如何在Spring @Value批注中正确指定默认值? [英] How to correctly specify a default value in the Spring @Value annotation?
问题描述
最初,我具有以下规格:
Initially, I have the following spec:
@Value("#{props.isFPL}")
private boolean isFPL=false;
这可以正确地从属性文件中获取值:
This works fine correctly getting the value from the property file:
isFPL = true
但是,以下具有默认值的表达式会导致错误:
However, the following expression with default results in the error:
@Value("#{props.isFPL:false}")
private boolean isFPL=false;
表达式解析失败;嵌套的异常是org.springframework.expression.spel.SpelParseException:EL1041E:(pos 28):解析有效的表达式后,表达式中还有更多数据:'colon(:)'
我也尝试使用$代替#.
I also tried to use $ instead of #.
@Value("${props.isFPL:true}")
private boolean isFPL=false;
然后注释中的默认值可以正常工作,但是我没有从属性文件中获取正确的值:
Then the default value in annotation works fine but I did not get the correct value from the Properties file:
推荐答案
尝试使用$
如下:
@Value("${props.isFPL:true}")
private boolean isFPL=false;
还要确保将ignore-resource-no-found
设置为 true ,这样,如果缺少属性文件,则将采用 default 值.
Also make sure you set the ignore-resource-no-found
to true so that if the property file is missing, the default value will be taken.
如果使用基于XML的配置,请在上下文文件中放置以下内容:
Place the following in the context file if using XML based configuration:
<context:property-placeholder ignore-resource-not-found="true"/>
如果使用Java配置:
If using Java configurations:
@Bean
public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
PropertySourcesPlaceholderConfigurer p = new PropertySourcesPlaceholderConfigurer();
p.setIgnoreResourceNotFound(true);
return p;
}
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