您不能像这样更新环境变量。如果您正在使用EnvInject Plugin，您可以使用以下脚本来更新环境变量。

ef persistInfo(){

    def jenkins = Jenkins.instance
    def jobA = jenkins.getItemByFullName("$JOB_NAME")
    def prop2 = jobA.getProperty(org.jenkinsci.plugins.envinject.EnvInjectJobProperty);
    def con = prop2.getInfo().getPropertiesContent();

    def str = "NewValue"
      
    def prop = new EnvInjectJobPropertyInfo("", str , "", "", "", false)

    def propNew = new org.jenkinsci.plugins.envinject.EnvInjectJobProperty(prop)
    propNew.setOn(true)
    propNew.setKeepBuildVariables(true)
    propNew.setKeepJenkinsSystemVariables(true)
    jobA.addProperty(propNew)

    jobA.save();
}