Apache commons StringSubstitutor 替换占位符

Java中，对于格式化字符串，不论是String.format，还是MessageFormat，都很难用。Velocity倒是不错，可就是太重。今天给大家推荐Apache commons-lang中的StrSubstitutor。

文档地址：

https://commons.apache.org/proper/commons-lang/apidocs/org/apache/commons/lang3/text/StrSubstitutor.html

StrSubstitutor在apache的commons-lang3包中，要使用，请在pom.xml里加入如下依赖：

<dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-lang3</artifactId> <version>3.4</version> </dependency>

1、直接替换系统属性值

StrSubstitutor.replaceSystemProperties("You are running with java.version = ${java.version} and os.name = ${os.name}.");

2、使用Map替换字符串中的占位符

Map valuesMap = HashMap(); valuesMap.put("animal", "quick brown fox"); valuesMap.put("target", "lazy dog"); String templateString = "The ${animal} jumped over the ${target}."; StrSubstitutor sub = new StrSubstitutor(valuesMap); String resolvedString = sub.replace(templateString);

resolvedString的结果：The quick brown fox jumped over the lazy dog.

3、StrSubstitutor会递归地替换变量，比如：

Map<String, Object> params = Maps.newHashMap(); params.put("name", "${x}"); params.put("x", "y"); StrSubstitutor strSubstitutor = new StrSubstitutor(params); String hello2 = "${name}"; System.out.println(strSubstitutor.replace(hello2));

最后会输出：y

4、有时变量内还嵌套其它变量，这个StrSubstitutor也是支持的，不过要调用下setEnableSubstitutionInVariables才可以。

Map<String, Object> params = Maps.newHashMap(); params.put("jre-1.8", "java-version-1.8"); params.put("java.specification.version", "1.8"); StrSubstitutor strSubstitutor = new StrSubstitutor(params); strSubstitutor.setEnableSubstitutionInVariables(true); System.out.println(strSubstitutor.replace("${jre-${java.specification.version}}"));

输出：java-version-1.8

 

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来源于：

https://blog.csdn.net/mischeung/article/details/79753903