使用Jersey和Tomcat将Spring Data Neo4j集成（Maven）在Dynamic Web Project中

Question

I´m getting a little bit lost in my own (maven enabled) dynamic WEB - Project. The project works fine, I´ve got a RESTful WebService (Jersey) running and I´m able to consume it.

... my next step was to persist my domain classes, with Spring Data and Neo4j. So, I´ve added some tags to my pom.xml

...
<repository>
  <id>spring-milestone</id>
  <name>Spring Maven MILESTONE Repository</name>
  <url>http://maven.springframework.org/milestone</url>
</repository>

<dependency>
  <groupId>org.springframework.data</groupId>
  <artifactId>spring-data-neo4j</artifactId>
  <version>2.0.0.RELEASE</version>
</dependency>
...

my next step was to annotate my entity-classes... here is a simple example:

...
@NodeEntity
public class Category {

@GraphId Long nodeId;
String categoryType;

public Category(String categoryType){
    this.categoryType = categoryType;
}

}
...

okay, everything´s fine... now I want to persist my category-object...

@Autowired Neo4jTemplate template;
@Test @Transactional 
public void toGraphDb() {

      template.save(new Category("mashineCategory"));
}   

when I run the test I´m getting a NullPointerException, cause the template is null

I guess there is something missing in my project, but I´m not sure in which folder/file to add informations/files...

here is my web.xml:

...
<display-name>ElisaSimulatorM4</display-name>

<servlet>
  <servlet-name>Jersey REST Service</servlet-name>
   <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
<init-param>
  <param-name>com.sun.jersey.config.property.packages</param-name>
  <param-value>de.elisa.communication.webservice.restservice.implementation</param-value>
  </init-param>
  <load-on-startup>1</load-on-startup>
</servlet>


<servlet-mapping>
  <servlet-name>Jersey REST Service</servlet-name>
  <url-pattern>/rest/*</url-pattern>
</servlet-mapping>
...

in some guides I read something about dispatcherServlets and an applicatonContext.xml, but I have no idea where to put it in my project.

Maybe someone can help me out...

Ps. I wanted to upload a screenshot from my project-tree but as a greenhorn I haven't got enough reputation... sorry for that

Answer 1

Perhaps it is best to look into the supplied examples of Spring Data Neo4j http://spring.neo4j.org/examples there are some for simple projects like hello-world and some for more advanced web-applications cineasts.

To get the idea the Spring Documentation about the general setup of a Spring(Web) application should help you.

You should probably start with a console application to get the ideas and then incorporate that in your web-application.

The applicationContext.xml file is the SpringFramework configuration file. It should be enough to have a minimal one, like this from the hello-world example.

Put it in src/main/resources/applicationContext.xml

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:neo4j="http://www.springframework.org/schema/data/neo4j"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/data/neo4j http://www.springframework.org/schema/data/neo4j/spring-neo4j-2.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">

    <context:spring-configured/>
    <context:annotation-config/>

    <neo4j:config storeDirectory="path/to/db"/>
    <neo4j:repositories base-package="org.example.repository"/>

</beans>

Answer 2

Ran into the same issue after copying the sample code from Good Relationships and trying to "conjure the magic" of spring. AutoWiring is magic, but not quite magic enough without loading the class through Spring's application context. The following works for a standalone client.

    ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("standaloneAppContext.xml");

    Test test = ctx.getBean(Test.class);