[知识图谱]利用py2neo从Neo4j数据库获取数据

 # -*- coding: utf-8 -*-

 from py2neo import Graph
 import json
 import re

 class Neo4jToJson(object):
     """知识图谱数据接口"""

     def __init__(self):
         """初始化数据"""
         # 与neo4j服务器建立连接
         self.graph = Graph("http://IP//:7474", username="neo4j", password="xxxxx")
         self.links = []
         self.nodes = []

     def post(self):
         """与前端交互"""
         # 前端传过来的数据
         select_name = '南京审计大学'
         # 取出所有节点数据
         nodes_data_all = self.graph.run("MATCH (n) RETURN n").data()
         # node名存储
         nodes_list = []
         for node in nodes_data_all:
             nodes_list.append(node['n']['name'])
         # 根据前端的数据，判断搜索的关键字是否在nodes_list中存在，如果存在返回相应数据，否则返回全部数据
         if select_name in nodes_list:
             # 获取知识图谱中相关节点数据
             nodes_data = self.graph.run("MATCH (n)--(b) where n.name='" + select_name + "' return n,b").data()
             links_data = self.graph.run("MATCH (n)-[r]-(b) where n.name='" + select_name + "' return r").data()
             self.get_select_nodes(nodes_data)
         else:
             # 获取知识图谱中所有节点数据
             links_data = self.graph.run("MATCH ()-[r]->() RETURN r").data()
             nodes_data = self.graph.run("MATCH (n) RETURN n").data()
             self.get_all_nodes(nodes_data)

         self.get_links(links_data)

         # 数据格式转换
         neo4j_data = {'links': self.links, 'nodes': self.nodes}
         neo4j_data_json = json.dumps(neo4j_data, ensure_ascii=False).replace(u'\xa0', u'')
         return neo4j_data_json

     def get_links(self, links_data):
         """知识图谱关系数据获取"""
         links_data_str = str(links_data)
         links = []
         i = 1
         dict = {}
         # 正则匹配
         links_str = re.sub("[\!\%\[\]\,\。\{\}\-\:\'\(\)\>]", " ", links_data_str).split(' ')
         for link in links_str:
             if len(link) > 1:
                 if i == 1:
                     dict['source'] = link
                 elif i == 2:
                     dict['name'] = link
                 elif i == 3:
                     dict['target'] = link
                     self.links.append(dict)
                     dict = {}
                     i = 0
                 i += 1
         return self.links

     def get_select_nodes(self, nodes_data):
         """获取知识图谱中所选择的节点数据"""
         dict_node = {}
         for node in nodes_data:
             name = node['n']['name']
             tag = node['n']['tag']
             dict_node['name'] = name
             dict_node['tag'] = tag
             self.nodes.append(dict_node)
             dict_node = {}
             break
         for node in nodes_data:
             name = node['b']['name']
             tag = node['b']['tag']
             dict_node['name'] = name
             dict_node['tag'] = tag
             self.nodes.append(dict_node)
             dict_node = {}

     def get_all_nodes(self, nodes_data):
         """获取知识图谱中所有节点数据"""
         dict_node = {}
         for node in nodes_data:
             name = node['n']['name']
             tag = node['n']['tag']
             dict_node['name'] = name
             dict_node['tag'] = tag
             self.nodes.append(dict_node)
             dict_node = {}
         return self.nodes

 if __name__ == '__main__':
     data_neo4j = Neo4jToJson()
     print(data_neo4j.post())