Jenkinsfile中字符串变量使用

Groovy 支持使用单引号或双引号声明一个字符串，例如：

def singlyQuoted = 'Hello'
def doublyQuoted = "World"

只有通过双引号才支持通过$获取，例如：

node('openjdk8') {
    def singlyQuoted = 'Hello'
    def doublyQuoted = "World"
    echo '${singlyQuoted} ${doublyQuoted}'
    echo '------------------------------'
    echo "${singlyQuoted} ${doublyQuoted}"
}

其结果是：

2022-02-14 09:45:39.130 | . [Pipeline] {
2022-02-14 09:45:39.168 | . [Pipeline] echo
2022-02-14 09:45:39.177 | . ${singlyQuoted} ${doublyQuoted}
2022-02-14 09:45:39.184 | . [Pipeline] echo
2022-02-14 09:45:39.187 | . ------------------------------
2022-02-14 09:45:39.198 | . [Pipeline] echo
2022-02-14 09:45:39.202 | . Hello World
2022-02-14 09:45:39.205 | . [Pipeline] }