How do I POST JSON data with cURL?

Try to put your data in a file, say body.json and then use

curl -H "Content-Type: application/json" --data @body.json http://localhost:8080/ui/webapp/conf

You need to set your content-type to application/json. But -d (or --data) sends the Content-Type application/x-www-form-urlencoded, which is not accepted on Spring's side.

Looking at the curl man page, I think you can use -H (or --header):

-H "Content-Type: application/json"

Full example:

curl --header "Content-Type: application/json" \
  --request POST \
  --data '{"username":"xyz","password":"xyz"}' \
  http://localhost:3000/api/login

(-H is short for --header, -d for --data)

Note that -request POST is optional if you use -d, as the -d flag implies a POST request.

---

On Windows, things are slightly different. See the comment thread.

For Windows, having a single quote for the -d value did not work for me, but it did work after changing to double quote. Also I needed to escape double quotes inside curly brackets.

That is, the following did not work:

curl -i -X POST -H "Content-Type: application/json" -d '{"key":"val"}' http://localhost:8080/appname/path

But the following worked:

curl -i -X POST -H "Content-Type: application/json" -d "{\"key\":\"val\"}" http://localhost:8080/appname/path

You might find resty useful: https://github.com/micha/resty

It's a wrapper round CURL which simplifies command line REST requests. You point it to your API endpoint, and it gives you PUT and POST commands. (Examples adapted from the homepage)

$ resty http://127.0.0.1:8080/data #Sets up resty to point at your endpoing
$ GET /blogs.json                  #Gets http://127.0.0.1:8080/data/blogs.json
                                   #Put JSON
$ PUT /blogs/2.json '{"id" : 2, "title" : "updated post", "body" : "This is the new."}'
                                   # POST JSON from a file
$ POST /blogs/5.json < /tmp/blog.json

Also, it's often still necessary to add the Content Type headers. You can do this once, though, to set a default, of add config files per-method per-site: Setting default RESTY options