java连接neo4j测试

java连接neo4j测试

添加依赖

      <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-neo4j</artifactId>
        </dependency>

代码

    public static void main(String[] args) {
        Driver driver = GraphDatabase.driver("bolt://localhost:7687");
        Session session = driver.session();
        //这里注意 ，之前的版本字段注入是使用的{}，现在新版本的使用的$
        //创建一个person 节点 name=tom，address=北京
        session.run("CREATE (n:person {name:$name,address: $address})",
                parameters("name", "tom", "address", "北京"));
        //创建一个person 节点 name=night，address=四川
        session.run("CREATE (n:person {name:$name,address: $address})",
                parameters("name", "night", "address", "四川"));
        //查询person节点的name字段为night的节点
        Result result = session.run( "MATCH (a:person) WHERE a.name = $name " +
                        "RETURN a.name AS name, a.address AS address",
                parameters( "name", "night"));
        while (result.hasNext()) {
            Record record = result.next();
            System.out.println( record.get( "address" ).asString() + "" + record.get( "name" ).asString() );
        }
        //为night到tom节点建立一个属性relation=邻居的关系
        session.run(" match (n:person{name:$name1}),(q:person{name:$name}) create (n) -[l:link{relation:$relation}] ->(q)",
                parameters("name1", "night", "name", "tom", "relation", "邻居"));

        session.close();
        driver.close();
    }

注意点

这里有个注意点：两个person节点都通过name属性节点来关联的，使用占位符的时候注意使用不同名称的占位符，否则相同的情况下，前一个name的值会被后来的name值覆盖

底层源码的解析方式：将parameters入参拆分为一对key-value，前面是key，后面是value，相同的key的值会被覆盖

 public static Value parameters(Object... keysAndValues) {
        if (keysAndValues.length % 2 != 0) {
            throw new ClientException("Parameters function requires an even number of arguments, alternating key and value. Arguments were: " + Arrays.toString(keysAndValues) + ".");
        } else {
            HashMap<String, Value> map = Iterables.newHashMapWithSize(keysAndValues.length / 2);

            for(int i = 0; i < keysAndValues.length; i += 2) {
                Object value = keysAndValues[i + 1];
                Extract.assertParameter(value);
                map.put(keysAndValues[i].toString(), value(value));
            }

            return value((Object)map);
        }
    }