spring - 如何为 Joda Period 注入(inject)配置值

Question

如何使用 @Value 注释在我的 spring bean 中配置 Joda-Time Period 字段？

例如。给定以下组件类:

@Component
public class MyService {

  @Value("${myapp.period:P1D}")
  private Period periodField;
...
}

我想使用标准 ISO8601 格式来定义属性文件中的句点。

我收到此错误:

Caused by: java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [org.joda.time.Period]: no matching editors or conversion strategy found
    at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:302)
    at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:125)
    at org.springframework.beans.TypeConverterSupport.doConvert(TypeConverterSupport.java:61)
    ... 35 more

Answer 1

你可以做的是register a Spring ConversionService bean 和implement a proper converter .

@Bean
public ConversionServiceFactoryBean conversionService() {
    ConversionServiceFactoryBean conversionServiceFactoryBean = new ConversionServiceFactoryBean();
    Set<Converter<?, ?>> myConverters = new HashSet<>();
    myConverters.add(new StringToPeriodConverter());
    conversionServiceFactoryBean.setConverters(myConverters);
    return conversionServiceFactoryBean;
}

public class StringToPeriodConverter implements Converter<String, Period> {

    @Override
    public Period convert(String source) {
        return Period.parse(source);
    }
}