Java 属性：如何转义 #（哈希）

Question

如何转义 Java 属性文件中的井号 ( # )。

我们有一个使用 Java 属性文件的国际化框架。

有一个名为 number 的列，我们希望它的标题是# 。 这个 ...

number=#

...不起作用。

Answer 1

这个应该没有任何转义字符：

number=#

刚刚使用代码做了一个小测试....

prop.load(new FileInputStream ("./res/app.properties"));
System.out.println("Property: " +prop.getProperty("Number"));

...和属性文件（注意大写/小写）：

Number=#
Text=test

结果：

Property: #

所以请检查您的拼写，大小写或进一步处理。

查看这个或那个 （链接Java文档）以获取更多信息。

ps ：虽然不应该要求你也可以尝试Unicode序列： \# 。

干杯!

Answer 2

在以下情况下（我不工作），在查看如何正确逃生时，我发现了这个问题：

zendesk.ticket.subject.prefix=#{{ticket.id}}

在这种情况下，它需要转义，否则会发生以下异常：

Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'createTicketService' defined in file [/Users/***]: Unsatisfied dependency expressed through constructor parameter 6; nested exception is org.springframework.beans.factory.BeanExpressionException: Expression parsing failed; nested exception is org.springframework.expression.spel.SpelEvaluationException: EL1008E: Property or field 'ticket' cannot be found on object of type 'org.springframework.beans.factory.config.BeanExpressionContext' - maybe not public?
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:749)
    at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:189)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1193)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1095)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:835)
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741)
    ... 64 common frames omitted
Caused by: org.springframework.beans.factory.BeanExpressionException: Expression parsing failed; nested exception is org.springframework.expression.spel.SpelEvaluationException: EL1008E: Property or field 'ticket' cannot be found on object of type 'org.springframework.beans.factory.config.BeanExpressionContext' - maybe not public?
    at org.springframework.context.expression.StandardBeanExpressionResolver.evaluate(StandardBeanExpressionResolver.java:164)
    at org.springframework.beans.factory.support.AbstractBeanFactory.evaluateBeanDefinitionString(AbstractBeanFactory.java:1448)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1088)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:835)
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741)
    ... 78 common frames omitted
Caused by: org.springframework.expression.spel.SpelEvaluationException: EL1008E: Property or field 'ticket' cannot be found on object of type 'org.springframework.beans.factory.config.BeanExpressionContext' - maybe not public?
    at org.springframework.expression.spel.ast.PropertyOrFieldReference.readProperty(PropertyOrFieldReference.java:226)
    at org.springframework.expression.spel.ast.PropertyOrFieldReference.getValueInternal(PropertyOrFieldReference.java:94)
    at org.springframework.expression.spel.ast.PropertyOrFieldReference.getValueInternal(PropertyOrFieldReference.java:81)
    at org.springframework.expression.spel.ast.CompoundExpression.getValueRef(CompoundExpression.java:51)
    at org.springframework.expression.spel.ast.CompoundExpression.getValueInternal(CompoundExpression.java:87)
    at org.springframework.expression.spel.ast.SpelNodeImpl.getValue(SpelNodeImpl.java:120)
    at org.springframework.expression.spel.ast.InlineList.getValueInternal(InlineList.java:95)
    at org.springframework.expression.spel.ast.SpelNodeImpl.getTypedValue(SpelNodeImpl.java:131)
    at org.springframework.expression.spel.standard.SpelExpression.getValue(SpelExpression.java:297)
    at org.springframework.expression.common.CompositeStringExpression.getValue(CompositeStringExpression.java:105)
    at org.springframework.expression.common.CompositeStringExpression.getValue(CompositeStringExpression.java:42)
    at org.springframework.context.expression.StandardBeanExpressionResolver.evaluate(StandardBeanExpressionResolver.java:161)
    ... 83 common frames omitted

/ a解决方案是使用#{'#'}结果为（WORKS）：

zendesk.ticket.subject.prefix=#{'#'}{{ticket.id}}

Answer 3

哈希 ( # ) 在属性文件中使用\\字符进行转义。 例如，要将键#foo映射到值#bar ，您可以编写：

\#foo=\#bar

它适用于键和值，尽管（如其他答案中所暗示的）它不是值的严格要求。

Answer 4

由于Java中的默认转义字符是'\\'尝试使用它来转义哈希。