Nexus2: How can I get a list of all artifacts from a specific repository via REST API?
Try this: 

# Get status
curl http://localhost:8081/nexus/service/local/status 
# List of repositories
curl http://localhost:8081/nexus/service/local/repositories


For the json parameter: 

curl -i -H "Accept: application/json" &lt;url&gt;


More information, see this link