Neo4j+SpringBoot实现节点以及关系的增删改查（Spring Data Neo4j）
公司让学习一下Neo4j在SpringBoot框架下的使用，我知道有个Spring DATA Neo4J，在网上找了很多教程，有些地方让我困惑了很久，所以记下来希望能给后面学习的伙伴一些帮助。
先上效果图：
一、开发环境
IDE：idea
JDK：1.8
先搭建一个普通的SpringBoot项目，然后导入依赖。
yml配置：
spring:
data:
neo4j:
uri: bolt://localhost:7687
username: neo4j
password: cldev
pom.xml如下：
4.0.0
org.springframework.boot
spring-boot-starter-parent
2.3.2.RELEASE
com.example
neo4jdemo
0.0.1-SNAPSHOT
neo4jdemo
Demo project for Spring Boot
1.8
org.springframework.boot
spring-boot-starter-data-neo4j
org.neo4j
neo4j-ogm-core
3.2.14
org.springframework.data
spring-data-neo4j
5.3.2.RELEASE
com.voodoodyne.jackson.jsog
jackson-jsog
1.1
compile
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-test
test
org.junit.vintage
junit-vintage-engine
org.springframework.boot
spring-boot-maven-plugin
二、代码部分
为了简单，本项目节点只设置一种类型（User），实现的关系的某一个User知道另一User，关系（Know）。
首先编写User节点类（UserNode .java）：
package com.example.neo4jdemo.entity.node;
import com.fasterxml.jackson.annotation.JsonIdentityInfo;
import com.voodoodyne.jackson.jsog.JSOGGenerator;
import org.neo4j.ogm.annotation.*;
import java.util.HashSet;
import java.util.Set;
@JsonIdentityInfo(generator= JSOGGenerator.class)
@NodeEntity(label = "User")
public class UserNode {
@Id
@GeneratedValue
private Long nodeId;
@Property(name = "name")
private String name;
@Property(name = "age")
private int age;
@Property(name = "sex")
private String sex;
/*注意这个地方：并不是说加了这个注解，然后下面实现了addKnows这个方法在以后调用addKnows
就可以实现关系的增加，这是不对的，我看了很多教程没有说明。这个addKnows方法，只有在节点未被
添加之前，调用该方法添加关系，然后再调用UserService中的create方法，这样关系才会同时被添加到图
数据库中。如果想实现两个已有节点之间增加关系，需要单独实现*/
@Relationship(type = "know" ,direction = Relationship.OUTGOING)
private Set knows = new HashSet<>();
public Long getNodeId() {
return nodeId;
}
public void setNodeId(Long nodeId) {
this.nodeId = nodeId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Set getKnows() {
return knows;
}
public void setKnows(Set knows) {
this.knows = knows;
}
public Boolean addKnows(UserNode to){
return this.knows.add(to);
}
@Override
public String toString() {
return "UserNode{" +
"nodeId=" + nodeId +
", name='" + name + '\'' +
", age=" + age +
", sex='" + sex + '\'' +
'}';
}
public UserNode() {}
}
关系类（Know.java）
package com.example.neo4jdemo.entity.relationship;
import com.example.neo4jdemo.entity.node.UserNode;
import com.fasterxml.jackson.annotation.JsonIdentityInfo;
import com.voodoodyne.jackson.jsog.JSOGGenerator;
import org.neo4j.ogm.annotation.*;
/**
* @program: neo4jdemo
* @description: 知道关系类
* @author: chen
* @create: 2020-07-27
**/
@JsonIdentityInfo(generator= JSOGGenerator.class)
@RelationshipEntity(type = "know")
public class Know {
@Id
@GeneratedValue
private Long id;
@StartNode
private UserNode from;
@EndNode
private UserNode to;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public UserNode getFrom() {
return from;
}
public void setFrom(UserNode from) {
this.from = from;
}
public UserNode getTo() {
return to;
}
public void setTo(UserNode to) {
this.to = to;
}
public Know() {
}
public Know(UserNode from, UserNode to) {
this.from = from;
this.to = to;
}
@Override
public String toString() {
return "Know{" +
"id=" + id +
", from=" + from +
", to=" + to +
'}';
}
}
KnowRepository.java
package com.example.neo4jdemo.repository;
import com.example.neo4jdemo.entity.relationship.Know;
import org.springframework.data.neo4j.annotation.Query;
import org.springframework.data.neo4j.repository.Neo4jRepository;
import org.springframework.data.repository.query.Param;
/**
* @program: neo4jdemo
* @description: 知道关系接口类
* @author: chen
* @create: 2020-07-27
**/
public interface KnowRepository extends Neo4jRepository {
@Query("MATCH (fromNode) WHERE id(fromNode) = {fromId} MATCH (toNode) WHERE id(toNode) = {toId} MATCH (fromNode)-[r]->(toNode) DELETE r")
void deleteByNodeId(@Param(value = "fromId") long fromId,@Param(value = "toId") long toId);
}
UserRepository.java
基础的增删改查Spring Data Neo4j已经封装好在Neo4jRepository里面了。
package com.example.neo4jdemo.repository;
import com.example.neo4jdemo.entity.node.UserNode;
import org.springframework.data.neo4j.annotation.Query;
import org.springframework.data.neo4j.repository.Neo4jRepository;
import org.springframework.data.repository.query.Param;
import org.springframework.stereotype.Repository;
@Repository
public interface UserRepository extends Neo4jRepository {
// @Query("MATCH (n:User) RETURN n ")
// List getUserNodeList();
//
// @Query("create (n:User{name:{name},age:{age},sex:{sex}}) RETURN n ")
// UserNode addUserNode(@Param("name") String name, @Param("age")int age, @Param("sex") String sex);
@Query("MATCH (n) WHERE id(n) = :#{#userNode.nodeId} SET n.name = :#{#userNode.name},n.age = :#{#userNode.age},n.sex = :#{#userNode.sex} RETURN n")
UserNode updateByNode(@Param("userNode") UserNode userNode);
}
UserService.java
package com.example.neo4jdemo.service;
import com.example.neo4jdemo.entity.node.UserNode;
import com.example.neo4jdemo.entity.relationship.Know;
import java.util.List;
import java.util.Optional;
public interface UserService {
/**
* @Description: 添加user节点
* @Params: [UserNode]
* @return: int
* @Author: chen
* @Date: 2020/7/27
*/
UserNode create(UserNode userNode);
/**
* @Description: 删除
* @Author: chen
* @Date: 2020/7/27
*/
void deleteById(Long id);
/**
* @Description: 查询
* @Author: chen
* @Date: 2020/7/27
* @return
*/
Optional findById(long id);
/**
* @Description: 获取所有User节点
* @Params: null
* @return: List
* @Author: chen
* @Date: 2020/7/27
*/
List findAll();
/**
* @Description: 增加“知道”关系
* @Author: chen
* @Date: 2020/7/27
*/
Know addIKnows(UserNode fromNode, UserNode toNode);
UserNode updateByNode(UserNode userNode);
void deleteKnowByNodeId(long fromId,long toId);
}
UserServiceImpl.java
package com.example.neo4jdemo.service.impl;
import com.example.neo4jdemo.entity.node.UserNode;
import com.example.neo4jdemo.entity.relationship.Know;
import com.example.neo4jdemo.repository.KnowRepository;
import com.example.neo4jdemo.repository.UserRepository;
import com.example.neo4jdemo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
import java.util.Optional;
@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserRepository userRepository;
@Autowired
private KnowRepository knowRepository;
@Override
public UserNode create(UserNode userNode) {
return userRepository.save(userNode);
}
@Override
public void deleteById(Long id) {
userRepository.deleteById(id);
}
@Override
public Optional findById(long id) {
return userRepository.findById(id);
}
@Override
public List findAll() {
return (List) userRepository.findAll();
}
@Override
public Know addIKnows(UserNode fromNode, UserNode toNode) {
Know newKnow = new Know(fromNode,toNode);
return knowRepository.save(newKnow);
}
@Override
public UserNode updateByNode(UserNode userNode) {
return userRepository.updateByNode(userNode);
}
@Override
public void deleteKnowByNodeId(long fromId, long toId) {
knowRepository.deleteByNodeId(fromId,toId);
}
}
UserController.java
package com.example.neo4jdemo.controller;
import com.example.neo4jdemo.entity.node.UserNode;
import com.example.neo4jdemo.entity.relationship.Know;
import com.example.neo4jdemo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;
import java.util.Optional;
/**
* @program: neo4jdemo
* @description: 控制层
* @author: chen
* @create: 2020-07-27
**/
@RestController
public class UserController {
@Autowired
private UserService userService;
/**
* @Description: 添加节点
* @Author: chen
* @Date: 2020/7/27
*/
@RequestMapping(path = "/add", method = RequestMethod.POST)
public UserNode addUserNode(@RequestBody UserNode userNode) {
return userService.create(userNode);
}
/**
* @Description: 根据id删除
* @Author: chen
* @Date: 2020/7/27
*/
@RequestMapping(path = "/delete", method = RequestMethod.POST)
public int delUserNodeById(@RequestParam(value = "id") long id) {
userService.deleteById(id);
System.out.println(id);
return 1;
}
/**
* @Description: 根据id更新
* @Author: chen
* @Date: 2020/7/27
*/
@RequestMapping(path = "/update", method = RequestMethod.POST)
public UserNode updateUserNodeByNode(@RequestBody UserNode userNode) {
return userService.updateByNode(userNode);
}
@RequestMapping(path = "/get", method = RequestMethod.GET)
public UserNode getUserNodeById(@RequestParam(value = "id") long id) {
Optional optionalUserNode = userService.findById(id);
if(optionalUserNode.isPresent()){
return optionalUserNode.get();
}else{
return null;
}
}
/**
* @Description: 查找所有节点
* @Author: chen
* @Date: 2020/7/27
*/
@RequestMapping(path = "/list", method = RequestMethod.GET)
public List getUserNodeList() {
return userService.findAll();
}
@RequestMapping(path = "/addKnows", method = RequestMethod.POST)
public Know addKnowsById(@RequestParam(value = "from") long fromId, @RequestParam(value = "to") long toId) {
Optional fromOpt = userService.findById(fromId);
Optional toOpt = userService.findById(toId);
if(fromOpt.isPresent()&&toOpt.isPresent()){
return userService.addIKnows(fromOpt.get(),toOpt.get());
}else{
return null;
}
}
@RequestMapping(path = "/delKnows", method = RequestMethod.POST)
public String deleteKnowsByNodeId(@RequestParam(value = "from") long fromId, @RequestParam(value = "to") long toId) {
Optional fromOpt = userService.findById(fromId);
Optional toOpt = userService.findById(toId);
if(fromOpt.isPresent()&&toOpt.isPresent()){
userService.deleteKnowByNodeId(fromId,toId);
return "ok";
}else{
return "false";
}
}
}
Neo4jConfig.java 我也不知道干啥的
package com.example.neo4jdemo.config;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.neo4j.repository.config.EnableNeo4jRepositories;
import org.springframework.transaction.annotation.EnableTransactionManagement;
@Configuration
@EnableNeo4jRepositories(basePackages = "com.example.neo4jdemo.repository")
@EnableTransactionManagement // 激活SDN隐式事务
public class Neo4jConfig {
}
重点就是User中的那段注释，是我困扰了很久的问题，希望大家能够避坑。有什么问题可以留言。