Java 屬性：如何轉義 #（哈希）

Question

如何轉義 Java 屬性文件中的井號 ( # )。

我們有一個使用 Java 屬性文件的國際化框架。

有一個名為 number 的列，我們希望它的標題是# 。 這個 ...

number=#

...不起作用。

Answer 1

這個應該沒有任何轉義字符：

number=#

剛剛使用代碼做了一個小測試....

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

...和屬性文件（注意大寫/小寫）：

Number=#
Text=test

結果：

Property: #

所以請檢查您的拼寫，大小寫或進一步處理。

查看這個或那個 （鏈接Java文檔）以獲取更多信息。

ps ：雖然不應該要求你也可以嘗試Unicode序列： \# 。

干杯!

Answer 2

在以下情況下（我不工作），在查看如何正確逃生時，我發現了這個問題：

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

在這種情況下，它需要轉義，否則會發生以下異常：

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解決方案是使用#{'#'}結果為（WORKS）：

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

Answer 3

哈希 ( # ) 在屬性文件中使用\\字符進行轉義。 例如，要將鍵#foo映射到值#bar ，您可以編寫：

\#foo=\#bar

它適用於鍵和值，盡管（如其他答案中所暗示的）它不是值的嚴格要求。

Answer 4

由於Java中的默認轉義字符是'\\'嘗試使用它來轉義哈希。