转发：Spring Boot 访问Neo4j

Posted 2020-08-21

（原文：https://my.oschina.net/syic/blog/798104）

在Spring Boot中访问Neo4j，通过Spring Data Neo4j可以轻易地实现。

例如，现有如下图所示的数据模型：

这表示有两个节点：用户和组，并且这两个节点的关系是从属关系，即用户从属于组。

根据这个数据模型，使用Spring Data Neo4j进行建模。

用户节点建模：

package com.demo.neo4j.domain;

import org.neo4j.ogm.annotation.GraphId;
import org.neo4j.ogm.annotation.NodeEntity;
import org.neo4j.ogm.annotation.Relationship;

@NodeEntity
public class User {
   @GraphId
   private Long id;
   private String name;

   @Relationship(type = "从属", direction = Relationship.OUTGOING)
   private Group group;

   public User() {
   }

   public Long getId() {
      return id;
   }

   public void setId(Long id) {
      this.id = id;
   }

   public String getName() {
      return name;
   }

   public void setName(String name) {
      this.name = name;
   }

   public Group getGroup() {
      return group;
   }

   public void setGroup(Group group) {
      this.group = group;
   }
}

　　

组节点建模：

package com.demo.neo4j.domain;

import org.neo4j.ogm.annotation.GraphId;

public class Group {
    @GraphId
    private Long id;
    private String name;

    public Group() {
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

　　

数据持久化设计：

package com.demo.neo4j.repository;

import com.demo.neo4j.domain.User;
import org.springframework.data.neo4j.repository.GraphRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface UserRepository extends GraphRepository<User> {
    User findByName(String name);
}

　　

使用嵌入式方式连接数据库：

compiler=org.neo4j.ogm.compiler.MultiStatementCypherCompiler
driver=org.neo4j.ogm.drivers.embedded.driver.EmbeddedDriver
URI=file:///test/graph.db

　　

测试用例：

package com.demo.neo4j.test;

import com.demo.neo4j.config.Neo4jConfig;
import com.demo.neo4j.domain.Group;
import com.demo.neo4j.domain.User;
import com.demo.neo4j.repository.UserRepository;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.util.Assert;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {Neo4jConfig.class})
public class Neo4jTest {
    private static Logger log = LoggerFactory.getLogger(Neo4jTest.class);

    @Autowired
    private UserRepository userRepository;

    @Before
    public void addData() {
        Group group = new Group();
        group.setName("admins");

        User user = new User();
        user.setName("admin");
        user.setGroup(group);

        userRepository.save(user);
        Assert.notNull(user.getId());
    }

    @Test
    public void getData() {
        User user = userRepository.findByName("admin");
        Assert.notNull(user);
        log.info("\n================== user name={}; group name={} ==================",
                user.getName(), user.getGroup().getName());
    }
}

　　

运行结果：

================== user name=admin; group name=admins ==================