Spring Boot集成DynamoDB已声明@DynamoDBRangeKey仍报指定错误

我一眼就看出问题出在你同时使用了@Id注解和单独的@DynamoDBHashKey/@DynamoDBRangeKey注解上。在Spring Data DynamoDB体系里，@Id是用来标记复合主键的专属注解，当你给farmId加上@Id后，框架会默认它是唯一的单一主键，直接忽略你后续配置的@DynamoDBRangeKey。但你的数据表实际是分区键+排序键的复合结构，这就导致DynamoDB Mapper在加载数据时，找不到它预期中应该存在的范围键值，进而抛出报错。

快速修复方案 #

最直接的解决方式就是移除farmId上的@Id注解，让@DynamoDBHashKey和@DynamoDBRangeKey单独负责主键映射：

修改后的实体类代码：

@DynamoDBTable(tableName = "solar_farm_data") 
public class SolarFarmData { 
    // 移除这里的@Id注解
    private String farmId; 
    private Double ambientTemperature; 
    private Long createdMillis; 

    @DynamoDBHashKey(attributeName = "farm_id") 
    public String getFarmId() { return farmId; } 
    public void setFarmId(String farmId) { this.farmId = farmId; } 

    @DynamoDBRangeKey(attributeName = "created_millis") 
    public Long getCreatedMillis() { return createdMillis; } 
    public void setCreatedMillis(Long createdMillis) { this.createdMillis = createdMillis; } 

    @DynamoDBAttribute(attributeName = "ambient_temperature") 
    public Double getAmbientTemperature() { return ambientTemperature; } 
    public void setAmbientTemperature(Double ambientTemperature) { this.ambientTemperature = ambientTemperature; } 
}

进阶方案：用复合主键类管理（可选） #

如果你更习惯用@Id来统一管理复合主键，可以创建一个专门的主键类：

// 注意要实现Serializable接口
public class SolarFarmDataKey implements Serializable {
    private String farmId;
    private Long createdMillis;

    @DynamoDBHashKey(attributeName = "farm_id")
    public String getFarmId() { return farmId; }
    public void setFarmId(String farmId) { this.farmId = farmId; }

    @DynamoDBRangeKey(attributeName = "created_millis")
    public Long getCreatedMillis() { return createdMillis; }
    public void setCreatedMillis(Long createdMillis) { this.createdMillis = createdMillis; }
}

然后在实体类中引用这个主键类：

@DynamoDBTable(tableName = "solar_farm_data") 
public class SolarFarmData { 
    @Id
    private SolarFarmDataKey id; 
    private Double ambientTemperature; 

    // getter和setter方法
    public SolarFarmDataKey getId() { return id; }
    public void setId(SolarFarmDataKey id) { this.id = id; }

    @DynamoDBAttribute(attributeName = "ambient_temperature") 
    public Double getAmbientTemperature() { return ambientTemperature; } 
    public void setAmbientTemperature(Double ambientTemperature) { this.ambientTemperature = ambientTemperature; } 
}

不过针对你的场景，第一种直接移除@Id的方案更简单高效，能快速解决当前的报错问题。

内容的提问来源于stack exchange，提问作者samir kanta lenka