Apache StrSubstitutor使用方法

时间 2019-11-25

标签 apache strsubstitutor 使用方法栏目 Apache 繁體版

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Java中，对于格式化字符串，不管是String.format，仍是MessageFormat，都很难用。Velocity却是不错，可就是过重。今天给你们推荐Apache commons-lang中的StrSubstitutor。html

文档地址：https://commons.apache.org/proper/commons-lang/apidocs/org/apache/commons/lang3/text/StrSubstitutor.htmljava

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

1 <dependency>
2     <groupId>org.apache.commons</groupId>
3     <artifactId>commons-lang3</artifactId>
4     <version>3.4</version>
5 </dependency>

一、直接替换系统属性值api

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

二、使用Map替换字符串中的占位符ui

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.spa

三、StrSubstitutor会递归地替换变量，好比：code

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：yorm

四、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才能够。xml

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-1.8htm