Java中抽象类字段的多态性处理：JSON反序列化与运行时类型判断

public class Pipeline {
  private long id;
  private String name;
  private SourceConfig sourceConfig; // 抽象类型字段
  private SinkConfig sinkConfig;     // 抽象类型字段
  // ... 其他字段
}

public abstract class SourceConfig {
  private long id;
  private String name;
  // ... 构造函数、Getter/Setter
}

public class KafkaSourceConfig extends SourceConfig {
  private String topic;
  private String messageSchema;
  // ... 构造函数、Getter/Setter
}

public class MysqlSourceConfig extends SourceConfig {
  private String databaseName;
  private String tableName;
  // ... 构造函数、Getter/Setter
}

{
    "name": "mysql_to_bq_1",
    "sourceConfig": {
        "source": "MYSQL", // 如何根据这个标识符确定类型？
        "databaseName": "my_db",
        "tableName": "my_table"
    },
    "sinkConfig": {
        // ...
    },
    "createdBy": "paul"
}

import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;

// 在抽象基类上添加多态信息
@JsonTypeInfo(
    use = JsonTypeInfo.Id.NAME, // 使用逻辑名称作为类型标识
    include = JsonTypeInfo.As.PROPERTY, // 类型标识作为JSON的一个属性
    property = "type" // 类型标识属性的名称
)
@JsonSubTypes({
    @JsonSubTypes.Type(value = KafkaSourceConfig.class, name = "KAFKA"), // KafkaSourceConfig 对应 "KAFKA"
    @JsonSubTypes.Type(value = MysqlSourceConfig.class, name = "MYSQL")  // MysqlSourceConfig 对应 "MYSQL"
})
public abstract class SourceConfig {
  private long id;
  private String name;
  // ... 构造函数、Getter/Setter
}

// KafkaSourceConfig 和 MysqlSourceConfig 保持不变，但需确保有默认构造函数和对应的getter/setter
public class KafkaSourceConfig extends SourceConfig {
  private String topic;
  private String messageSchema;
  // ... 构造函数、Getter/Setter
}

public class MysqlSourceConfig extends SourceConfig {
  private String databaseName;
  private String tableName;
  // ... 构造函数、Getter/Setter
}

{
    "name": "mysql_to_bq_1",
    "sourceConfig": {
        "type": "MYSQL", // 新增的类型标识符
        "databaseName": "my_db",
        "tableName": "my_table"
    },
    "sinkConfig": {
        "type": "BIGQUERY", // 假设SinkConfig也有类似的多态处理
        "datasetName": "my_dataset"
    },
    "createdBy": "paul"
}

public class PipelineProcessor {

    public void processPipeline(Pipeline pipeline) {
        SourceConfig source = pipeline.getSourceConfig();

        if (source instanceof MysqlSourceConfig) {
            // 安全地转换为MysqlSourceConfig类型
            MysqlSourceConfig mysqlSource = (MysqlSourceConfig) source;
            System.out.println("Processing MySQL Source: Database - " + mysqlSource.getDatabaseName() + ", Table - " + mysqlSource.getTableName());
            // 执行与MySQL源相关的逻辑
        } else if (source instanceof KafkaSourceConfig) {
            // 安全地转换为KafkaSourceConfig类型
            KafkaSourceConfig kafkaSource = (KafkaSourceConfig) source;
            System.out.println("Processing Kafka Source: Topic - " + kafkaSource.getTopic() + ", Schema - " + kafkaSource.getMessageSchema());
            // 执行与Kafka源相关的逻辑
        } else {
            System.out.println("Unknown SourceConfig type: " + source.getClass().getName());
        }

        // ... 对sinkConfig进行类似处理
    }
}

// 不推荐的做法（对于多态场景）
public class Pipeline {
  // ...
  private KafkaSourceConfig kafkaSourceConfig;
  private MysqlSourceConfig mysqlSourceConfig; // 如果有多个源，需要多个字段
  // ...
}