Modelmapper無法將java.lang.String轉換為java.sql.Timestamp

main() {
StudentDataDto source= new StudentDataDto();
    studentDataDto.setCreatedAt("2022-01-20T11:12:46");
    StudentMetaDataEntity destination= modelMapper.map(studentDataDto,
        StudentMetaDataEntity.class);
}

StudentDataDto {
private String createdAt;
}

StudentMetaDataEntity {
private Timestamp createdAt; (java.sql.Timestamp)
}

例外訊息：

org.modelmapper.MappingException: ModelMapper mapping errors:

1) Converter org.modelmapper.internal.converter.DateConverter@2b08772d failed to convert java.lang.String to java.sql.Timestamp.
Caused by: org.modelmapper.MappingException: ModelMapper mapping errors:

1) String must be in JDBC format [yyyy-MM-dd HH:mm:ss.fffffffff] to create a java.sql.Timestamp

1 error
    at org.modelmapper.internal.Errors.toMappingException(Errors.java:258)
    at org.modelmapper.internal.converter.DateConverter.dateFor(DateConverter.java:125)
    at org.modelmapper.internal.converter.DateConverter.convert(DateConverter.java:70)
    at org.modelmapper.internal.converter.DateConverter.convert(DateConverter.java:53)
    at org.modelmapper.internal.MappingEngineImpl.convert(MappingEngineImpl.java:306)
    at org.modelmapper.internal.MappingEngineImpl.map(MappingEngineImpl.java:109)
    at org.modelmapper.internal.MappingEngineImpl.setDestinationValue(MappingEngineImpl.java:245)
    at org.modelmapper.internal.MappingEngineImpl.propertyMap(MappingEngineImpl.java:187)
    at org.modelmapper.internal.MappingEngineImpl.typeMap(MappingEngineImpl.java:151)
    at org.modelmapper.internal.MappingEngineImpl.map(MappingEngineImpl.java:114)
    at org.modelmapper.internal.MappingEngineImpl.map(MappingEngineImpl.java:71)
    at org.modelmapper.ModelMapper.mapInternal(ModelMapper.java:573)
    at org.modelmapper.ModelMapper.map(ModelMapper.java:406)
...

通過參考這個類似問題的答案，我了解到模型映射器的源代碼限制了時間戳字串格式。

我的問題：我是否可以保留我想要的時間戳格式并自定義我的模型映射器轉換器來解決例外，而不是將我的StudentDataDto屬性型別更改為？java.sql.Timestampyyyy-MM-dd'T'HH:mm:ss

uj5u.com熱心網友回復：

您只需要撰寫自己的轉換器并將其注冊到ModelMapper實體中。

1. 選項 1 - 更通用。如果您的日期字串將始終采用這種格式，您可以撰寫一個轉換器 from Stringto java.sql.Timestamp，因此即使使用其他 dto 也將始終應用它。

public class StringToTimestampConverter implements Converter<String, Timestamp> {

        private final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss");

        @Override
        public Timestamp convert(MappingContext<String, Timestamp> mappingContext) {
            String source = mappingContext.getSource();
            LocalDateTime dateTime = LocalDateTime.parse(source, this.formatter);
            return Timestamp.valueOf(dateTime);
        }
    }

基本上將字串轉換為LocaDateTimeusing DateTimeFormatter，然后轉換 using Timestamp.valueOf(LocalDateTime)。

2. 選項 2 - 更具體。如果您在應用程式中使用不同的格式，您可以制作StudentDataDto轉換StudentMetaDataEntity器

public class DtoToMetaConverter implements Converter<StudentDataDto, StudentMetaDataEntity> {

        @Override
        public StudentMetaDataEntity convert(MappingContext<StudentDataDto, StudentMetaDataEntity> mappingContext) {
            StudentDataDto source = mappingContext.getSource();
            StudentMetaDataEntity dest = new StudentMetaDataEntity();
            //Convert string to timestamp like in other example
            dest.setCreatedAt(...);
            return dest;
        }
    }

然后注冊轉換器并測驗它。

public class TimestampMain {

    public static void main(String[] args) {
        ModelMapper modelMapper = new ModelMapper();
        modelMapper.addConverter(new StringToTimestampConverter());

        StudentDataDto source = new StudentDataDto();
        source.setCreatedAt("2022-01-20T11:12:46");
        StudentMetaDataEntity destination = modelMapper.map(source, StudentMetaDataEntity.class);
        System.out.println(destination.getCreatedAt());
    }
}

此示例使用更通用的選項 1，但如果您需要選項 2，只需以類似方式注冊另一個轉換器。

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