context:propertyPlaceholder
Activates replacement of ${...} placeholders by registering a PropertySourcesPlaceholderConfigurer within the application context. Properties will be resolved against the specified properties file or Properties object -- so called "local properties", if any, and against the Spring Environment's current set of PropertySources. Note that as of Spring 3.1 the system-properties-mode attribute has been removed in favor of the more flexible PropertySources mechanism. However, Spring 3.1-based applications may continue to use the 3.0 (and older) versions of the spring-context schema in order to preserve system-properties-mode behavior. In this case, the traditional PropertyPlaceholderConfigurer component will be registered instead of the new PropertySourcesPlaceholderConfigurer. See ConfigurableEnvironment javadoc for more information on using.
方式一:
<context:property-placeholder location="classpath:foo.properties"/>
@Component public class FooProperties { public static String fooName; @Autowired public void setFooName( @Value("${foo.name}") String fooName) { FooProperties.fooName = fooName; } }
方式二:
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="locations"> <value>classpath:foo.properties</value> </property> </bean>
@Component public class FooProperties { public static String fooName; @Autowired public void setFooName( @Value("${foo.name}") String fooName) { FooProperties.fooName = fooName; } }
方式三:
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="properties"> <value> foo.name=aaa foo.age=12 </value> </property> </bean>
@Component public class FooProperties { public static String fooName; @Autowired public void setFooName( @Value("${foo.name}") String fooName) { FooProperties.fooName = fooName; } }
方式四:
new PropertyPlaceholderConfigurer() { @Override protected void processProperties(ConfigurableListableBeanFactory beanFactoryToProcess, Properties props) throws BeansException { // TODO Auto-generated method stub super.processProperties(beanFactoryToProcess, props); } }
重写默认placeholder 配置器
注: @Value 通过实例方法给静态变量注入值的时候需要配合 @Autowired 使用
@Value 可以直接为实例变量注入值 ${...} or "#{...['XXX']}
@Value("${...}") 与 @Value("#{...['XXX']} 各有优势,需视情况使用