Exception in thread “main” com.sun.jersey.api.client.ClientHandlerException: java.net.ConnectException: Connection refused: connect

Question

I use neo4j 2.2.4

I try this program ,and this is my test code

package neo4j.rest.client;
import javax.ws.rs.core.MediaType;
import org.json.JSONObject;
import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.ClientResponse;
import com.sun.jersey.api.client.WebResource;
public class MyRestClient {
public static void main(String[] args) {
    MyRestClient jersey = new MyRestClient();
    jersey.createNode();
    jersey.sendCypher();        
}
public void createNode(){   
    //Create a REST Client
    Client client = Client.create();
    //Define a resource (REST Endpoint) which needs to be Invoked 
    //for creating a Node
    WebResource resource = client.resource("http://localhost:7474").path("/db/data/node");
    //Define properties for the node.
    JSONObject node = new JSONObject();
    node.append("Name", "John");        
    System.out.println(node.toString());        
    //Invoke the rest endpoint as JSON request
    ClientResponse res = resource.accept(MediaType.APPLICATION_JSON)
    .entity(node.toString())
    .post(ClientResponse.class);
    //Print the URI of the new Node
    System.out.println("URI of New Node = " + res.getLocation());       
}
public void sendCypher() {
    //Create a REST Client
    Client client = Client.create();
    //Define a resource (REST Endpoint) which needs to be Invoked 
    //for executing Cypher Query
    WebResource resource = client.resource("http://localhost:7474").path("/db/data/cypher");
    //Define JSON Object and Cypher Query
    JSONObject cypher = new JSONObject();
    cypher.accumulate("query", "match n return n limit 10");
    //Invoke the rest endpoint as JSON request
    ClientResponse res = resource.accept(MediaType.APPLICATION_JSON).entity(cypher.toString())
    .post(ClientResponse.class);
    //Print the response received from the Server
    System.out.println(res.getEntity(String.class));
}
}

And this is my error information,

{"Name":["John"]} Exception in thread "main" com.sun.jersey.api.client.ClientHandlerException: java.net.ConnectException: Connection refused: connect at com.sun.jersey.client.urlconnection.URLConnectionClientHandler.handle(URLConnectionClientHandler.java:149) at com.sun.jersey.api.client.Client.handle(Client.java:648) at com.sun.jersey.api.client.WebResource.handle(WebResource.java:670) at com.sun.jersey.api.client.WebResource.access$200(WebResource.java:74) at com.sun.jersey.api.client.WebResource$Builder.post(WebResource.java:553) at neo4j.rest.client.MyRestClient.createNode(MyRestClient.java:30) at neo4j.rest.client.MyRestClient.main(MyRestClient.java:14) Caused by: java.net.ConnectException: Connection refused: connect at java.net.DualStackPlainSocketImpl.connect0(Native Method) at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:69) at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:337) at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:198) at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:180) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:157) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:391) at java.net.Socket.connect(Socket.java:579) at java.net.Socket.connect(Socket.java:528) at sun.net.NetworkClient.doConnect(NetworkClient.java:180) at sun.net.www.http.HttpClient.openServer(HttpClient.java:388) at sun.net.www.http.HttpClient.openServer(HttpClient.java:483) at sun.net.www.http.HttpClient.(HttpClient.java:213) at sun.net.www.http.HttpClient.New(HttpClient.java:300) at sun.net.www.http.HttpClient.New(HttpClient.java:316) at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:992) at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:928) at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:846) at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:1087) at com.sun.jersey.client.urlconnection.URLConnectionClientHandler$1$1.getOutputStream(URLConnectionClientHandler.java:225) at com.sun.jersey.api.client.CommittingOutputStream.commitWrite(CommittingOutputStream.java:117) at com.sun.jersey.api.client.CommittingOutputStream.write(CommittingOutputStream.java:89) at sun.nio.cs.StreamEncoder.writeBytes(StreamEncoder.java:221) at sun.nio.cs.StreamEncoder.implFlushBuffer(StreamEncoder.java:291) at sun.nio.cs.StreamEncoder.implFlush(StreamEncoder.java:295) at sun.nio.cs.StreamEncoder.flush(StreamEncoder.java:141) at java.io.OutputStreamWriter.flush(OutputStreamWriter.java:229) at java.io.BufferedWriter.flush(BufferedWriter.java:254) at com.sun.jersey.core.util.ReaderWriter.writeToAsString(ReaderWriter.java:191) at com.sun.jersey.core.provider.AbstractMessageReaderWriterProvider.writeToAsString(AbstractMessageReaderWriterProvider.java:128) at com.sun.jersey.core.impl.provider.entity.StringProvider.writeTo(StringProvider.java:88) at com.sun.jersey.core.impl.provider.entity.StringProvider.writeTo(StringProvider.java:58) at com.sun.jersey.api.client.RequestWriter.writeRequestEntity(RequestWriter.java:300) at com.sun.jersey.client.urlconnection.URLConnectionClientHandler._invoke(URLConnectionClientHandler.java:204) at com.sun.jersey.client.urlconnection.URLConnectionClientHandler.handle(URLConnectionClientHandler.java:147) ... 6 more

Thank you.

Answer 1

• Check if your Neo4j server is up and running. Just open http://localhost:7474 in your browser.

• Your code would work if you use default settings of Neo4j. Because authorization is enabled by default. You have two options:

  1. Add authorization headers into your request

     client.addFilter(new HTTPBasicAuthFilter("neo4j","your_password"));

     • http://neo4j.com/docs/stable/rest-api-security.html

  2. Disable authorization

neo4j-server.properties

# Disable authorization
dbms.security.auth_enabled=false