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
java
<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
java
nebula:
address[0]:
host: 192.168.40.130
port: 9669
username: root
password: root
reconnect: false
space: 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
@AllArgsConstructor
public 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 {
@Resource
Session 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 {
@Resource
NebulaTemplate 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
sql
//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;