Java 如何使用GSON反序列化不同对象的数组
我收到这样的JSONJava 如何使用GSON反序列化不同对象的数组,java,json,gson,Java,Json,Gson,我收到这样的JSON [ { "albums" : [ {"id":"0", "name":"name"}, {"id":"1", "name":"name"} ], "name":"name" }, { "tracks" : [ {"id":"0", "name":"name", "duration":"3:30"}, {"id":"1", "name":"name", "duration":"2:40
[
{
"albums" : [
{"id":"0", "name":"name"},
{"id":"1", "name":"name"}
],
"name":"name"
},
{
"tracks" : [
{"id":"0", "name":"name", "duration":"3:30"},
{"id":"1", "name":"name", "duration":"2:40"}
],
"name":"name"
},
{
"playlists" : [
{"id":"0", "name":"name", "tracksCount":"3"},
{"id":"1", "name":"name", "tracksCount":"40"}
],
"name":"name"
}
]
Tracks {
String name;
List<Track> tracks;
}
Albums {
String name;
List<Album> albums;
}
Playlists {
String name;
List<Playlist> playlists;
}
class JsonResponse {
Albums albums;
Tracks tracks;
Playlists playlists;
}
[
{
"albums" : [
{"id":"0", "name":"name"},
{"id":"1", "name":"name"}
],
"name":"name"
}
]
顺便说一句，我不能更改JSON。因此，我需要一个代码来解析它。您发布的JSON没有显示JSONResponse对象数组，而是包含Albums、Tracks和Playlists类型的JSON对象。如果换成这样，情况会有所不同：
[
{
{
"albums" : [
{"id":"0", "name":"name"},
{"id":"1", "name":"name"}
],
"name":"name"
},
{
"tracks" : [
{"id":"0", "name":"name", "duration":"3:30"},
{"id":"1", "name":"name", "duration":"2:40"}
],
"name":"name"
},
{
"playlists" : [
{"id":"0", "name":"name", "tracksCount":"3"},
{"id":"1", "name":"name", "tracksCount":"40"}
],
"name":"name"
}
}
]
[
{
"albums" : [
{"id":"0", "name":"name"},
{"id":"1", "name":"name"}
],
"name":"name"
},
{
"tracks" : [
{"id":"0", "name":"name", "duration":"3:30"},
{"id":"1", "name":"name", "duration":"2:40"}
],
"name":"name"
},
{
"playlists" : [
{"id":"0", "name":"name", "tracksCount":"3"},
{"id":"1", "name":"name", "tracksCount":"40"}
],
"name":"name"
}
]
String json = "[{\"albums\":[{\"id\":\"0\",\"name\":\"name\"},{\"id\":\"1\",\"name\":\"name\"}],\"name\":\"name\"},{\"tracks\":[{\"id\":\"0\",\"name\":\"name\",\"duration\":\"3:30\"},{\"id\":\"1\",\"name\":\"name\",\"duration\":\"2:40\"}],\"name\":\"name\"},{\"playlists\":[{\"id\":\"0\",\"name\":\"name\",\"tracksCount\":\"3\"},{\"id\":\"1\",\"name\":\"name\",\"tracksCount\":\"40\"}],\"name\":\"name\"}]";
class JsonResponse {
ArrayList<Album> albums;
ArrayList<Track> tracks;
ArrayList<Playlist> playlists;
String name;
@Override
public String toString() {
return "JsonResponse [albums=" + albums + ", tracks=" + tracks
+ ", playlists=" + playlists + ", name=" + name + "]";
}
}
class Track{
int id;
String name;
String duration;
@Override
public String toString() {
return "Track [id=" + id + ", name=" + name + ", duration=" + duration
+ "]";
}
}
class Album{
int id;
String name;
@Override
public String toString() {
return "Album [id=" + id + ", name=" + name + "]";
}
}
class Playlist{
int id;
String name;
int tracksCount;
@Override
public String toString() {
return "Playlist [id=" + id + ", name=" + name + ", tracksCount="
+ tracksCount + "]";
}
}
实际上，您在JsonResponse类中犯了错误 它明确表示json格式是从数组开始的，在JsonResponse类中，您只需编写单个对象，而不是对象的集合。如果您仔细查看Gson异常 “
BEGIN\u对象，但它是BEGIN\u数组private List<Albums> albums;
private List<Tracks> tracks;
private List<Playlists> playlists;
私人列表相册；
私有列表轨道；
私人列表播放列表；
谢谢大家的帮助！这是我的解决办法
public class JsonResponse {
public static class Item {
String name;
}
public static class Tracks extends Item {
List<Track> tracks;
}
public static class Albums extends Item {
List<Album> albums;
}
public static class Playlists extends Item {
List<Playlist> playlists;
}
public static class JsonResponseDeserialize implements JsonDeserializer<List<? extends Item>> {
Gson gson = new Gson();
@Override
public List<? extends Item> deserialize(JsonElement el, Type type, JsonDeserializationContext context) throws JsonParseException {
List<Item> ls = new ArrayList<Item>();
JsonArray jarr = el.getAsJsonArray();
for (JsonElement e : jarr) {
Item i;
if (e.getAsJsonObject().get("tracks") != null){
i = gson.lsomJson(e, Tracks.class);
if (i != null) {
ls.add(i);
continue;
}
}
if (e.getAsJsonObject().get("albums") != null){
i = gson.lsomJson(e, Albums.class);
if (i != null) {
ls.add(i);
continue;
}
}
if (e.getAsJsonObject().get("playlists") != null){
i = gson.lsomJson(e, Playlists.class);
if (i != null) {
ls.add(i);
continue;
}
}
}
return ls;
}
}
private Tracks _tracks;
private Albums _albums;
private Playlists _playlists;
}
公共类JsonResponse{
公共静态类项{
字符串名；
}
公共静态类跟踪扩展项{
列出曲目；
}
公共静态类相册扩展项{
列出相册；
}
公共静态类播放列表扩展项{
列出播放列表；
}
公共静态类JsonResponseDeserialize实现JsonDeserializer最近我出于同样的目的使用了RuntimeTypeAdapterFactory，这是一个简单的解决方案。它是一个开放的Gson集成（额外）
查看此帖子以查看和激活示例
我将原始代码从github直接导入到我的项目中（因为该类不直接拥有maven依赖项）：
代码
希望有助于我无法更改JSON。因此我需要一个代码来解析它。我知道JSON结构不在您的控制之下，但您误解了您所拥有的：您没有JSONResponse对象数组，而是播放列表、曲目等的数组……所以，没问题，您只需要实现自己的反序列化程序；下面是一个示例我无法更改JSON。因此我需要一个代码来解析它。希望您有Album、Track&Playlist类，只需更改JsonResponse，您的方法是正确的，只是JsonResponse类中有一个小错误。JsonResponse类包含对象，但不包含列表/数组，因为列表/数组旁边有一个字符串字段“name”。
public class JsonResponse {
public static class Item {
String name;
}
public static class Tracks extends Item {
List<Track> tracks;
}
public static class Albums extends Item {
List<Album> albums;
}
public static class Playlists extends Item {
List<Playlist> playlists;
}
public static class JsonResponseDeserialize implements JsonDeserializer<List<? extends Item>> {
Gson gson = new Gson();
@Override
public List<? extends Item> deserialize(JsonElement el, Type type, JsonDeserializationContext context) throws JsonParseException {
List<Item> ls = new ArrayList<Item>();
JsonArray jarr = el.getAsJsonArray();
for (JsonElement e : jarr) {
Item i;
if (e.getAsJsonObject().get("tracks") != null){
i = gson.lsomJson(e, Tracks.class);
if (i != null) {
ls.add(i);
continue;
}
}
if (e.getAsJsonObject().get("albums") != null){
i = gson.lsomJson(e, Albums.class);
if (i != null) {
ls.add(i);
continue;
}
}
if (e.getAsJsonObject().get("playlists") != null){
i = gson.lsomJson(e, Playlists.class);
if (i != null) {
ls.add(i);
continue;
}
}
}
return ls;
}
}
private Tracks _tracks;
private Albums _albums;
private Playlists _playlists;
}
private static List<? extends Item> getDatalsomJson(String jsonString) {
Type type = new TypeToken<List<? extends JsonResponse.Item>>(){}.getType();
GsonBuilder gb = new GsonBuilder();
gb.registerTypeAdapter(type, new JsonResponse.JsonResponseDeserialize());
Gson gson = gb.create();
List<? extends Item> ls = gson.lsomJson(jsonString, type);
return ls;
}