我遇到了链接中提到的相同问题: Mongo spring-data issue with java.util.Currency 我尝试了接受的答案。但它不起作用,我在行中收到 NullPointerException:
new CustomConversions(Arrays.asList(currencyToString, stringToCurrency));
所以我在新类中定义了转换器,如下所示:
@Component
public class CurrencyToStringConverter implements Converter<Currency,String>{
/* (non-Javadoc)
* @see com.fasterxml.jackson.databind.util.Converter#convert(java.lang.Object)
*/
@Override
public String convert(Currency arg0) {
System.out.println("***INSIDE CurrencyToStringConverter***"+arg0);
return arg0.getCurrencyCode();
}
}
和
@Component
public class StringToCurrencyConverter implements Converter<String,Currency>{
/* (non-Javadoc)
* @see org.springframework.core.convert.converter.Converter#convert(java.lang.Object)
*/
@Override
public Currency convert(String arg0) {
System.out.println("***INSIDE StringToCurrencyConverter***"+arg0);
return Currency.getInstance(arg0);
}
}
我在“customConversions()”中使用了它们,如下所示:
@Configuration
public class CustomMongoConfiguration extends AbstractMongoConfiguration {
@Autowired
private Environment env;
@Bean
@Override
public CustomConversions customConversions() {
System.out.println("***CUSTOM MONGO CONVERSIONS***");
List<Converter<?,?>> converters=new ArrayList<>();
converters.add(new CurrencyToStringConverter());
converters.add(new StringToCurrencyConverter());
return new CustomConversions(converters);
}
/* (non-Javadoc)
* @see org.springframework.data.mongodb.config.AbstractMongoConfiguration#getDatabaseName()
*/
@Override
protected String getDatabaseName() {
// TODO Auto-generated method stub
String prop = env.getProperty("spring.data.mongodb.database");
System.out.println("database naem:: "+prop);
return prop;
}
/* (non-Javadoc)
* @see org.springframework.data.mongodb.config.AbstractMongoConfiguration#mongo()
*/
@Override
@Bean
public Mongo mongo() throws Exception {
String prop = env.getProperty("spring.data.mongodb.host");
System.out.println("host naem:: "+prop);
return new MongoClient(prop);
}
}
当 spring-boot 应用程序启动时,我可以看到打印了以下语句:
System.out.println("***CUSTOM MONGO CONVERSIONS***");
System.out.println("database naem:: "+prop);
System.out.println("host naem:: "+prop);
但是当我尝试从 MongoDB 获取我的对象时,它从不调用 Converter 类中的“convert”方法,而且,我总是得到这个异常:
org.springframework.data.mapping.model.MappingException: No property null found on entity class java.util.Currency to bind constructor parameter to!
at org.springframework.data.mapping.model.PersistentEntityParameterValueProvider.getParameterValue(PersistentEntityParameterValueProvider.java:74)
at org.springframework.data.mapping.model.SpELExpressionParameterValueProvider.getParameterValue(SpELExpressionParameterValueProvider.java:63)
at org.springframework.data.convert.ReflectionEntityInstantiator.createInstance(ReflectionEntityInstantiator.java:71)
at org.springframework.data.convert.ClassGeneratingEntityInstantiator.createInstance(ClassGeneratingEntityInstantiator.java:83)
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:251)
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:231)
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.readValue(MappingMongoConverter.java:1186)
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.access$200(MappingMongoConverter.java:78)
at org.springframework.data.mongodb.core.convert.MappingMongoConverter$MongoDbPropertyValueProvider.getPropertyValue(MappingMongoConverter.java:1134)
at org.springframework.data.mongodb.core.convert.MappingMongoConverter.getValueInternal(MappingMongoConverter.java:870)
我也点击了这个链接:
Spring not using mongo custom converters
我按照链接中的建议,在类 CustomMongoConfiguration
中将 @Configuration 注释更改为 @Component。但它也不起作用。如果我使用@Component 注释,下面的语句会被打印多次。我不知道原因。
System.out.println("***CUSTOM MONGO CONVERSIONS***");
System.out.println("database naem:: "+prop);
System.out.println("host naem:: "+prop);
我正在使用 spring-boot 版本 1.3.2.RELEASE。
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.3.2.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
顺便说一下,我正在使用 application.properties
来配置 mongodb 属性,而不是任何基于 java 的配置:
spring.data.mongodb.host=localhost
spring.data.mongodb.password=
spring.data.mongodb.port=27017
spring.data.mongodb.repositories.enabled=true
spring.data.mongodb.database=abcde
过去三天我一直在努力解决这个问题。谁能帮帮我。
最佳答案
Currency
转换已通过 b7131b 添加从 1.9.0.M1
开始可用。
请将 @ReadingConverter
和 @WritingConverter
添加到您的 Converter
实现中,以便 CustomConversions
而不仅仅是底层ConversionService
知道这些。
关于mongodb - java.util.currency 的 spring-data-mongodb 问题,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/36017024/