如何在数据库中存储Map<String、BigDecimal>

import com.fasterxml.jackson.databind.ObjectMapper;
import java.math.BigDecimal;
import java.util.HashMap;
import java.util.Map;

public class MapStorageExample {
    public static void main(String[] args) throws Exception {
        Map<String, BigDecimal> map = new HashMap<>();
        map.put("key1", new BigDecimal("1.23"));
        map.put("key2", new BigDecimal("4.56"));

        ObjectMapper objectMapper = new ObjectMapper();
        String json = objectMapper.writeValueAsString(map);

        // 存储到数据库
        String sql = "INSERT INTO my_table (map_data) VALUES (?)";
        // 执行SQL语句...

        // 从数据库读取
        String selectSql = "SELECT map_data FROM my_table WHERE id = ?";
        // 执行SQL语句...
        String resultJson = // 从数据库读取到的JSON字符串
        Map<String, BigDecimal> resultMap = objectMapper.readValue(resultJson, Map.class);
    }
}

import java.math.BigDecimal;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;

public class RelationalTableStorageExample {
    public static void main(String[] args) throws SQLException {
        Map<String, BigDecimal> map = new HashMap<>();
        map.put("key1", new BigDecimal("1.23"));
        map.put("key2", new BigDecimal("4.56"));

        // 存储到数据库
        String insertSql = "INSERT INTO map_table (key, value) VALUES (?, ?)";
        try (Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "user", "password");
             PreparedStatement pstmt = conn.prepareStatement(insertSql)) {
            for (Map.Entry<String, BigDecimal> entry : map.entrySet()) {
                pstmt.setString(1, entry.getKey());
                pstmt.setBigDecimal(2, entry.getValue());
                pstmt.executeUpdate();
            }
        }

        // 从数据库读取
        String selectSql = "SELECT key, value FROM map_table WHERE key = ?";
        try (Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "user", "password");
             PreparedStatement pstmt = conn.prepareStatement(selectSql)) {
            pstmt.setString(1, "key1");
            try (ResultSet rs = pstmt.executeQuery()) {
                Map<String, BigDecimal> resultMap = new HashMap<>();
                while (rs.next()) {
                    resultMap.put(rs.getString("key"), rs.getBigDecimal("value"));
                }
            }
        }
    }
}

import com.mongodb.client.MongoClient;
import com.mongodb.client.MongoClients;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import org.bson.Document;
import java.math.BigDecimal;
import java.util.HashMap;
import java.util.Map;

public class NoSQLStorageExample {
    public static void main(String[] args) {
        Map<String, BigDecimal> map = new HashMap<>();
        map.put("key1", new BigDecimal("1.23"));
        map.put("key2", new BigDecimal("4.56"));

        MongoClient mongoClient = MongoClients.create("mongodb://localhost:27017");
        MongoDatabase database = mongoClient.getDatabase("mydb");
        MongoCollection<Document> collection = database.getCollection("mycollection");

        // 存储到数据库
        Document doc = new Document(map);
        collection.insertOne(doc);

        // 从数据库读取
        Document resultDoc = collection.find(new Document("key", "key1")).first();
        Map<String, BigDecimal> resultMap = resultDoc.entrySet().stream()
                .collect(HashMap::new, (m, e) -> m.put(e.getKey(), new BigDecimal(e.getValue().toString())), HashMap::putAll);
    }
}