Question

美好的一天，我正在使用Spring 4.1.1.RELEASE开发Web应用程序。所有Spring配置都使用注释完成，除了一件事情之外它工作正常：

我在项目中有一个带有这些行的config.properties文件

cases.caseList.filter=test
cases.caseList.numberOfCasesPerPage=50

我有一个配置类

@Configuration
@ComponentScan(basePackageClasses={CaseConfig.class})
@PropertySource(value = "classpath:config.properties")
public class CasesModuleTestContextConfig { ... }

另一个班级

@Component
public class HttpRequestParamsToPaginationParams extends AbstractConverter<Map<String, String>, PaginationParams> {

    @Value("${cases.caseList.filter}")
    private String filter;

    @Value("${cases.caseList.numberOfCasesPerPage}")
    private Integer count;

    ...
}

属性“过滤器”的值是从属性资源中成功注入的。但我在财产'计数'上得到例外：

     13:58:45.274 [main] WARN  o.s.c.s.GenericApplicationContext - Exception encountered during context initialization - cancelling refresh attempt 
     org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'cz.pokus.core.test.config.ConversionServiceTestConfig': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private java.util.List cz.pokus.core.test.config.ConversionServiceTestConfig.converterList; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'httpRequestParamsToPaginationParams': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private java.lang.Integer cz.pokus.core.cases.converter.HttpRequestParamsToPaginationParams.count; nested exception is org.springframework.beans.TypeMismatchException: Failed to convert value of type 'java.lang.String' to required type 'java.lang.Integer'; nested exception is java.lang.NumberFormatException: For input string: "${cases.caseList.numberOfCasesPerPage}"
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334) ~[spring-beans-4.1.1.RELEASE.jar:4.1.1.RELEASE]
     ...
     Caused by: org.springframework.beans.TypeMismatchException: Failed to convert value of type 'java.lang.String' to required type 'java.lang.Integer'; nested exception is java.lang.NumberFormatException: For input string: "${cases.caseList.numberOfCasesPerPage}"
     ...
     Caused by: java.lang.NumberFormatException: For input string: "${cases.caseList.numberOfCasesPerPage}"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) ~[na:1.8.0_20]
at java.lang.Integer.parseInt(Integer.java:569) ~[na:1.8.0_20]
at java.lang.Integer.valueOf(Integer.java:766) ~[na:1.8.0_20]
     ...

当我将属性'count'的类型更改为String时，它开始工作：

        @Value("${cases.caseList.numberOfCasesPerPage}")
        private String count;

我相信Spring能够在使用@Value将属性资源的值注入Integer属性时将String转换为Integer。我找到了人们在没有抱怨的情况下使用的例子。你有任何想法，为什么它对我不起作用？

提前多多感谢。

Answer 1

如果您尝试使用@Value("")注释访问属性值，则应声明PropertySourcesPlaceholderConfigurer Bean。

尝试在配置类中添加以下代码段。

@Bean
public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
    return new PropertySourcesPlaceholderConfigurer();
}

如果您不想申报，请在课堂上自动装配org.springframework.core.env.Environment课程，以获取属性值。

@Autowired
private Environment environment;

public void readValues() {
    System.out.println("Some Message:"
            + environment.getProperty("<Property Name>")); 

}

Answer 2

就我而言，我忘记了注释中的 $ 符号

@Value("{cases.caseList.filter}")

代替

@Value("${cases.caseList.filter}")

@Value - ＆gt;无法转换类型＆＃39; java.lang.String＆＃39;的值要求的类型＆＃39; java.lang.Integer＆＃39;

2 个答案: