添加Spring Data Neo4j相关依赖
org.springframework.boot
spring-boot-starter-data-neo4j
org.neo4j
neo4j-ogm-http-driver
org.projectlombok
lombok
true
org.springframework.boot
spring-boot-starter-test
test
application.yml添加Neo4j环境配置
spring:
data:
neo4j:
uri: http://localhost:7474
username: neo4j
password: 123456
Neo4j中要定义节点，使用Spring Data Neo4j的注解@NodeEntity，标记该类为节点，节点名称为 StudentNode
@Getter
@Setter
@ToString
@NodeEntity
public class StudentNode {
/**
* neo4j 生成的id
*/
@Id
@GeneratedValue
private Long id;
/**
* 属性，name
*/
private String name;
/**
* 关系，定义为友谊
*/
@Relationship(type = "FRIENDSHIP_RELATION")
private List friendshipRelationList;
/**
* 添加友谊的关系
* @param friendshipRelation
*/
public void addRelation(FriendshipRelation friendshipRelation){
if(this.friendshipRelationList == null){
this.friendshipRelationList = new ArrayList<>();
}
this.friendshipRelationList.add(friendshipRelation);
}
}
Neo4j也要定义关系，使用Spring Data Neo4j的注解@RelationshipEntity，标记其为关系，关系名为 FRIENDSHIP_RELATION，在里面定义StartNode和EndNode
@Getter
@Setter
@Component
@RelationshipEntity(type = "FRIENDSHIP_RELATION")
public class FriendshipRelation {
@Id
@GeneratedValue
private Long id;
@StartNode
private StudentNode from;
@EndNode
private StudentNode to;
}
StudentNodeRepository为数据库操作，因为后面有删除关系，所以需要@Transactional
@Repository
@Transactional
public interface StudentRepository extends Neo4jRepository {
/**
* 通过name查找学生node
* @param name
* @return
*/
StudentNode findByName(String name);
/**
* 根据name获取学生 in 友谊关系
* @param name
* @return
*/
@Query("match " +
"p=(a:StudentNode) - [r:FRIENDSHIP_RELATION*0..] -> " +
"(b:StudentNode) " +
"where b.name = {0} " +
"return p")
List inFriendship(String name);
/**
* 根据name获取学生 out 友谊关系
* @param name
* @return
*/
@Query("match " +
"p=(b:StudentNode) " +
"- [rr:FRIENDSHIP_RELATION*0..] -> (c:StudentNode) " +
"where b.name = {0} " +
"return p")
List outFriendship(String name);
/**
* 根据name获取学生 both 友谊关系
* @param name
* @return
*/
@Query("match " +
"p=(a:StudentNode) <- [r:FRIENDSHIP_RELATION*0..] -> " +
"(b:StudentNode) " +
"<- [rr:FRIENDSHIP_RELATION*0..] -> (c:StudentNode) " +
"where b.name = {0} " +
"return p")
List bothFriendship(String name);
}
Neo4jServiceImpl中定义添加关系和删除关系，都需要保存from端的节点关系即可
删除节点时使用了find和save方法，需要添加@Transactional注解
@Service("neo4jServiceImpl")
public class Neo4jServiceImpl implements Neo4jService {
@Autowired
private StudentRepository studentRepository;
@Override
public void saveFriendship(String fromName, String toName) {
StudentNode from = studentRepository.findByName(fromName);
StudentNode to = studentRepository.findByName(toName);
FriendshipRelation friendshipRelation = new FriendshipRelation();
friendshipRelation.setFrom(from);
friendshipRelation.setTo(to);
//只需要在from节点保存关系即可
from.addRelation(friendshipRelation);
studentRepository.save(from);
}
//删除节点时，使用find，save 需要@Transactional注解
@Transactional(rollbackFor = Exception.class)
@Override
public void deleteFriendship(String fromName, String toName) {
StudentNode fromStudentNode = studentRepository.findByName(fromName);
List friendshipRelationList = fromStudentNode.getFriendshipRelationList();
for (Iterator iterator = friendshipRelationList.iterator(); iterator.hasNext();) {
FriendshipRelation relation = iterator.next();
StudentNode fromNode = relation.getFrom();
StudentNode toNode = relation.getTo();
String fromNodeName = fromNode.getName();
String toNodeName = toNode.getName();
//判断 fromName 和 toName 需要删除的关系是否相等
if(fromNodeName.equals(fromName) && toNodeName.equals(toName)){
iterator.remove();
}
}
//只需要在from节点保存关系即可
studentRepository.save(fromStudentNode);
}
}
Neo4jTest进行测试，均可成功
@RunWith(SpringRunner.class)
@SpringBootTest
public class Neo4jTest {
@Autowired
private StudentRepository studentRepository;
@Autowired
private Neo4jService neo4jService;
/**
* 保存单个节点
*/
@Test
public void saveStudentNode(){
StudentNode studentNode = new StudentNode();
studentNode.setName("张0");
studentRepository.save(studentNode);
}
/**
* 通过name查询学生节点
*/
@Test
public void findStudentNodeByName(){
StudentNode studentNode = studentRepository.findByName("张0");
System.out.println("");
}
/**
* 保存批量节点
*/
@Test
public void saveAllStudentNode(){
List studentNodeList = new ArrayList<>();
StudentNode studentNode;
for(int i = 1; i <= 10; i++){
studentNode = new StudentNode();
studentNode.setName("张" + i);
studentNodeList.add(studentNode);
}
studentRepository.saveAll(studentNodeList);
}
/**
* 查询全部
*/
@Test
public void findAll(){
//iterable to list
List studentNodeList = Lists.newArrayList(studentRepository.findAll());
System.out.println("");
}
/**
* 分页查询
*/
@Test
public void pageFindAll(){
Pageable pageable = PageRequest.of(0,2);
Page studentNodePage = studentRepository.findAll(pageable);
System.out.println("");
}
/**
* 保存如下友谊关系
*
* 1 <-> 2 <-> 5 -> 9
* -> 6
* -> 3 <-> 7 -> 10
* -> 4 <-> 8
*/
@Test
public void saveFriendship(){
neo4jService.saveFriendship("张1","张2");
neo4jService.saveFriendship("张1","张3");
neo4jService.saveFriendship("张1","张4");
neo4jService.saveFriendship("张2","张1");
neo4jService.saveFriendship("张2","张5");
neo4jService.saveFriendship("张2","张6");
neo4jService.saveFriendship("张3","张7");
neo4jService.saveFriendship("张4","张8");
neo4jService.saveFriendship("张5","张2");
neo4jService.saveFriendship("张5","张9");
neo4jService.saveFriendship("张7","张3");
neo4jService.saveFriendship("张7","张10");
neo4jService.saveFriendship("张8","张4");
}
/**
* 根据name查询 both 友谊关系
*/
@Test
public void getBothFriendship(){
List friendshipRelationList1 = studentRepository.bothFriendship("张1");
}
/**
* 根据name查询 in 友谊关系
*/
@Test
public void getInFriendship(){
List friendshipRelationList1 = studentRepository.inFriendship("张1");
}
/**
* 根据name查询 out 友谊关系
*/
@Test
public void getOutFriendship(){
List friendshipRelationList1 = studentRepository.outFriendship("张1");
}
/**
* 删除 1 -> 3 友谊关系
*/
@Test
public void deleteFriendship(){
neo4jService.deleteFriendship("张1","张3");
}
}
保存单节点 张0
保存多节点 张1~张10
保存 张1~张10 友谊关系
删除 张1 和 张3 关系