Get JSON from EXE over stdout

[Alex Serbia]

Hi all,

I'm new win Java and I have small problem to get bytes via stdout, and from them create JSON.

Sensor simulator file is .EXE ( https://drive.google.com/open?id=1WZj6vmAfzFysCRUYgymqqueh-wt-1cue )

Problem is next:
The simulator can be spawned with a --name argument. If no name is given, a random name will be generated.
I can have a few .EXE files and over stdout and mapping bytes I need to write JSON in log file.

JSON should have this format:

{
"timestamp": "2008-09-15T15:53:00+05:00",
"name": "sensor1",
"temperature": 273.15
"humidity": 99.1
}

Sensor data format
The sensor data is a binary format. Each reading will be packaged with the length of the packet, a
timestamp, a name of the sensor, and the available sensor readings. Strings are in UTF-8. Numerical
values are in network byte order.

Offset	Field name	Type	Size	Description
0	plength	unsigned integer	4 bytes	The length of package, including this field
4	timestamp	unsigned integer	8 bytes	Unix timestamp, in milliseconds
12	nlen	unsigned integer	1 byte	The length of the name
13	name	string	nlen bytes	The length of the name
13 + nlen	temperature	unsigned integer	3 bytes	In hundredths of K
16 + nlen (13 +nlen)	humidity	unsigned integer	2 bytes	Relative humidity in ‰

Note: Both temperature and humidity are optional. This means that the offset for humidity can
also be 13 + nlen.


I did something like this, but I don't think that I'm on the good way:

Process process = Runtime.getRuntime().exec("C:\\resources\\sensor_simulator_01.exe");
InputStream stdin = process.getInputStream();
OutputStream stdout = process.getOutputStream();
???

I need this ASAP, so please help me to solve, also to understand

Thank you!

[Paul Clapham]

No, if you don't have to use Runtime.exec() then I strongly recommend not to use it.

Why can't you just run your sensor-simulator at the command line and pipe the output into this Java program you want to write? Something like:

cd \resources
sensor_simulator_01.exe | java ConvertSensorDataToJson

[Alex Serbia]

Paul Clapham wrote:No, if you don't have to use Runtime.exec() then I strongly recommend not to use it.

Why can't you just run your sensor-simulator at the command line and pipe the output into this Java program you want to write? Something like:

cd \resources
sensor_simulator_01.exe | java ConvertSensorDataToJson

Thank you on your answer, but I'm not familiar with this command type... :(

Questions:
1) ConvertSensorDataToJson - this is Main class?
2) "sensor_simulator_01.exe | java ConvertSensorDataToJson" or "java ConvertSensorDataToJson | sensor_simulator_01"?

Can someone provide me a some code? To learn on first place...than to solve my task for school.

[Paul Clapham]

Alex Serbia wrote:1) ConvertSensorDataToJson - this is Main class?

Yes, it's the class you're going to write to convert the sensor data to Json.

2) "sensor_simulator_01.exe | java ConvertSensorDataToJson" or "java ConvertSensorDataToJson | sensor_simulator_01"?

Yes, the pipes work from left to right. Example tutorial: Command Redirection, Pipes.

Can someone provide me a some code? To learn on first place...than to solve my task for school.

I don't know what you have in mind  Nobody here is going to write your code for you. But if you like, you could start working on it and ask questions when you get stuck.