groovy使用

安装

dnf install groovy

元编程意思应该是指「编写能改变语言语法特性或者运行时特性的程序」。

##groovy 调用shell命令

for (i in 0..2) { print ‘ho ‘}
println ‘Merry Groovy!’

0.upto(10) { print “$it “}

print(“\nI love you\n”)

println “svn help”.execute().getClass().name

str?.reverse() 如果str非空才执行

###
class Car {
def miles = 0
final year

Car(theYear) { year = theYear}

}

Car car = new Car(2008)

println “Year: $car.year”
println “Miles: $car.miles”
println “Setting miles”
car.miles = 25
println “Miles: $car.miles”

lst = [‘hello’]
lst << ‘there’
println lst

import static Math.random;
import static Math.random as rand;

str1 = ‘hello’
str1 = ‘Hello’
${ str1 == str2 }
${ str1.is(str2) }

##闭包

pickEven(10) {println it}
pickEven(10) { evenNumber -> printlen evenNumber }

/\d\w/ 与 “\d\w*” 等价
字符串前加~表示正则，匹配规则

Groovy 提供了一对操作符: =~ 和 ==~

pattern = ~”(G|g)roovy”
text = ‘Groovy is Hip’
if (text =~ pattern)
println “match”
else
println “no match”

if (text ==~ pattern)
println “match”
else
println “no match”
执行后结果:
match
no match

=~ 执行RegEx部分匹配，而==~执行RegEx精确匹配。因此，在前面的代码示例中，第一个模式匹配报告的是match,第二个是no match。

lst = [1,2,3,4,5,6,7]
lst.each { println it }

lst.collect { it 2 } 把迭代的值继续传给lst，相当于给每个值 2

##map的使用
langs = [‘c++’:’stroustrup’,’java’:’Gosling’,’Lisp’:’McCarthy’]

langs[‘c++’]
langs.’c++’

map 的引用

langs.each { entry ->
println “ $entry.key $entry.value”
}

langs.each { k,v ->
println “ $k $v”
}

http:///script
返回页面
http:///scriptText
return result/System.out

远程访问
$curl –data-urlencode “script=$(<./somescript.groovy)” http:///scriptText

pickEven(10) { evenNumber -> printlen evenNumber }