工作需求，开始了解图数据库，经过工具选型，最终选择nebula graph，并集成到springboot，java 环境下如何对 Nebula Graph 进行操作，本文整理下过程。
1、首先引入 pom 依赖
<dependency><groupId>com.vesoft</groupId><artifactId>client</artifactId><version>3.0.0</version>
</dependency>
为方便解析 json ，这里把 fastjson 也引进来。
<dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.78</version>
</dependency>2、配置文件中配置 Nebula 的信息
nebula:address[0]:host: 192.168.40.130port: 9669username: rootpassword: rootreconnect: falsespace: javatest3、java配置过程，文件结构如下：
1）声明 NebulaProperties 接收上面的配置信息：
@Data
public class NebulaAddress {private String host;private Integer port;
}@Data
@Configuration
@ConfigurationProperties(prefix = "nebula")
public class NebulaProperties {private List<NebulaAddress> address;private String username;private String password;private boolean reconnect;private String space;
}2）声明 NebulaConstant 把常用的字符串声明在这里：
public class NebulaConstant {public static final String USE = "USE ";public static final String SEMICOLON = "; ";public static final String ERROR_CODE = "-1";@Getter@AllArgsConstructorpublic enum NebulaJson{ERRORS("errors"),CODE("code"),MESSAGE("message"),RESULTS("results"),COLUMNS("columns"),DATA("data"),ROW("row");private String key;}
}
3）声明 NebulaConfig ，初始化 NebulaPool ，及声明 Session 的获取方式：
-
便对结果的解析，再声明一个 NebulaResult 用来接收结果：
@Data public class NebulaResult<T> {private Integer code;private String message;private List<T> data;public boolean isSuccessed(){return code == 0;} }
4）为了方便对结果的解析，再声明一个 NebulaResult 用来接收结果：
@Data
public class NebulaResult<T> {private Integer code;private String message;private List<T> data;public boolean isSuccessed(){return code == 0;}
}
5）每次都是使用 Session 未免太麻烦，这里封装一个 NebulaTemplate 返回上面 对象 ：
@Slf4j
@Component
public class NebulaTemplate {@ResourceSession session;public <T> NebulaResult<T> queryObject(String stmt, Class<T> tClass) {NebulaResult<T> nebulaResult = executeObject(stmt);if (Objects.isNull(nebulaResult.getData())) {return nebulaResult;}Optional.ofNullable(nebulaResult.getData()).ifPresent(data -> nebulaResult.setData(data.stream().map(d -> JSONObject.toJavaObject(((JSONObject) d), tClass)).collect(Collectors.toList())));return nebulaResult;}public NebulaResult executeObject(String stmt) {JSONObject jsonObject = executeJson(stmt);return JSONObject.toJavaObject(jsonObject, NebulaResult.class);}public JSONObject executeJson(String stmt) {JSONObject restJson = new JSONObject();try {JSONObject jsonObject = JSON.parseObject(Objects.requireNonNull(session).executeJson(stmt));JSONObject errors = jsonObject.getJSONArray(NebulaConstant.NebulaJson.ERRORS.getKey()).getJSONObject(0);restJson.put(NebulaConstant.NebulaJson.CODE.getKey(), errors.getInteger(NebulaConstant.NebulaJson.CODE.getKey()));if (errors.getInteger(NebulaConstant.NebulaJson.CODE.getKey()) != 0) {restJson.put(NebulaConstant.NebulaJson.MESSAGE.getKey(), errors.getString(NebulaConstant.NebulaJson.MESSAGE.getKey()));return restJson;}JSONObject results = jsonObject.getJSONArray(NebulaConstant.NebulaJson.RESULTS.getKey()).getJSONObject(0);JSONArray columns = results.getJSONArray(NebulaConstant.NebulaJson.COLUMNS.getKey());if (Objects.isNull(columns)) {return restJson;}JSONArray data = results.getJSONArray(NebulaConstant.NebulaJson.DATA.getKey());if (Objects.isNull(data)) {return restJson;}List<JSONObject> resultList = new ArrayList<>();data.stream().map(d -> (JSONObject) d).forEach(d -> {JSONArray row = d.getJSONArray(NebulaConstant.NebulaJson.ROW.getKey());JSONObject map = new JSONObject();for (int i = 0; i < columns.size(); i++) {map.put(columns.getString(i), row.get(i));}resultList.add(map);});restJson.put(NebulaConstant.NebulaJson.DATA.getKey(), resultList);} catch (Exception e) {restJson.put(NebulaConstant.NebulaJson.CODE.getKey(), NebulaConstant.ERROR_CODE);restJson.put(NebulaConstant.NebulaJson.MESSAGE.getKey(), e.toString());log.error("nebula execute err：", e);}return restJson;}
}
4、测试
@RestController
public class TestController {@ResourceNebulaTemplate nebulaTemplate;@GetMapping("/addVertex")public Object addJSON() throws IOErrorException {String sql = "insert vertex team(team_name, persion_num) values \"team_2\":(\"team_2\", 43);";NebulaResult nebulaResult = nebulaTemplate.executeObject(sql);return nebulaResult;}@GetMapping("/findVertex")public Object findJson2() throws IOErrorException {String sql = "lookup on team yield id(vertex) AS id,properties(vertex).persion_num AS persion_num,properties(vertex).team_name AS team_name;";NebulaResult<Info> infoNebulaResult = nebulaTemplate.queryObject(sql, Info.class);return infoNebulaResult;}
}5、常用的nSQL语句
//查看所有边
LOOKUP ON follow YIELD edge AS e;//搜索点
LOOKUP ON entity WHERE entity.name == "20元的东西" YIELD properties(vertex).name as name, properties(vertex).cntt as cntt, properties(vertex).sid as sid, properties(vertex).syspath as syspath;//由一点查看关联的所有点
GO FROM "20元的东西" OVER follow BIDIRECT YIELD dst(edge) AS destination;//查全部点
MATCH (v) RETURN v limit 100;//以下是删除所有的边
LOOKUP ON follow YIELD src(edge) AS src, dst(edge) AS dst | DELETE EDGE follow $-.src -> $-.dst @0;//从一点批量删除边
GO FROM "20元的东西" OVER * BIDIRECT YIELD src(edge) AS src, dst(edge) AS dst | DELETE EDGE follow $-.src -> $-.dst @0;//批量删除点
LOOKUP ON entity YIELD id(vertex) as id| DELETE VERTEX $-.id;//复合查询
LOOKUP ON entity WHERE entity.name == "20元的东西" YIELD id(vertex) as id | GO FROM $-.id OVER follow YIELD dst(edge) AS id | GO FROM $-.id OVER follow WHERE properties($$).name == "20元的东西的子节点" YIELD properties($$) as obj;
