How to inject a properties in a class with implements ImportBeanDefinitionRegistrar? - spring

Question

I wanna use the properties to set some swagger docket to spring but I cant get the properties when I implements ImportBeanDefinitionRegistrar and get an error
Caused by: java.lang.NoSuchMethodException:
com.github.sofior.swagger.SwaggerAutoConfiguration.<init>()
#Configuration
#EnableSwagger2
#EnableConfigurationProperties(SwaggerProperties.class)
public class SwaggerAutoConfiguration implements ImportBeanDefinitionRegistrar {
private final SwaggerProperties properties;
public SwaggerAutoConfiguration(SwaggerProperties properties) {
this.properties = properties;
}
#Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
System.out.println(properties);
properties.getDockets().forEach((docketName, docketProperties) -> {
BeanDefinitionBuilder builder = BeanDefinitionBuilder.rootBeanDefinition(Docket.class);
builder.addConstructorArgValue(docketProperties.getType());
builder.addConstructorArgValue(docketProperties.getType());
registry.registerBeanDefinition(docketName, builder.getRawBeanDefinition());
});
}
}

Answer 1

I think it is impossible to do this, because spring have two phase
1.bean registration
2.bean initialization and instantiation
SwaggerProperties can only be used after phase 2 when it is finished to instantiate, but registerBeanDefinitions is the phase 1

Answer 2

Basically you need to inject the properties to your class constructor.
So the configurations should be Autowired in order to work them.
#Autowired
public SwaggerAutoConfiguration(SwaggerProperties properties) {
this.properties = properties;
}
This should fix your "properties" is null issue.

Answer 3

the workaround of this question is to read a new properties during registerBeanDefinitions
EnableCustomSwagger
import org.springframework.context.annotation.Import;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
#Target(ElementType.TYPE)
#Retention(RetentionPolicy.RUNTIME)
#Documented
#Import(SwaggerAutoConfiguration.class)
public #interface EnableCustomSwagger {
String path() default "";
}
SwaggerAutoConfiguration
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.annotation.AnnotationAttributes;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.type.AnnotationMetadata;
public class SwaggerAutoConfiguration implements ImportBeanDefinitionRegistrar {
#Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
String clsName = EnableCustomSwagger.class.getName();
AnnotationAttributes attrs = AnnotationAttributes.fromMap(importingClassMetadata.getAnnotationAttributes(clsName, false));
if (!attrs.getString("path").equals("")) {
String path = attrs.getString("path");
ResourceLoader loader = new DefaultResourceLoader();
Resource resource = loader.getResource(path);
// you can get the value from your property files
}
//how can I get properties here,the properties is null
// properties.getDockets().forEach((docketName, docketProperties) -> {
// BeanDefinitionBuilder builder = BeanDefinitionBuilder.rootBeanDefinition(Docket.class);
// builder.addConstructorArgValue(docketProperties.getType());
// builder.addConstructorArgValue(docketProperties.getType());
// registry.registerBeanDefinition(docketName, builder.getRawBeanDefinition());
// });
}
}
Application
#SpringBootApplication
#EnableCustomSwagger(path="classpath:docklet.properties")
public class Application {
}

Answer 4

spring 2.x
import org.springframework.boot.context.properties.bind.Binder;
public class MultipleDataSourceComponentRegistrar implements ImportBeanDefinitionRegistrar, EnvironmentAware {
...
private Environment environment;
#Override
public void setEnvironment(Environment environment) {
this.environment = environment;
}
#Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
ConfigurationProperties annotationCp = MultipleDataSourceSetProperties.class.getAnnotation(ConfigurationProperties.class);
MultipleDataSourceSetProperties properties = Binder.get(environment).bind(annotationCp.prefix(), MultipleDataSourceSetProperties.class).get();
}
...