java pojo to json

jp2j.java

	// convert json string into pojo
	public static Object getAsObject(String json, Class<?> objClass) throws Exception {
		JsonParser jParser = new JsonParser();
		JsonObject jObj = (JsonObject) jParser.parse(json);
		Object obj = objClass.getDeclaredConstructor().newInstance();
		Field[] fields = objClass.getDeclaredFields();

		for (int i = 0; i < fields.length; i++) {
			String fieldName = fields[i].getName();
			Field field = obj.getClass().getDeclaredField(fieldName);
			field.setAccessible(true);
			Class<?> fieldType = fields[i].getType();

			String fieldTypeName = fieldType.getName();
			if(fieldTypeName.equals("java.lang.String")){
				try {
					String value = jObj.get(fieldName).getAsString();	
					field.set(obj, value);
				}catch (Exception e) {}
			}else if(fieldTypeName.equals("java.lang.Integer")||fieldTypeName.equals("int")){
				try {
					int value = jObj.get(fieldName).getAsInt();
					field.set(obj, value);					
				}catch (Exception e) {}
			}else if(fieldTypeName.equals("long")){
				try {
					long value = jObj.get(fieldName).getAsLong();
					field.set(obj, value);					
				}catch (Exception e) {}
			}else {
				throw new Exception("Field Value is not string, int or long but "+fieldTypeName);
			}
		}
		return obj;
	}

	// convert arraylist of pojos to json array
	public static String getAsJSON(ArrayList<?> list) throws IllegalArgumentException, IllegalAccessException {
		String json = "[";
		for (Object object : list) {
			json += JSONRef.getAsJSON(object) + ",";
		}
		json = json.length()>1?json.substring(0, json.length() - 1) : json;
		return json + "]";
	}

	// convert pojo to json object
	public static String getAsJSON(Object obj, boolean surpressObjCurlies) throws IllegalArgumentException, IllegalAccessException {
		Class<? extends Object> objClass = obj.getClass();
		Field[] fields = objClass.getDeclaredFields();
		String json = surpressObjCurlies?"":"{";
		for (int i = 0; i < fields.length; i++) {
			String name = fields[i].getName();
			fields[i].setAccessible(true);
			Object value = fields[i].get(obj);
			if (value instanceof String) {
				json += "\"" + name + "\":\"" + value + "\",";
			}else if(value instanceof ArrayList<?>) {
				json += "\"" + name + "\": ["; 
				@SuppressWarnings("unchecked")
				ArrayList<Object> arrList = (ArrayList<Object>) value;
				for (Object arrListObj : arrList) {
					if(arrListObj instanceof String) {
						json += "\""+(String)arrListObj+"\",";
					}else {
						json += (String)arrListObj+",";
					}
				}
				json = removeTrailingComma(json);
				json += "]";
			} else {
				json += "\"" + name + "\":" + value + ",";
			}
		}
		json = removeTrailingComma(json);
		return json + (surpressObjCurlies?"":"}");
	}

	private static String removeTrailingComma(String json) {
		json = json.endsWith(",")?json.substring(0, json.length() - 1) : json;
		return json;
	}

	// convert resultset to json
	public static String getAsJSONFromRS(ResultSet rs) throws SQLException {
		String json = "[";
		
		ResultSetMetaData rsmd = rs.getMetaData();
		int columnCount = rsmd.getColumnCount();
		
		while (rs.next()) {
			json+="{";
			for (int i = 1; i <= columnCount; i++ ) {
			  String name = rsmd.getColumnName(i);
			  String value = rs.getString(name);
			  value = value==null?"null":value;
			  value = value.replaceAll("\r", "").replaceAll("\n", "\\\\n");
			  if(requiresQuotes(rsmd.getColumnType(i))) {
				  json+="\""+name+"\":\""+value+"\",";
			  }else {
				  json+="\""+name+"\":"+value+",";				  
			  }
			}
			json+="},";
			json = json.substring(0, json.length() - 1);
		}
		json = json.length()>1?json.substring(0, json.length() - 1) : json;
		return json + "]";
	}

	private static boolean requiresQuotes(int i) throws SQLException {
		boolean requires = true;
		if(i == java.sql.Types.INTEGER) {
			requires=false;
		}
		if(i == java.sql.Types.BOOLEAN) {
			requires=false;
		}
		if(i == java.sql.Types.BIGINT) {
			requires=false;
		}
		if(i == java.sql.Types.BIT) {
			requires=false;
		}
		if(i == java.sql.Types.DECIMAL) {
			requires=false;
		}
		if(i == java.sql.Types.DOUBLE) {
			requires=false;
		}
		if(i == java.sql.Types.FLOAT) {
			requires=false;
		}
		if(i == java.sql.Types.DOUBLE) {
			requires=false;
		}
		if(i == java.sql.Types.TINYINT) {
			requires=false;
		}
		System.out.println(i+" REQ - "+requires);
		return requires;
	}

	// convert result set to typed object list
	public static <T> ArrayList<T> createFromRS(ResultSet s, Class<T> objClass) throws Exception {
		T obj = objClass.getDeclaredConstructor().newInstance();
		ArrayList<T> objs = new ArrayList<T>();
		Field[] fields = objClass.getDeclaredFields();
		
		while (s.next()) {
        		obj = objClass.getDeclaredConstructor().newInstance();
			for (int i = 0; i < fields.length; i++) {
				String fieldName = fields[i].getName();
				Field field = obj.getClass().getDeclaredField(fieldName);
				field.setAccessible(true);
				Class<?> fieldType = fields[i].getType();
	
				String fieldTypeName = fieldType.getName();
				if(fieldTypeName.equals("java.lang.String")){
					try {
						String value = s.getString(fieldName);
						field.set(obj, value);
					}catch (Exception e) { throw new Exception(e); }
				}else if(fieldTypeName.equals("java.lang.Integer")||fieldTypeName.equals("int")){
					try {
						int value = s.getInt(fieldName);
						field.set(obj, value);					
					}catch (Exception e) { throw new Exception(e); }
				}else if(fieldTypeName.equals("long")){
					try { 
						long value = s.getLong(fieldName);
						field.set(obj, value);					
					}catch (Exception e) { throw new Exception(e); }
				}else {
					throw new Exception("Field Value is not string, int or long but "+fieldTypeName);
				}
			}
			objs.add((T) obj);
        }
        return objs;
	}