How to parse request parameter (query and path param) and request body in same POJO in REST API

Question

How to parse request parameter (query and path param) and request body in same POJO in REST API

1.4k views Asked by pjain At 18 September 2018 at 20:39

I have a rest API (PUT verb) which accepts both request body and path params:

Ex:

curl --data {a:1, b:2} -X PUT "https://example.com/users/{username}/address/{addressname}"

I am trying to fetch both request body and path param in one POJO

Response myAPI(@BeanParam Users user){
   system.out.println(user.username);
   system.out.println(user.a);

Users class

public class Users{

    @PathParam(username)
    private String userName;
    ......

    private String a;
  ......
}

But I am getting value of user.a as null. How to parse both request body and param in same class?

Original Q&A

There are 1 answers

**Paul Samsotha** · Answer 1 · 2018-09-24T09:55:14+00:00

You can do this with a custom annotation and an InjectionResolver. What the InjectionResolver does is allow you to create a custom injection point with your own annotation. So you could do something like

public class Users {

    @PathParam(username)
    private String userName;

    @Body
    private String a;
}

When implementing the InjectionResolver, you would grab the actual body from the ContainerRequest using the ContainerRequest#readEntity(Class) method. You would determine the Class to pass by doing some reflection on the Field that you can obtain inside the InjectionResolver. Below is a complete example using Jersey Test Framework. Run it like any other JUnit test.

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Field;

import javax.inject.Inject;
import javax.inject.Singleton;
import javax.ws.rs.BeanParam;
import javax.ws.rs.Consumes;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.client.Entity;
import javax.ws.rs.core.Response;

import org.glassfish.hk2.api.Injectee;
import org.glassfish.hk2.api.InjectionResolver;
import org.glassfish.hk2.api.ServiceHandle;
import org.glassfish.hk2.api.TypeLiteral;
import org.glassfish.hk2.utilities.binding.AbstractBinder;
import org.glassfish.jersey.server.ContainerRequest;
import org.glassfish.jersey.server.ResourceConfig;
import org.glassfish.jersey.test.JerseyTest;
import org.junit.Test;

/**
 * Only one required dependency to run this test. Note this is using 2.25.1.
 * If you are using 2.26 or later, the implementation will be different,
 * and this will not work. You need to use the Jersey packaged `InjectionResolver`,
 * not the HK2 one. And you will also need to bind that `InjectionResolver`
 * to `GenericType` instead of `TypeLiteral` in the `AbstractBinder#configure()`.
 *
 * <dependency>
 *   <groupId>org.glassfish.jersey.test-framework.providers</groupId>
 *   <artifactId>jersey-test-framework-provider-grizzly2</artifactId>
 *   <version>2.25.1</version>
 *   <scope>test</scope>
 * </dependency>
 */
public class BeanParamTest extends JerseyTest {

    @Path("test")
    @Consumes("application/json")
    @Produces("application/json")
    public static class TestResource {

        @POST
        @Path("{username}")
        public String post(@BeanParam ModelBean bean) {
            return bean.toString();
        }
    }

    @Override
    public ResourceConfig configure() {
        return new ResourceConfig(TestResource.class)
                .register(new AbstractBinder() {
                    @Override
                    protected void configure() {
                        bind(BodyInjectionResolver.class)
                                .to(new TypeLiteral<InjectionResolver<Body>>() {})
                                .in(Singleton.class);
                    }
                });
    }

    @Test
    public void testIt() {
        final Response res = target("test/peeskillet")
                .request()
                .post(Entity.json("{\"foo\":\"bar\"}"));
        System.out.println(res.readEntity(String.class));
    }

    @Retention(RetentionPolicy.RUNTIME)
    @Target({ElementType.FIELD})
    public @interface Body {}

    public static class ModelBean {

        @PathParam("username")
        private String username;

        @Body
        private String body;

        public String getUsername() {
            return username;
        }

        public void setUsername(String username) {
            this.username = username;
        }

        public String getBody() {
            return body;
        }

        public void setBody(String body) {
            this.body = body;
        }

        @Override
        public String toString() {
            return "ModelBean{" +
                    "username='" + username + '\'' +
                    ", body='" + body + '\'' +
                    '}';
        }
    }

    public static class BodyInjectionResolver implements InjectionResolver<Body> {

        @Inject
        private javax.inject.Provider<ContainerRequest> requestProvider;

        @Override
        public Object resolve(Injectee injectee, ServiceHandle<?> serviceHandle) {
            if (injectee.getParent().isAnnotationPresent(Body.class)) {
                AnnotatedElement parent = injectee.getParent();
                if (parent instanceof Field) {
                    Class<?> entityType = ((Field) parent).getType();
                    return requestProvider.get().readEntity(entityType);
                }

            }
            return null;
        }

        @Override
        public boolean isConstructorParameterIndicator() {
            return false;
        }

        @Override
        public boolean isMethodParameterIndicator() {
            return false;
        }
    }
}

TechQA.

How to parse request parameter (query and path param) and request body in same POJO in REST API

There are 1 answers

Related Questions in JAVA

Related Questions in REST

Related Questions in JERSEY

Related Questions in PUT

Related Questions in PATH-PARAMETER

Popular Questions

Popular Tags

Trending Questions