NoSuchMethodException：java.time.LocalDateTime。<init>（）使用超级CSV读取CSV

138

斯图尔特·莱兰·科尔

我已经LocalDateTime使用Super CSV 编写了一个仅包含到CSV文件的实体，使用ICsvDozerBeanWriter读回该文件时遇到错误ICsvDozerBeanReader。我能够成功读取和写入Date对象，但LocalDateTime无法正常工作。

我已经添加了super-csv-java8依赖项，并且书写部分似乎工作正常。

我在这个Github存储库中创建了一个小型演示应用程序来复制问题。运行main（）方法，错误将输出到控制台。

这是我得到的例外：

2016-12-09 22:24:02.427 ERROR 50405 --- [           main] org.dozer.MappingProcessor               : Field mapping error -->
  MapId: null
  Type: null
  Source parent class: org.supercsv.io.dozer.CsvDozerBeanData
  Source field name: columns
  Source field type: class java.time.LocalDateTime
  Source field value: 2016-12-09T22:24:02.226
  Dest parent class: com.example.Entity
  Dest field name: dateTime
  Dest field type: java.time.LocalDateTime

org.dozer.MappingException: java.lang.NoSuchMethodException: java.time.LocalDateTime.<init>()
    at org.dozer.util.MappingUtils.throwMappingException(MappingUtils.java:82) ~[dozer-5.4.0.jar:na]
    at org.dozer.factory.ConstructionStrategies$ByConstructor.newInstance(ConstructionStrategies.java:261) ~[dozer-5.4.0.jar:na]
    at org.dozer.factory.ConstructionStrategies$ByConstructor.create(ConstructionStrategies.java:245) ~[dozer-5.4.0.jar:na]
    at org.dozer.factory.DestBeanCreator.create(DestBeanCreator.java:65) ~[dozer-5.4.0.jar:na]
    at org.dozer.MappingProcessor.mapCustomObject(MappingProcessor.java:489) [dozer-5.4.0.jar:na]
    at org.dozer.MappingProcessor.mapOrRecurseObject(MappingProcessor.java:446) [dozer-5.4.0.jar:na]
    at org.dozer.MappingProcessor.mapFromFieldMap(MappingProcessor.java:342) [dozer-5.4.0.jar:na]
    at org.dozer.MappingProcessor.mapField(MappingProcessor.java:288) [dozer-5.4.0.jar:na]
    at org.dozer.MappingProcessor.map(MappingProcessor.java:248) [dozer-5.4.0.jar:na]
    at org.dozer.MappingProcessor.map(MappingProcessor.java:197) [dozer-5.4.0.jar:na]
    at org.dozer.MappingProcessor.map(MappingProcessor.java:187) [dozer-5.4.0.jar:na]
    at org.dozer.MappingProcessor.map(MappingProcessor.java:124) [dozer-5.4.0.jar:na]
    at org.dozer.MappingProcessor.map(MappingProcessor.java:119) [dozer-5.4.0.jar:na]
    at org.dozer.DozerBeanMapper.map(DozerBeanMapper.java:120) [dozer-5.4.0.jar:na]
    at org.supercsv.io.dozer.CsvDozerBeanReader.readIntoBean(CsvDozerBeanReader.java:220) [super-csv-dozer-2.4.0.jar:na]
    at org.supercsv.io.dozer.CsvDozerBeanReader.read(CsvDozerBeanReader.java:160) [super-csv-dozer-2.4.0.jar:na]
    at com.example.DemoApplication.readEntities(DemoApplication.java:51) [classes/:na]
    at com.example.DemoApplication.main(DemoApplication.java:39) [classes/:na]
Caused by: java.lang.NoSuchMethodException: java.time.LocalDateTime.<init>()
    at java.lang.Class.getConstructor0(Class.java:3082) ~[na:1.8.0_66]
    at java.lang.Class.getDeclaredConstructor(Class.java:2178) ~[na:1.8.0_66]
    at org.dozer.factory.ConstructionStrategies$ByConstructor.newInstance(ConstructionStrategies.java:257) ~[dozer-5.4.0.jar:na]
    ... 16 common frames omitted

org.dozer.MappingException: java.lang.NoSuchMethodException: java.time.LocalDateTime.<init>()
    at org.dozer.util.MappingUtils.throwMappingException(MappingUtils.java:82)
    at org.dozer.factory.ConstructionStrategies$ByConstructor.newInstance(ConstructionStrategies.java:261)
    at org.dozer.factory.ConstructionStrategies$ByConstructor.create(ConstructionStrategies.java:245)
    at org.dozer.factory.DestBeanCreator.create(DestBeanCreator.java:65)
    at org.dozer.MappingProcessor.mapCustomObject(MappingProcessor.java:489)
    at org.dozer.MappingProcessor.mapOrRecurseObject(MappingProcessor.java:446)
    at org.dozer.MappingProcessor.mapFromFieldMap(MappingProcessor.java:342)
    at org.dozer.MappingProcessor.mapField(MappingProcessor.java:288)
    at org.dozer.MappingProcessor.map(MappingProcessor.java:248)
    at org.dozer.MappingProcessor.map(MappingProcessor.java:197)
    at org.dozer.MappingProcessor.map(MappingProcessor.java:187)
    at org.dozer.MappingProcessor.map(MappingProcessor.java:124)
    at org.dozer.MappingProcessor.map(MappingProcessor.java:119)
    at org.dozer.DozerBeanMapper.map(DozerBeanMapper.java:120)
    at org.supercsv.io.dozer.CsvDozerBeanReader.readIntoBean(CsvDozerBeanReader.java:220)
    at org.supercsv.io.dozer.CsvDozerBeanReader.read(CsvDozerBeanReader.java:160)
    at com.example.DemoApplication.readEntities(DemoApplication.java:51)
    at com.example.DemoApplication.main(DemoApplication.java:39)
Caused by: java.lang.NoSuchMethodException: java.time.LocalDateTime.<init>()
    at java.lang.Class.getConstructor0(Class.java:3082)
    at java.lang.Class.getDeclaredConstructor(Class.java:2178)
    at org.dozer.factory.ConstructionStrategies$ByConstructor.newInstance(ConstructionStrategies.java:257)

理想情况下，我想以yyyy-MM-dd格式将日期写入CSV文件，但一次只能执行一次！

詹姆斯·巴塞特

尽管Super CSV确实支持java.time.LocalDateTime通过其ParseLocalDateTime和FmtLocalDateTime单元处理器（super-csv-java8模块中均可用）进行读取和写入，但Dozer尝试实例化目标LocalDateTime对象而不是使用单元处理器的结果（Dozer的已知问题-它不存在）支持Java 8时间）。

2个解决方法是...

使用CsvBeanReader

CsvDozerBeanReader与交换CsvBeanReader。您将失去对深度/索引映射的支持，但从好的方面来说，它会更快。

在DozerBeanMapper中配置Java 8支持

如关于Dozer问题的讨论，有一个dozer-jdk8-support库可以解决此问题。

添加依赖项：

<dependency>
  <groupId>io.craftsman</groupId>
  <artifactId>dozer-jdk8-support</artifactId>
  <version>1.0.2</version>
</dependency>

配置一个DozerBeanMapper：

DozerBeanMapper beanMapper = new DozerBeanMapper();
beanMapper.setMappingFiles(Collections.singletonList("dozerJdk8Converters.xml"));

并将其提供给您CsvDozerBeanReader：

new CsvDozerBeanReader(reader, CsvPreference.STANDARD_PREFERENCE, beanMapper)

这有点样板，但是如果您确实需要推土机支持，这将使您正常运行。

ps我已经创建了PR以更新文档-仅列出了一个Java 8单元处理器，并且有堆！

本文收集自互联网，转载请注明来源。

如有侵权，请联系 [email protected] 删除。

编辑于 2020-10-19

我来说两句

0 条评论

登录后参与评论

上一篇：在熊猫python中按组的第n个十分位数划分的虚拟对象

TOP 榜单

文章