使用String參數的@Bean方法 - 異常

Question

這是一個帶有@Bean註釋的註釋驅動類。當我只有佔位符（）沒有任何字符串參數 - 它的工作原理，但我需要佔位符（字符串屬性）爲了動態更改位置。

@Configuration 
public class TestPlacehodler { 


    @Value("${string}") 
    public static String value; 

    @Bean 
    public static PropertySourcesPlaceholderConfigurer placeholder(String property) { 
     PropertySourcesPlaceholderConfigurer placeholder = new PropertySourcesPlaceholderConfigurer(); 
     placeholder.setIgnoreUnresolvablePlaceholders(true); 
     placeholder.setLocation(new ClassPathResource(property)); 

     return placeholder; 
    } 

    public static void main(String[] args) { 
     AbstractApplicationContext ctx = new AnnotationConfigApplicationContext(TestPlacehodler.class); 
     PropertySourcesPlaceholderConfigurer placeholder = placeholder("test.properties"); 
     placeholder.postProcessBeanFactory(ctx.getBeanFactory()); 
     System.out.println(value); 

    } 

我有這樣的例外：

Exception in thread "main" org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'placeholder' defined in class TestPlacehodler: Unsatisfied dependency expressed through constructor argument with index 0 of type [java.lang.String]: : No qualifying bean of type [java.lang.String] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [java.lang.String] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {} 
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:730) 
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:461) 
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1029) 
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:925) 
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:490) 
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:461) 
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295) 
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223) 
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292) 
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:198) 
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:657) 
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:461) 
    at org.springframework.context.annotation.AnnotationConfigApplicationContext.<init>(AnnotationConfigApplicationContext.java:73) 
    at TestPlacehodler.main(TestPlacehodler.java:26) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597) 
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120) 

    } 

Answer 1

你defenition public static PropertySourcesPlaceholderConfigurer placeholder(String property) 說春天來提供String類型的一些豆的方法。 您需要刪除String property參數並從其他位置獲取它的值。

此外，撥打PropertySourcesPlaceholderConfigurer placeholder = placeholder("test.properties");是錯誤的。方法將由Spring容器以自動方式執行（但目前不可能，因爲Spring不知道從哪裏獲取參數property）。