Apache StrSubstitutor使用方法
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：
1 <dependency>
2 <groupId>org.apache.commons</groupId>
3 <artifactId>commons-lang3</artifactId>
4 <version>3.4</version>
5 </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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