https://www.ngdata.com/parsing-a-large-json-file-efficiently-and-easily/
https://sites.google.com/site/gson/streaming
http://www.acuriousanimal.com/2015/10/23/reading-json-file-in-stream-mode-with-gson.html
public static void main(String [] args) throws IOException {
String filePath = "C:big-data.json";
FileInputStream in = new FileInputStream(new File(filePath));
JsonReader reader = new JsonReader(new InputStreamReader(in, "UTF-8"));
Gson gson = new GsonBuilder().create();
// reader.beginObject();
// reader.nextName();
reader.beginObject();//跳過"{"
while (reader.hasNext()) {
// Read data into object model
JsonToken jsonToken = reader.peek();
if(jsonToken.equals(JsonToken.NAME)) {
String name = reader.nextName();
if(name.equalsIgnoreCase("SUMMARY")) {
// reader.beginObject();
Summary summary = gson.fromJson(reader, Summary.class);
logger.info(summary.toString());
break;
// reader.endObject();//跳過"}"
}
} /*else if(jsonToken.equals(JsonToken.BEGIN_OBJECT)) {
reader.beginObject();
} else if(jsonToken.equals(JsonToken.STRING)) {
logger.info(reader.nextString());
} else if(jsonToken.equals(JsonToken.NUMBER)) {
logger.info(reader.nextInt() + "");
} else if(jsonToken.equals(JsonToken.END_OBJECT)) {
reader.endObject();
} */
// Summary summary = gson.fromJson(reader, Summary.class);
// break;
}
reader.close();
}