java - Spring-Data-MongoDB:使用自定义转换器升级到 2.0.7 后无法从类型转换

Question

我今天刚刚升级到 Spring Boot 2.0.2，同时升级到 Spring-Data-MongoDB 2.0.7。

我有以下实体:

@Document
@Data
public class User {
private String username;
private String password;
private List<String> authorities;

    public User(String username, String password, List<String> authorities) {
        this.username = username;
        this.password = password;
        this.authorities = authorities;
    }
}

在我的测试中，我使用以下方法插入了一个新用户:

mongoTemplate.save(new User("testuser", "$2a$04$OuKj.lXzPxlwgr2Jy28E4ehHuxnVZ7BuL46qX9fd6vAijcDN6UeHe", Collections.singletonList("user")));

这在使用 Spring Boot 2.0.1(分别为 Spring-Data-MongoDB 2.0.6)时非常有效。使用升级后的 Spring-Data-MongoDB 版本，出现以下错误:

org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.String] to type [java.time.ZonedDateTime] for value 'testuser'; nested exception is java.time.format.DateTimeParseException: Text 'testuser' could not be parsed at index 0

    at org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:46)
    at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:191)
    at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:174)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.getPotentiallyConvertedSimpleWrite(MappingMongoConverter.java:849)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.writeSimpleInternal(MappingMongoConverter.java:829)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.writeProperties(MappingMongoConverter.java:488)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.writeInternal(MappingMongoConverter.java:462)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.writeInternal(MappingMongoConverter.java:436)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.write(MappingMongoConverter.java:391)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.write(MappingMongoConverter.java:86)
    at org.springframework.data.mongodb.core.MongoTemplate.toDocument(MongoTemplate.java:1070)
    at org.springframework.data.mongodb.core.MongoTemplate.doSave(MongoTemplate.java:1253)
    at org.springframework.data.mongodb.core.MongoTemplate.save(MongoTemplate.java:1201)
    at org.springframework.data.mongodb.core.MongoTemplate.save(MongoTemplate.java:1185)
....
Caused by: java.time.format.DateTimeParseException: Text 'testuser' could not be parsed at index 0
    at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1949)
    at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851)
    at java.time.ZonedDateTime.parse(ZonedDateTime.java:597)
    at at.riag.scanpay.config.MongoConfig$StringToZonedDateTime.convert(MongoConfig.java:34)
    at at.riag.scanpay.config.MongoConfig$StringToZonedDateTime.convert(MongoConfig.java:28)
    at org.springframework.core.convert.support.GenericConversionService$ConverterAdapter.convert(GenericConversionService.java:385)
    at org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:40)
    ... 71 more

看起来，它想要将 username 转换为 ZonedDateTime。问题可能出在我的 MongoConfig 上，我在其中为 ZonedDateTime 设置了自定义转换器:

@Configuration
public class MongoConfig {

    private static final DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ISO_ZONED_DATE_TIME;

    @Bean
    public MongoCustomConversions customConversions(){
        List<Converter<?,?>> converters = new ArrayList<>();
        converters.add(ZonedDateTimeToStringConverter.INSTANCE);
        converters.add(StringToZonedDateTime.INSTANCE);
        return new MongoCustomConversions(converters);
    }

    enum StringToZonedDateTime implements Converter<String, ZonedDateTime> {

        INSTANCE;

        @Override
        public ZonedDateTime convert(String source) {
            return ZonedDateTime.parse(source, dateTimeFormatter);
        }
    }

    enum ZonedDateTimeToStringConverter implements Converter<ZonedDateTime, String> {

        INSTANCE;

        @Override
        public String convert(ZonedDateTime source) {
            return dateTimeFormatter.format(source);
        }
    }
}

当然，这些转换器不应该用于纯字符串，但似乎在使用新的 Spring Data MongoDB 版本时会触发它。谁能指出我的代码存在的问题，或者最新版本是否有问题？

提前致谢!

Answer 1

Spring Data MongoDB 2.0.7 将 ZonedDateType 视为简单类型。您需要通过添加 @ReadingConverter/@WritingConverter 来消除转换器为读写转换器的歧义。

在您上面的安排中，框架尝试将所有 String 值转换为 ZonedDateTime。相反，您想在 MongoDB 中将 ZonedDateTime 对象表示为 String。因此，将 @WritingConverter 添加到 ZonedDateTimeToStringConverter 并将 @ReadingConverter 添加到另一个可以解决您的问题。