public static String toJson(
Object target,
Type targetType,
boolean isSerializeNulls,
Double version,
String datePattern,
boolean excludesFieldsWithoutExpose) {
if (target == null) return EMPTY_JSON;
GsonBuilder builder = new GsonBuilder();
if (isSerializeNulls) builder.serializeNulls();
if (version != null) builder.setVersion(version.doubleValue());
if (TextUtils.isEmpty(datePattern)) datePattern = DEFAULT_DATE_PATTERN;
builder.setDateFormat(datePattern);
if (excludesFieldsWithoutExpose) builder.excludeFieldsWithoutExposeAnnotation();
String result = EMPTY;
Gson gson = builder.create();
try {
if (targetType != null) {
result = gson.toJson(target, targetType);
} else {
result = gson.toJson(target);
}
} catch (Exception ex) {
if (target instanceof Collection
|| target instanceof Iterator
|| target instanceof Enumeration
|| target.getClass().isArray()) {
result = EMPTY_JSON_ARRAY;
} else result = EMPTY_JSON;
}
return result;
}
static {
// Initialize httpclient
HttpParams params = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(params, HTTP_CONNECTION_TIMEOUT);
ThreadSafeClientConnManager connectionManager = new ThreadSafeClientConnManager();
connectionManager.setMaxTotal(HTTP_MAX_CONNECTIONS);
connectionManager.setDefaultMaxPerRoute(HTTP_MAX_CONNECTIONS_PER_ROUTE);
httpClient = new ContentEncodingHttpClient(connectionManager, params);
// Initialize GSON
GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.registerTypeAdapter(ImageImpl.class, new MovieImageDeserializer());
gsonBuilder.serializeNulls();
gson = gsonBuilder.create();
}
static {
gsonBuilder = new GsonBuilder();
gsonBuilder.serializeNulls();
gsonBuilder.setDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ");
}
/**
* @author Roger.xia
* <p>We use this class to convert Object to JSON string and reverse.
* <p>This implementation is currently based on GSON.
*/
public class JSONUtil {
private static final Logger logger = Logger.getLogger("JSONUtil.class");
public static final String EMPTY_JSON = "{}";
public static final String EMPTY_JSON_ARRAY = "[]";
private JSONUtil() {}
private static final GsonBuilder builder = new GsonBuilder();
private static final Gson gson = builder.serializeNulls().create();
/**
* by default,this method allows serialize null-value properties
*
* @param src
* @return
*/
public static String toJson(Object src) {
if (src == null) {
return EMPTY_JSON;
}
return gson.toJson(src);
}
/**
* default is medium : Mar 8, 2013 12:00:00 AM
*
* @param obj
* @param dateFormat Note that this pattern must abide by the convention provided by
* SimpleDateFormat class.
* @return
*/
public static String toJson(Object obj, String dateFormat) {
if (obj == null) {
return EMPTY_JSON;
} else if (StringUtils.isBlank(dateFormat)) {
return gson.toJson(obj);
}
try {
return builder.setDateFormat(dateFormat).create().toJson(obj);
} catch (Exception e) {
logger.error("Exception for toJson(obj, dateFormat) : " + e.getMessage());
return gson.toJson(obj);
}
}
public static String toJson(Object target, Type targetType) {
String result = EMPTY_JSON;
if (target == null) return result;
try {
if (targetType != null) {
result = gson.toJson(target, targetType);
} else {
result = gson.toJson(target);
}
} catch (Exception ex) {
logger.error(
"JSONUtil.toJson(target, targetType) exception, return empty json, exception for "
+ target.toString()
+ " : "
+ ex.getMessage());
if (target instanceof Collection
|| target instanceof Iterator
|| target instanceof Enumeration
|| target.getClass().isArray()) {
result = EMPTY_JSON_ARRAY;
} else result = EMPTY_JSON;
}
return result;
}
/**
* to covert a string to a class
*
* @param json
* @param classOfT
* @return
*/
public static <T> T fromJson(String json, Class<T> classOfT) {
return gson.fromJson(json, classOfT);
}
public static <T> T fromJson(String json, Type type) {
return gson.fromJson(json, type);
}
/**
* to covert a JsonElement to a class
*
* @param json
* @param classOfT
* @return
*/
public static <T> T fromJson(JsonElement jsonElem, Class<T> classOfT) {
return gson.fromJson(jsonElem, classOfT);
}
/**
* convert json string to list
*
* @param jsonStr
* @param type
* @return
*/
public static List<?> jsonToList(String json, Type type) {
List<?> objList = gson.fromJson(json, type);
return objList;
}
/**
* convert json to map
*
* @param jsonStr
* @return
*/
public static Map<?, ?> jsonToMap(String json) {
Type type = new TypeToken<Map<?, ?>>() {}.getType();
Map<?, ?> objMap = gson.fromJson(json, type);
return objMap;
}
public static void main(String[] args) {
Map<String, Object> obj = new HashMap<String, Object>();
obj.put("k1", "k1v");
obj.put("k2", 2);
try {
obj.put("k3", DateUtil.parseDate("03/08/2013"));
} catch (ParseException e) {
e.printStackTrace();
}
System.out.println(JSONUtil.toJson(obj));
System.out.println(JSONUtil.toJson(obj, "yyyy-MM-dd"));
System.out.println(JSONUtil.toJson(obj));
}
}