当使用DynamoDBMapper进行对象映射时,如果出现错误消息“不支持;需要 @DynamoDBTyped 或 @DynamoDBTypeConverted”,则表示您需要在代码中使用@DynamoDBTyped或@DynamoDBTypeConverted注解来处理属性。
@DynamoDBTyped注解用于指示DynamoDBMapper属性是一个复杂类型,它将被序列化为DynamoDB的二进制格式。示例如下:
import com.amazonaws.services.dynamodbv2.datamodeling.*;
@DynamoDBTable(tableName = "your_table_name")
public class YourClass {
private ComplexType complexType;
@DynamoDBTyped(DynamoDBMapperFieldModel.DynamoDBAttributeType.M)
public ComplexType getComplexType() {
return complexType;
}
public void setComplexType(ComplexType complexType) {
this.complexType = complexType;
}
}
@DynamoDBTypeConverted注解用于指示DynamoDBMapper属性需要进行自定义类型转换。您可以创建一个实现DynamoDBTypeConverter接口的自定义类型转换器,并将其与属性相关联。示例如下:
import com.amazonaws.services.dynamodbv2.datamodeling.*;
@DynamoDBTable(tableName = "your_table_name")
public class YourClass {
private CustomType customType;
@DynamoDBTypeConverted(converter = CustomTypeConverter.class)
public CustomType getCustomType() {
return customType;
}
public void setCustomType(CustomType customType) {
this.customType = customType;
}
public static class CustomTypeConverter implements DynamoDBTypeConverter {
@Override
public String convert(CustomType object) {
// Convert CustomType to String for storage in DynamoDB
return object.toString();
}
@Override
public CustomType unconvert(String object) {
// Convert String from DynamoDB to CustomType
return CustomType.fromString(object);
}
}
}
请根据您的具体需求选择适合的注解和转换器类型。