(注意:我已经查看了类似的问题(例如this,其中问题是无法修改shell命令的输出)但我认为这种情况是截然不同的。)
我在Groovy中有一个使用参数的管道脚本(通过properties([parameters([...
)。当我将参数的值插入到双引号字符串中时,它无法对两个捕获的.equals()
检查(我的意思是“捕获和.trim()d!”)stdout(这是我的用例)甚至是简单的字符串字面量。
我可以使用.trim()
来解决这个问题,(尽管你可以看到,通过我回应它们并检查.length()
,没有任何东西给.trim()
),但我怀疑只有“有效”,因为它做了隐含的.toString()
--这也是一个成功的解决方法。
对我来说这看起来像个错误,但它确实是我第一次使用Groovy,所以也许我错过了一些东西 - 任何人都可以解释一下吗?
即使是一个简单的文字"foo"
failes(即"foo".equals("${params.foo_the_parameter}"
)。插值参数是其他类型的对象还是什么?
[编辑在得到@Matias Bjarland的答案后,我修改了下面的代码,使用println而不是带壳的回声,因为它使输出更简洁。他建议的解决方案反映在评论栏中。]
我的常规代码:
node() {
properties([
parameters([
string(
defaultValue: 'foo',
description: 'This is foo',
name: 'foo_the_parameter'
)
])
])
/* this is what I learned from the accepted answer
bob="${params.foo_the_parameter}"
println("class of interpolated param is ${bob.class}")
simple_foo="foo"
println("class of \"foo\" is ${simple_foo.class}")
*/
echoed_foo = sh(script:"echo 'foo'", returnStdout: true).trim()
println "echoed foo is [$echoed_foo], params foo is [${params.foo_the_parameter}]";
echo_foo_length = echoed_foo.length()
dqs_foo_length = "${params.foo_the_parameter}".length()
println "their lengths are: echo: [$echo_foo_length] and dqs: [$dqs_foo_length]";
if (echoed_foo.equals("${params.foo_the_parameter}")) {
println "SUCCESS they are equals()"
}
else {
println "FAIL they are not equals()" //this one fires
}
if (echoed_foo.equals("${params.foo_the_parameter}".trim())) {
println "SUCCESS they are equals() after the dqs gets a trim()" //this one fires
}
else {
println "FAIL they are not equals()after the dqs gets a trim()"
}
if (echoed_foo.equals("${params.foo_the_parameter}".toString())) {
println "SUCCESS they are equals() after the dqs gets a toString()" //this one fires
}
else {
println "FAIL they are not equals()after the dqs gets a toString()"
}
if ("foo".equals("${params.foo_the_parameter}")) {
println "SUCCESS at least a simple literal \"foo\" works"
}
else {
println "FAIL even a simple literal \"foo\" fails to be .equals() with the interpolated parameter" //this one fires
}
}
詹金斯输出:
Started by user Michael South
[Office365connector] No webhooks to notify
Obtained jenkins.groovy from git [email protected]:msouth/test_groovy_equals.git
Running in Durability level: MAX_SURVIVABILITY
[Pipeline] node
Running on subnet_mon_02 in /opt/jenkins/m1/workspace/field-analytics-org/test_string_equals
[Pipeline] {
[Pipeline] properties
[Pipeline] sh
[test_string_equals] Running shell script
+ echo foo
[Pipeline] echo
echoed foo is [foo], params foo is [foo]
[Pipeline] echo
their lengths are: echo: [3] and dqs: [3]
[Pipeline] echo
FAIL they are not equals()
[Pipeline] echo
SUCCESS they are equals() after the dqs gets a trim()
[Pipeline] echo
SUCCESS they are equals() after the dqs gets a toString()
[Pipeline] echo
FAIL even a simple literal "foo" fails to be .equals() with the interpolated parameter
[Pipeline] }
[Pipeline] // node
[Pipeline] End of Pipeline
[Office365connector] No webhooks to notify
Finished: SUCCESS
不确定这是否是你要击中的,但请考虑以下groovy代码:
def x = 'World'
def gstr = "Hello ${x}!"
def str = 'Hello World!'
println "class of gstr: ${gstr.class}"
println "class of str: ${str.class}"
println(gstr.equals(str))
println(gstr.toString().equals(str))
哪,运行时打印:
~> groovy solution.groovy
class of gstr: class org.codehaus.groovy.runtime.GStringImpl
class of str: class java.lang.String
false
true
~>
换句话说,字符串插值将导致groovy GString的实例,其不一定等于具有相同内容的字符串。使用.toString()
强制评估解决了这个特殊问题。
引用groovy documentation on string interpolation:
除了单引号和三引号字符串之外,任何Groovy表达式都可以在所有字符串文字中进行插值。插值是在对字符串求值时将字符串中的占位符替换为其值的行为。占位符表达式由$ {}包围,或者以$表示前缀。当GString被传递给以String为参数的方法时,通过调用该表达式上的toString(),将占位符内的表达式值计算为其字符串表示形式。
换句话说,您必须使用以下变体将GString实例分配给计划java String:
String str1 = gstr
def str2 = gstr as String
def str3 = (String) gstr
,调用一个接受String的方法(将GString强制转换为字符串)或调用gstr.toString()
强制转换。
希望有所帮助。
==
to compare strings在Java中,您使用String.equals()
,因为str1 == str2
没有达到您的期望:Java比较引用而不是值。
在Groovy中,你可以写str1 == str2
,它可以做你期望它做的事情。 Groovy使用String.compareTo()
比较值,并在结果为true
时返回0
。
GString g = "${'foo'}"
String s = "foo"
assert g == "foo" && s == "foo"
assert g instanceof GString && s instanceof String
assert !s.equals(g) && !g.equals(s)
assert g.compareTo(s) == 0 && s.compareTo(g) == 0
assert g == s && s == g