage(nextString);
}
break;
}
case "raw_url": {
String nextString = jsonReader.nextString();
file.setRawUrl(nextString);
break;
}
case "size": {
Integer nextInt = jsonReader.nextInt();
file.setSize(nextInt);
break;
}
default: {
jsonReader.skipValue();
}
}
}
fileList.add(file.build());
jsonReader.endObject();
}
jsonReader.endObject();
return fileList;
}
}
然后只需用@GsonTypeAdapter
inside注释 files 字段GistResponse.java
。
@AutoValue
public abstract class GistResponse {
@SerializedName("id")
public abstract String getId();
@GsonTypeAdapter(FileTypeAdapter.class)
@SerializedName("files")
public abstract FileName getFileNameList();
public static Builder builder() {
return new AutoValue_GistResponse.Builder();
}
@AutoValue.Builder
public abstract static class Builder {
public abstract Builder setId(String value);
public abstract Builder setFileNameList(FileName value);
public abstract GistResponse build();
}
public static TypeAdapter<GistResponse> typeAdapter(Gson gson) {
return new AutoValue_GistResponse.GsonTypeAdapter(gson);
}
}
现在可以解析它了。