我找到了一种访问credentials store in Jenkins的方法：

def getPassword = { username ->
    def creds = com.cloudbees.plugins.credentials.CredentialsProvider.lookupCredentials(
        com.cloudbees.plugins.credentials.common.StandardUsernamePasswordCredentials.class,
        jenkins.model.Jenkins.instance
    )

    def c = creds.findResult { it.username == username ? it : null }

    if ( c ) {
        println "found credential ${c.id} for username ${c.username}"

        def credentials_store = jenkins.model.Jenkins.instance.getExtensionList(
            'com.cloudbees.plugins.credentials.SystemCredentialsProvider'
            )[0].getStore()

         println "result: " + credentials_store
    } else {
      println "could not find credential for ${username}"
    }
}

getPassword("XYZ")

但现在我想得到的密码为适当的用户，我不能这样做...
我总是得到未知的方法等，如果我试图访问密码等。
这样做的原因是使用这个用户名/密码来调用git并从仓库中提取信息。
我总是得到这样的东西：

result: com.cloudbees.plugins.credentials.SystemCredentialsProvider$StoreImpl@1639eab2

更新

经过更多的实验（和Jeanne Boyarsky的提示），我发现我正在考虑编译。下面已经给了我用户的密码：

def getUserPassword = { username ->
    def creds = com.cloudbees.plugins.credentials.CredentialsProvider.lookupCredentials(
            com.cloudbees.plugins.credentials.common.StandardUsernamePasswordCredentials.class,
            jenkins.model.Jenkins.instance
            )

    def c = creds.findResult { it.username == username ? it : null }

    if ( c ) {
        return c.password
    } else {
        println "could not find credential for ${username}"
    }
}

此外，通过使用以下代码段，您可以迭代整个凭据存储区：

def credentials_store = jenkins.model.Jenkins.instance.getExtensionList(
        'com.cloudbees.plugins.credentials.SystemCredentialsProvider'
        )

println "credentials_store: ${credentials_store}"
println " Description: ${credentials_store.description}"
println " Target: ${credentials_store.target}"
credentials_store.each {  println "credentials_store.each: ${it}" }

credentials_store[0].credentials.each { it ->
    println "credentials: -> ${it}"
    if (it instanceof com.cloudbees.plugins.credentials.impl.UsernamePasswordCredentialsImpl) {
        println "XXX: username: ${it.username} password: ${it.password} description: ${it.description}"
    }
}

您将得到如下输出：

[(master)]:
credentials_store: [com.cloudbees.plugins.credentials.SystemCredentialsProvider@5a2822be]
 Description: [The descriptions...]
 Target: [com.cloudbees.plugins.credentials.SystemCredentialsProvider@5a2822be]
credentials_store.each: com.cloudbees.plugins.credentials.SystemCredentialsProvider@5a2822be
credentials: -> com.cloudbees.jenkins.plugins.sshcredentials.impl.BasicSSHUserPrivateKey@38357ca1
credentials: -> com.cloudbees.jenkins.plugins.sshcredentials.impl.BasicSSHUserPrivateKey@47cf7703
credentials: -> com.cloudbees.plugins.credentials.impl.UsernamePasswordCredentialsImpl@739abac5
XXX: username: User1 password: Password description: The description of the user.
credentials: -> com.cloudbees.plugins.credentials.impl.UsernamePasswordCredentialsImpl@884a53e6
XXX: username: User2 password: Password1 description: The description of the user1.
Result:   [com.cloudbees.jenkins.plugins.sshcredentials.impl.BasicSSHUserPrivateKey@38357ca1, com.cloudbees.jenkins.plugins.sshcredentials.impl.BasicSSHUserPrivateKey@47cf7703, com.cloudbees.plugins.credentials.impl.UsernamePasswordCredentialsImpl@739abac5, com.cloudbees.plugins.credentials.impl.UsernamePasswordCredentialsImpl@884a53e6]

因此，通过使用appropriate class in the instanceof clause，您可以选择您需要的内容。