RESTful Web Services (JAX-RS) @QueryParam Example

• Introduction to web services
• Web services interview questions
• SOAP web service introduction
• RESTful web service introduction
• Difference between SOAP and REST web services
• SOAP web service example in java using eclipse
• JAX-WS web service eclipse tutorial
• JAX-WS web service deployment on tomcat
• Create RESTful web service in java(JAX-RS) using jersey
• RESTful web service
• JAXRS json example using jersey
• RESTful web service
• JAXRS CRUD example using jersey
• AngularJS RESTful web service
• JAXRS CRUD example using $http
• RESTful Web Services (JAX-RS) @QueryParam Example
• Spring Rest simple example
• Spring Rest json example
• Spring Rest xml example
• Spring Rest CRUD example

In previous post, we have used @PathParam for passing parameter to URL in RESTful Web Services json example and we have directly passed parameter values but JAXRS @QueryParam can be used to pass query parameters. In case of @QueryParam, we pass parameters as well as its values.
For example: http://localhost:8080/JAXRSJsonExample/rest/countries/country?id=3&countryName=Nepal
Here Parameter names are id,countryName and its values are 3,Nepal respectively.

http://localhost:8080/JAXRSJsonExample/rest/listOfCustomers?start=10&size=10

Here are steps to create a JAXRS json example which will use @QueryParam.

1) Follow steps on RESTful Web Services json example to create simple RESTful web services which uses @PathParam.
2) Change CountryRestService.java to use @QueryParam as below.

package org.arpit.java2blog.jaxrs; import java.util.ArrayList; import java.util.List; import javax.ws.rs.GET; import javax.ws.rs.Path; import javax.ws.rs.Produces; import javax.ws.rs.QueryParam; import javax.ws.rs.core.MediaType; import org.arpit.java2blog.bean.Country; /* * author: Arpit Mandliya * */ @Path("/countries") public class CountryRestService { @GET @Produces(MediaType.APPLICATION_JSON) public List<Country> getCountries() { List<Country> listOfCountries = new ArrayList<Country>(); listOfCountries=createCountryList(); return listOfCountries; } @GET @Path("/country") @Produces(MediaType.APPLICATION_JSON) public Country getCountryById(@QueryParam("id") int id,@QueryParam("countryName") String countryName) { List<Country> listOfCountries = new ArrayList<Country>(); listOfCountries=createCountryList(); for (Country country: listOfCountries) { if(country.getId()==id && country.getCountryName().equalsIgnoreCase(countryName)) return country; } return null; } // Utiliy method to create country list. public List<Country> createCountryList() { Country indiaCountry=new Country(1, "India"); Country chinaCountry=new Country(4, "China"); Country nepalCountry=new Country(3, "Nepal"); Country bhutanCountry=new Country(2, "Bhutan"); List<Country> listOfCountries = new ArrayList<Country>(); listOfCountries.add(indiaCountry); listOfCountries.add(chinaCountry); listOfCountries.add(nepalCountry); listOfCountries.add(bhutanCountry); return listOfCountries; } }

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package org.arpit.java2blog.jaxrs;   import java.util.ArrayList; import java.util.List;   import javax.ws.rs.GET; import javax.ws.rs.Path; import javax.ws.rs.Produces; import javax.ws.rs.QueryParam; import javax.ws.rs.core.MediaType;   import org.arpit.java2blog.bean.Country; /* * author: Arpit Mandliya * */ @Path("/countries") public class CountryRestService {   @GET @Produces(MediaType.APPLICATION_JSON) public List<Country> getCountries() { List<Country> listOfCountries = new ArrayList<Country>(); listOfCountries=createCountryList(); return listOfCountries; }   @GET @Path("/country") @Produces(MediaType.APPLICATION_JSON) public Country getCountryById(@QueryParam("id") int id,@QueryParam("countryName") String countryName) { List<Country> listOfCountries = new ArrayList<Country>(); listOfCountries=createCountryList();   for (Country country: listOfCountries) { if(country.getId()==id && country.getCountryName().equalsIgnoreCase(countryName)) return country; }   return null; }   // Utiliy method to create country list. public List<Country> createCountryList() { Country indiaCountry=new Country(1, "India"); Country chinaCountry=new Country(4, "China"); Country nepalCountry=new Country(3, "Nepal"); Country bhutanCountry=new Country(2, "Bhutan");   List<Country> listOfCountries = new ArrayList<Country>(); listOfCountries.add(indiaCountry); listOfCountries.add(chinaCountry); listOfCountries.add(nepalCountry); listOfCountries.add(bhutanCountry); return listOfCountries; } }

That’s all. We need to run the application now.

Run the application

3) Right click on project -> run as -> run on server

Select apache tomcat and click on finish

4) Now pass country id and country name as parameter to url.

“http://localhost:8080/JAXRSJsonExample/rest/countries/country?id=3&countryName=Nepal”.

We are done with Restful web services json QueryParam example. If you are still facing any issue, please comment.