Apache StrSubstitutor使用方法

時間 2019-11-25

標籤 apache strsubstitutor 使用方法欄目 Apache 简体版

原文原文鏈接

Java中，對於格式化字符串，不管是String.format，仍是MessageFormat，都很難用。Velocity卻是不錯，可就是過重。今天給你們推薦Apache commons-lang中的StrSubstitutor。html

文檔地址：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，請在pom.xml里加入以下依賴：apache

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

一、直接替換系統屬性值api

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

二、使用Map替換字符串中的佔位符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的結果：The quick brown fox jumped over the lazy dog.spa

三、StrSubstitutor會遞歸地替換變量，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));

最後會輸出：yorm

四、有時變量內還嵌套其它變量，這個StrSubstitutor也是支持的，不過要調用下setEnableSubstitutionInVariables才能夠。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}}"));

輸出：java-version-1.8htm