本文链接：https://blog.csdn.net/feather_wch/article/details/131618022

/***===============================* 闭包* 1、闭包是什么？匿名内联函数，也称为闭包* 2、闭包是函数内部和外部的桥梁** 闭包一般不会直接使用，而是作为参数传入* 闭包具有的关键变量：*  1. this*  2. owner*  3. delegate*  4. 闭包的委托策略*=================================*/def closure={println("hello")
}
closure() // 方法1
closure.call()// 参数闭包
def closeureParam={String name, int age->println("name:$name:age:$age")
}
closeureParam.call("wch", 20)// 内置参数 it
def closureIt={println "hello it=$it"return it
}
closureIt.call("wch")
// 返回值
def result = closureIt.call("feather")
println(result)// 基本数据类型API 1.upto(n, xxx) 1~n
int n1 = fab(3)
int fab(int number){int result = 1;1.upto(number, { num-> result *= num})return result
}
println(n1)// 基本数据类型API n.downto(1, xxx) n~1
int fab2(int n){int result = 1n.downto(1){result *= it}return result
}
int n2 = fab2(5)
println(n2)// 基本数据类型API 5.times 1,2,3,4  < size(5)
int sum(int n){int result = 0n.times {result += it}return result
}
println(sum(5))// String each
String strEach = "math: 2 + 3 = 5"
strEach.each { s->if(s.isNumber())println(s)// 每个字符复重复2个s.multiply(2)
}// String find查找符合条件的第一个字符
println strEach.find{it.isNumber()
}
// String findAll 符合的所有字符
def list = strEach.findAll{it.isNumber()
}
println(list.toListString())// String any 查找是否有符合条件的字符
def resultAny = strEach.any {it.isNumber()
}
println(resultAny)// every 是否所有的字符都符合条件
def resultEvery = strEach.every {it.isNumber()
}
println(resultEvery)// collect 所有的东西都操作, 比如都转化为大写
def listCollection = strEach.collect{it.toUpperCase()
}
println(listCollection.toListString())def scriptClosure = {println(this) // 闭包定义处的类println(owner) // 闭包定义处的类或者对象println(delegate) // 任意对象，默认是owner指向的对象
}
scriptClosure.call() // 没有任何区别，在普通类或者对象中也没有任何区别// 多用于架构设计
def nestClosure = {def innerClosure = {println("innerClosure=====================")println(this) // innerClosure对象println(owner) // nestClosure对象println(delegate) // nestClosure对象}innerClosure.call()
}
nestClosure.call()HelloWorld h = new HelloWorld()
def nestClosureD = {def innerClosureD = {println("修改delegate=====================")println(this) // innerClosureD对象println(owner) // nestClosureD对象println(delegate) // HelloWorld对象}innerClosureD.delegate = h // 修改delegateinnerClosureD.call()
}
nestClosureD.call()/**** 闭包的委托策略*/
class Student{String namedef desc = {"My name is $name"}String toString(){desc.call()}
}
def student = new Student(name:"wch") // 指定参数，进行构造
println student.toString()class Teacher{String name
}
def teacher = new Teacher(name:"derry")
student.desc.delegate = teacher // 代理，是否生效取决于委托策略
student.desc.resolveStrategy = groovy.lang.Closure.DELEGATE_FIRST // 委托策略println student.toString()