[英]DynamoDB mapping List of Enum
使用Custom Marshall將枚舉類映射到DynamoDB對象非常簡單。 但是如何映射枚舉列表呢?
恩類
public enum Transport {
SMS,EMAIL,ALL;
}
DynamoDB映射器
public class Campaign{
private List<Transport> transport;
@DynamoDBAttribute(attributeName = "transport")
public List<Transport> getTransport() {
return transport;
}
public void setTransport(List<Transport> transport) {
this.transport = transport;
}
}
DynamoDBMarshaller已棄用。 請改用DynamoDBTypeConverter。
例:
恩類
public static enum ValidationFailure {
FRAUD, GENERAL_ERROR
}
DynamoDBTable類
@DynamoDBTable(tableName = "receipt")
public class Receipt {
private Long id;
private List<ValidationFailure> validation;
@DynamoDBHashKey(attributeName = "id")
public Long getId() {
return id;
}
@DynamoDBTypeConverted(converter = ValidationConverter.class)
public List<ValidationFailure> getValidation() {
return validation;
}
public void setId(Long id) {
this.id = id;
}
public void setValidation(List<ValidationFailure> validation) {
this.validation = validation;
}
}
轉換器:
public class ValidationConverter implements DynamoDBTypeConverter<List<String>, List<ValidationFailure>> {
@Override
public List<String> convert(List<ValidationFailure> object) {
List<String> result = new ArrayList<String>();
if (object != null) {
object.stream().forEach(e -> result.add(e.name()));
}
return result;
}
@Override
public List<ValidationFailure> unconvert(List<String> object) {
List<ValidationFailure> result = new ArrayList<ValidationFailure>();
if (object != null) {
object.stream().forEach(e -> result.add(ValidationFailure.valueOf(e)));
}
return result;
}
}
它對我有用,我用過Set
@DynamoDBTyped(DynamoDBMapperFieldModel.DynamoDBAttributeType.SS)
var roles: MutableSet<Employee.Role>? = null
我認為相同的方法適用於List with DynamoDBAttributeType.L
我自己找到了答案。 我創建了一個如下所示的自定義馬歇爾。
public class TransportMarshaller implements DynamoDBMarshaller<List<Transport>> {
@Override
public String marshall(List<Transport> transports) {
List<String>transportMap=new ArrayList<>();
for(Transport transport:transports){
transportMap.add(transport.name());
}
return transportMap.toString().replaceAll("\\[|\\]", "");//Save as comma separate value for the purpose of easiness to unmarshall
}
@Override
public List<Transport> unmarshall(Class<List<Transport>> aClass, String s) {
List<String>map= Arrays.asList(s.split("\\s*,\\s*")); //split from comma and parse to List
List<Transport>transports=new ArrayList<>();
for (String st:map){
transports.add(Transport.valueOf(st));
}
return transports;
}
}
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