传递变量在groovy gstring中进行评估 [英] Passing variable to be evaluated in groovy gstring
问题描述
我想知道是否可以在gstring评估中将变量作为字符串进行评估。
最简单的例子就是一些类似于
$ b $ pre $ code def def ='person.lName'
def value = $ {var}
println(value)
person实例中lastName的值。作为最后的手段,我可以使用反射,但是想知道groovy应该有一些简单的东西,我不知道。
解决方案 你可以试一下:
def var = Eval.me('new Date()')
code>
代替您的示例中的第一行。
<一个href =http://groovy.codehaus.org/api/groovy/util/Eval.html =nofollow> Eval类记录在这里
(p)编辑
我猜(你的更新后的问题)你有个人变量,然后人们通过像 person.lName
这样的字符串,并且您想要返回该类的 lName
属性?
您可以使用GroovyShell来尝试这样的事情吗?
//假设我们有一个Person类
class Person {
String fName
String lName
}
//一个变量'person'存储在bi nd脚本
person = new Person(fName:'tim',lName:'yates')
//给出一个执行
的命令字符串def commandString =' person.lName'
GroovyShell shell = new GroovyShell(binding)
def result = shell.evaluate(commandString)
或者,使用直接字符串解析和属性访问
//假设我们有一个Person类
类Person {
String fName
String lName
}
//一个变量'person'存储在脚本
person = new Person(fName:'tim',lName:'yates')
//给出一个执行
的命令字符串def commandString ='person.lName '
//将命令字符串拆分为基于'。'的列表,并注入以空值开始
def result = commandString.split(/\./).inject(null ){curr,prop - >
//如果curr为null,则从绑定
返回属性//否则尝试从curr对象中获取给定属性
curr?。$ prop?:binding [道具]
}
I am wondering if I can pass variable to be evaluated as String inside gstring evaluation. simplest example will be some thing like
def var ='person.lName'
def value = "${var}"
println(value)
I am looking to get output the value of lastName in the person instance. As a last resort I can use reflection, but wondering there should be some thing simpler in groovy, that I am not aware of.
Can you try:
def var = Eval.me( 'new Date()' )
In place of the first line in your example.
The Eval class is documented here
edit
I am guessing (from your updated question) that you have a person variable, and then people are passing in a String like person.lName
, and you want to return the lName
property of that class?
Can you try something like this using GroovyShell?
// Assuming we have a Person class
class Person {
String fName
String lName
}
// And a variable 'person' stored in the binding of the script
person = new Person( fName:'tim', lName:'yates' )
// And given a command string to execute
def commandString = 'person.lName'
GroovyShell shell = new GroovyShell( binding )
def result = shell.evaluate( commandString )
Or this, using direct string parsing and property access
// Assuming we have a Person class
class Person {
String fName
String lName
}
// And a variable 'person' stored in the binding of the script
person = new Person( fName:'tim', lName:'yates' )
// And given a command string to execute
def commandString = 'person.lName'
// Split the command string into a list based on '.', and inject starting with null
def result = commandString.split( /\./ ).inject( null ) { curr, prop ->
// if curr is null, then return the property from the binding
// Otherwise try to get the given property from the curr object
curr?."$prop" ?: binding[ prop ]
}
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