JSON-RPC for Java with Spring

1. Add Dependency

We use the jsonrpc4j library, the latest version is 1.5.3 https://github.com/briandilley/jsonrpc4j

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<dependency>     <groupid>com.github.briandilley.jsonrpc4j</groupId>     <artifactid>jsonrpc4j</artifactId>     <version>1.5.3</version> </dependency>

2. Create AutoJsonRpcServiceImplExporter

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import com.googlecode.jsonrpc4j.spring.AutoJsonRpcServiceImplExporter; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration;   @Configuration public class ApplicationConfig {       @Bean     public static AutoJsonRpcServiceImplExporter autoJsonRpcServiceImplExporter() {         AutoJsonRpcServiceImplExporter exp = new AutoJsonRpcServiceImplExporter();         //in here you can provide custom HTTP status code providers etc. eg:         //exp.setHttpStatusCodeProvider();         //exp.setErrorResolver();         return exp;     } }

3. Create ServerAPI interface

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import com.googlecode.jsonrpc4j.JsonRpcParam; import com.googlecode.jsonrpc4j.JsonRpcService; import java.util.List;   @JsonRpcService("/api") public interface ServerAPI {       long multiplier(@JsonRpcParam(value = "a") long a, @JsonRpcParam(value = "b") long b);       String printPerson(@JsonRpcParam(value = "person") Person person);           String printPersons(@JsonRpcParam(value = "persons") List<person> persons); }

4. Create ServerAPI implementation

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import com.googlecode.jsonrpc4j.spring.AutoJsonRpcServiceImpl; import java.util.List; import org.springframework.stereotype.Service;   @Service @AutoJsonRpcServiceImpl public class ServerAPIImpl implements ServerAPI {       @Override     public long multiplier(long a, long b) {         return a * b;     }       @Override     public String printPerson(Person person) {         return person.toString();     }      @Override     public String printPersons(List<person> persons) {         return persons.toString();     } }

5. Deploy to glassfish server

6. Use Postman to test API

6.1. Test 'multiplier' method

Send POST request with 'application/json' to endpoint 'http://localhost:8080/jsonrpc4j/api'

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1	{"id":"1","jsonrpc":"2.0","method":"multiplier","params":{"a":1111111,"b":11111}}

6.2. Test 'printPerson' method

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1	{"id":"1","jsonrpc":"2.0","method":"printPerson","params":{"person":{"name":"Solar City","yearOfBirth":2000}}}

6.3. Test 'printPersons' method

Send POST request with 'application/json' to endpoint 'http://localhost:8080/jsonrpc4j/api'

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1	{"id":"1","jsonrpc":"2.0","method":"printPersons","params":{"persons":[{"name":"Solar","yearOfBirth":1980},{"name":"City","yearOfBirth":1988}]}}

Download Source Code

7. Implement your own JSON RCP Client

It is quite simple to write a controller to invoke JSON-RPC API by using JsonRpcRestClient

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@RequestMapping(value = "multiplier") @ResponseBody public Object getMultiplierResult(@RequestParam("a") long a, @RequestParam("b") long b) {     try {         URL url = new URL(getAPIUrl());         JsonRpcRestClient client = new JsonRpcRestClient(url);         Map<String, Object> params = new HashMap<>();         params.put("a", a);         params.put("b", b);         Long result = client.invoke("multiplier", params, Long.class);         return String.valueOf(result);     } catch (Throwable t) {         logger.log(Level.SEVERE, "Error while invoking multiplier API", t);     }     return null; }

Download JSON RCP Client Source Code

8. Deploy JSON RCP Client and Test

8.1. Deploy JSON RPC Client

'SpringJsonRPCClient' can be deployed in the same Glassfish with package 'SpringJsonRPCExample'

8.2. Test JSON RPC Client

Enter the appropriated urls to web browser to invoke API

http://localhost:8080//jsonrpc4j-client/multiplier?a=1111111&b=1111111

http://localhost:8080//jsonrpc4j-client/printperson

http://localhost:8080//jsonrpc4j-client/printpersons