在Spring Boot中以编程方式注册Spring Converter [英] Register Spring Converter Programmatically in Spring Boot

问题描述

我想以编程方式在Spring Boot项目中注册Spring Converter.在过去的Spring项目中，我已经用XML做到了这一点……

I want to register a Spring Converter in a Spring Boot project programmatically. In past Spring projects I've done it in XML like this...

<!-- Custom converters to allow automatic binding from Http requests parameters to objects -->
<!-- All converters are annotated w/@Component -->
<bean id="conversionService"
      class="org.springframework.context.support.ConversionServiceFactoryBean">
    <property name="converters">
        <list>
            <ref bean="stringToAssessmentConverter" />
        </list>
    </property>
</bean>

我正在尝试找出如何在Spring Boot的SpringBootServletInitializer中进行操作

I'm trying to figure out how to do in Spring Boot's SpringBootServletInitializer

更新:通过将StringToAssesssmentConverter作为参数传递给getConversionService，我取得了一些进步，但是现在我得到了StringToAssessmentConverter类的"No default constructor found"错误.我不确定为什么Spring没有看到@Autowired构造函数.

Update: I've made a little progress by passing the StringToAssessmentConverter as an argument to getConversionService, but now I'm getting a "No default constructor found" error for the StringToAssessmentConverter class. I'm not sure why Spring is not seeing the @Autowired constructor.

@SpringBootApplication
public class Application extends SpringBootServletInitializer {

    ...

    @Bean(name="conversionService")
    public ConversionServiceFactoryBean getConversionService(StringToAssessmentConverter stringToAssessmentConverter) {
        ConversionServiceFactoryBean bean = new ConversionServiceFactoryBean();

        Set<Converter> converters = new HashSet<>();

        converters.add(stringToAssessmentConverter);

        bean.setConverters(converters);
        return bean;
    }
}  

这是转换器的代码...

Here's the code for the Converter...

 @Component
 public class StringToAssessmentConverter implements Converter<String, Assessment> {

     private AssessmentService assessmentService;

     @Autowired
     public StringToAssessmentConverter(AssessmentService assessmentService) {
         this.assessmentService = assessmentService;
     }

     public Assessment convert(String source) {
         Long id = Long.valueOf(source);
         try {
             return assessmentService.find(id);
         } catch (SecurityException ex) {
             return null;
         }
     }
 }

完全错误

Failed to execute goal org.springframework.boot:spring-boot-maven-
plugin:1.3.2.RELEASE:run (default-cli) on project yrdstick: An exception 
occurred while running. null: InvocationTargetException: Error creating 
bean with name
'org.springframework.boot.context.properties.ConfigurationPropertiesBindingPo
stProcessor': Invocation of init method failed; nested exception is 
org.springframework.beans.factory.UnsatisfiedDependencyException: Error 
creating bean with name 'conversionService' defined in 
me.jpolete.yrdstick.Application: Unsatisfied dependency expressed through 
constructor argument with index 0 of type 
[me.jpolete.yrdstick.websupport.StringToAssessmentConverter]: : Error 
creating bean with name 'stringToAssessmentConverter' defined in file 
[/yrdstick/target/classes/me/jpolete/yrdstick/websupport
/StringToAssessmentConverter.class]: Instantiation of bean failed; nested 
exception is org.springframework.beans.BeanInstantiationException: Failed 
to instantiate 
[me.jpolete.yrdstick.websupport.StringToAssessmentConverter]: No default 
constructor found; nested exception is java.lang.NoSuchMethodException: 
me.jpolete.yrdstick.websupport.StringToAssessmentConverter.<init>(); 
nested exception is 
org.springframework.beans.factory.BeanCreationException: Error creating 
bean with name 'stringToAssessmentConverter' defined in file [/yrdstick
/dev/yrdstick/target/classes/me/jpolete/yrdstick/websupport
/StringToAssessmentConverter.class]: Instantiation of bean failed; nested 
exception is org.springframework.beans.BeanInstantiationException: Failed 
to instantiate 
[me.jpolete.yrdstick.websupport.StringToAssessmentConverter]: No default 
constructor found; nested exception is java.lang.NoSuchMethodException: 
me.jpolete.yrdstick.websupport.StringToAssessmentConverter.<init>()

推荐答案

答案是，您只需将转换器注释为@Component:

The answer is, you only need to anotate your converter as @Component:

这是我的转换器示例

import org.springframework.core.convert.converter.Converter;
@Component
public class DateUtilToDateSQLConverter implements Converter<java.util.Date, Date> {

    @Override
    public Date convert(java.util.Date source) {
        return new Date(source.getTime());
    }
}

然后，当Spring需要进行转换时，将调用该转换器.

Then when Spring needs to make convert, the converter is called.

我的Spring Boot版本:1.4.1

My Spring Boot Version: 1.4.1

这篇关于在Spring Boot中以编程方式注册Spring Converter的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！