Aerospike-如何在Java中反序列化包含对象的映射？

我从Aerospike DB加载地图时遇到问题。当我获取记录并尝试打印它时，我得到了下面的错误

Main

Key key = new Key( "test", "users", 2 );
Map<Integer, Widgets> map = new HashMap<>();
map.put(1, new Widgets(2, 2));
map.put(2, new Widgets(3, 0));
Bin bin = new Bin("widgets", map);
client.put( policy, key, bin );

存储在Aerospike中的数据

|                    | 2  | MAP('{1:AC ED 00 05 73 72 00 07 57 69 64 67 65 74 73 6F F3 7E F4 7F CD 1C 92 02 00 02 49 00 0A 63 6C 69 63 6B 43 6F 75 6E 74 49 00 09 76 69 65 77 43 6F 75 6E 74 78 70 00 00 00 02 00 00 00 02, 2:AC ED 00 05 73 72 00 07 57 69 64 67 65 74 73 6F F3 7E F4 7F  |
+--------------------+----+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.098 secs)

小部件类

public class Widgets implements Serializable{
    private int viewCount;
    private int clickCount;
    // getters, setters and constructors here
}

数据被毫无问题地存储在数据库中，但它被存储为字节数组。我无法反序列化它

编辑：

当我尝试打印地图时，确实会得到一个输出，但是当我尝试使用foreach时，它显示了一个错误

System.out.println(map); // works fine

输出

{1=Widgets@7e774085, 2=Widgets@3f8f9dd6} 

---

Aerospike始终将整数类型（short、int、long等）存储为数据库中的64位long。如果插入较短的数字类型，它将自动向上转换为较长的数字类型。这是为了支持没有较短数值类型的语言

因此，当您检索地图时，地图键将作为long返回。因此，此代码应替换您的检索代码：

        Record record = client.get(null, key); // using same key for testing
        Map<Long, Widgets> map2 = (Map<Long, Widgets>) record.getMap("widgets"); // here, I do get a map back... but its serialized 
        map2.forEach( (k,v) -> System.out.println(k));

通常，最好自己使用或序列化它们。例如，您可以将代码更改为：

package com.aerospike.play;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;

import com.aerospike.client.AerospikeClient;
import com.aerospike.client.Bin;
import com.aerospike.client.Key;
import com.aerospike.client.Record;

public class StackOverflowQuestion {
    public static class Widgets implements Serializable{
        private static final String VIEW_FIELD = "view";
        private static final String CLICK_FIELD = "click";

        private int viewCount;
        private int clickCount;

        public Widgets(int viewCount, int clickCount) {
                this.viewCount = viewCount;
                this.clickCount = clickCount;
        }
        public int getViewCount() {
            return viewCount;
        }
        public int getClickCount() {
            return clickCount;
        }

        @Override
        public String toString() {
                return String.format("{view: %d, count: %s}", viewCount, clickCount);
        }

        public Map<String, Object> asMap() {
                Map<String, Object> values = new HashMap<>();
                values.put(VIEW_FIELD, this.viewCount);
                values.put(CLICK_FIELD, this.clickCount);
                return values;
        }

        public static Widgets fromMap(Map<String, Object> map) {
                return new Widgets((int)(long)map.get(VIEW_FIELD), (int)(long)map.get(CLICK_FIELD));
        }
    }

    public static void main(String[] args) {
        AerospikeClient client = new AerospikeClient("172.28.128.4", 3000);
        Key key = new Key( "test", "users", 2 );
        Map<Integer, Map<String, Object>> map = new HashMap<>();
        map.put(1, new Widgets(2, 2).asMap());
        map.put(2, new Widgets(3, 0).asMap());
        Bin bin = new Bin("widgets", map);
        client.put( null, key, bin );

        Record record = client.get(null, key); // using same key for testing
        Map<Long, Map<String, Object>> map2 = (Map<Long, Map<String, Object>>) record.getMap("widgets"); 
        map2.forEach( (k,v) -> {
            Widgets w = Widgets.fromMap(v);
            System.out.printf("%d -> %s\n", k, w);
        });

        client.close();
    }
}

但存储在数据库中的数据使用的是本机类型：

aql> select * from test.users
*************************** 1. row ***************************
widgets: MAP('{1:{"view":2, "click":2}, 2:{"view":3, "click":0}}')

---

作为旁注，有更有效的方法来存储这些数据，如列表，但这种表示更具说明性。

当您得到异常时，回溯是什么？

aql> select * from test.users
*************************** 1. row ***************************
widgets: MAP('{1:AC ED 00 05 73 72 00 34 63 6F 6D 2E 74 69 6D 2E...

package com.aerospike.play;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;

import com.aerospike.client.AerospikeClient;
import com.aerospike.client.Bin;
import com.aerospike.client.Key;
import com.aerospike.client.Record;

public class StackOverflowQuestion {
    public static class Widgets implements Serializable{
        private static final String VIEW_FIELD = "view";
        private static final String CLICK_FIELD = "click";

        private int viewCount;
        private int clickCount;

        public Widgets(int viewCount, int clickCount) {
                this.viewCount = viewCount;
                this.clickCount = clickCount;
        }
        public int getViewCount() {
            return viewCount;
        }
        public int getClickCount() {
            return clickCount;
        }

        @Override
        public String toString() {
                return String.format("{view: %d, count: %s}", viewCount, clickCount);
        }

        public Map<String, Object> asMap() {
                Map<String, Object> values = new HashMap<>();
                values.put(VIEW_FIELD, this.viewCount);
                values.put(CLICK_FIELD, this.clickCount);
                return values;
        }

        public static Widgets fromMap(Map<String, Object> map) {
                return new Widgets((int)(long)map.get(VIEW_FIELD), (int)(long)map.get(CLICK_FIELD));
        }
    }

    public static void main(String[] args) {
        AerospikeClient client = new AerospikeClient("172.28.128.4", 3000);
        Key key = new Key( "test", "users", 2 );
        Map<Integer, Map<String, Object>> map = new HashMap<>();
        map.put(1, new Widgets(2, 2).asMap());
        map.put(2, new Widgets(3, 0).asMap());
        Bin bin = new Bin("widgets", map);
        client.put( null, key, bin );

        Record record = client.get(null, key); // using same key for testing
        Map<Long, Map<String, Object>> map2 = (Map<Long, Map<String, Object>>) record.getMap("widgets"); 
        map2.forEach( (k,v) -> {
            Widgets w = Widgets.fromMap(v);
            System.out.printf("%d -> %s\n", k, w);
        });

        client.close();
    }
}

1 -> {view: 2, count: 2}
2 -> {view: 3, count: 0}

aql> select * from test.users
*************************** 1. row ***************************
widgets: MAP('{1:{"view":2, "click":2}, 2:{"view":3, "click":0}}')