如何在HazelcastJsonValue中使用聚合？

问题描述

如何对HazelcastJsonValue使用聚合？

我正在尝试使用：

Long count = map1.aggregate(Aggregators.count(),e -> "name='John'".equals(e.getValue()));        
Long count = map1.aggregate(Aggregators.count("name='John'"));

但是在两种情况下我都得到0，而实际结果应该是4。

这是示例代码：

    HazelcastInstance hazelCast = Hazelcast.newHazelcastInstance();
    IMap<String,HazelcastJsonValue> map1 = hazelCast.getMap("map1");

    map1.put("1",new HazelcastJsonValue("{"name":"John","age":31,"city":"New York"}"));
    map1.put("2","city":"New York"}"));
    map1.put("3","city":"New York"}"));
    map1.put("4","city":"New York"}"));
    
    Long count = map1.aggregate(Aggregators.count(),e -> "name='John'".equals(e.getValue()));
    Long count = map1.aggregate(Aggregators.count("name='John'"));

    System.out.println(count);

解决方法

在我看来，谓词的格式不正确-在第一个谓词中，您将使用“等号”对整个JSON文档（多个字段）与文档的一部分进行比较，因此它永远不会匹配。

对我有用的是：

Config c = new Config();
HazelcastInstance hazelCast = Hazelcast.newHazelcastInstance(c);
IMap<String,HazelcastJsonValue> map1 = hazelCast.getMap("map1");

HazelcastJsonValue jsv = new HazelcastJsonValue("{\"name\":\"John\",\"age\":31,\"city\":\"New York\"}");
map1.put("A",jsv);
map1.put("B",jsv);

Predicate p = Predicates.equal("name","John");
long count = map1.aggregate(Aggregators.count(),p);
System.out.println("Count: " + count);
hazelCast.shutdown();

hazelcast java java