Groovy基础总结

这里就先整理一下基础的groovy东西

1 字符串类型的方法:

def firstname='Kate'
def surname='Bush'
//打印字符串的连接
println firstname*2

def fullname="$firstname $surname"
println fullname
println fullname-firstname
//凑足15个字符,不够就在左边补充空格
println fullname.padLeft(15)  

//关于字符串的截取
println fullname[0..3]
println fullname[-4..-1]
//下面的方式比较特别,取第5个字符,以及3,2,1位置字符连接起来
assert fullname[5,3..1]=='Beta'

ff='aaaabbccadvbasd'
lines=ff.split('a')
//下面assert在后面表达式为false情况下抛出异常
assert lines.size()==7

//注意字符串中的特殊字符
def plain='nrtbf$'
assert plain.size()==7

//关于字符串的闭包(注意下面的括号的使用方法!)
fullname="${-> firstname} $surname"
println fullname
firstname = 'li'
surname='shuiqing'
println fullname

//关于字符串的运算符
fullname = fullname -'qing'-'l'+' hello world'
assert fullname=='i Bush hello world'

//字符串替换
string = 'hippopotamus'
assert string.replace('ppopotam','bisc') == 'hibiscus'

//字符串反转,转换为list
assert'apple'.toList() == ['a','p','l','e']

//下面把字符串里面去掉重复数字,并排序.
string = "an apple a day"
assert string.toList().unique().sort().join() == ' adelnpy'

//下面方法取出得到字符串里面的各个单词,并进行反转
string = 'Yoda said,"can you see this?"'
revwords= string.split(' ').toList().reverse().join(' ')
assert revwords== 'this?" see you "can said,Yoda'
println revwords

//对数组进行筛选,找出反转之后还等于原来字符串并且长度大于5的字符串
words = ['bob','alpha','rotator','omega','reviver']
bigPalindromes= words.findAll{w-> w == w.reverse() && w.size() > 5}
assert bigPalindromes== ['rotator','reviver']
println bigPalindromes

数字函数：

def x=3
def y=4
println x+y
println x.plus(y)                
println x instanceof Integer   //输出true

def a=2/3
//进行小数的取三位小数运算.
def b = a.setScale(3,BigDecimal.ROUND_HALF_UP)
assert b.toString() == '0.667'

//进行不等于的比较
println 4<=>3     //输出1
   4！=3
  
println 4**3      //4的3次方,等于4.power(3)
println 4/3       //输出1.3333333333,等于4.div(3)
println 8.intdiv(3)     //输出1
println 8%3          //取余,等于8.mod(3)

import static java.util.Calendar.getInstance as now
import org.codehaus.groovy.runtime.TimeCategory
import java.text.SimpleDateFormat

def date = new Date()+1
println date

input = '1998-06-03'
df1 = new SimpleDateFormat("yyyy-MM-dd")
date = df1.parse(input)
df2 = new SimpleDateFormat("MMM/dd/yyyy")
println 'Date was '+df2.format(date)

println now().time

println  df1.format(now().time)

//进行时间的计算
use(TimeCategory){
    date3 =  new Date()+1.year+3.hours-2.days
    println df1.format(date3)
}

/*
Tue Apr 10 14:59:33 CST 2012
Date was 六月/03/1998
Mon Apr 09 14:59:33 CST 2012
2012-04-09
2013-04-07
*/

操作符重载：

//下面演示对字符串实现了操作符++的重载.++对应的方法名是next
 for ( i='a';i<'d';i++)
   print i +","
 
 println ''
   
 for( i in 'a'..'d')
  print i+","
  
  //下面演示的对于集合，重载了操作符<<,对应的方法名是leftShift()
  lst = ['hello']
  lst << 'there'
  println lst
  
  //下面演示对一个自定义类实现的+的重载。
  class ComplexNumber{
      def real,imaginary
      
      def plus(other){
          new ComplexNumber(real:real+other.real,imaginary:imaginary+other.imaginary)
      }
      
      String toString(){
          "$real ${imaginary>0 ? '+':''}${imaginary}i"
      }
  }
  
  c1 = new ComplexNumber(real:1,imaginary:2)
  c2 = new ComplexNumber(real:4,imaginary:-31)
  
  println c1+c2

操作数据库：

import groovy.sql.Sql
def testYear = '2011'
//下面的Driver类找不到！修改配置文件就可以了。
def sql = Sql.newInstance("jdbc:mysql://localhost:3306/dwz","root","123456","com.mysql.jdbc.Driver")
println '数据库名:'+sql.connection.catalog

   
sql.execute("delete from testtable where name like ? or name like ? or name like ?",['ls%','lish%','%dataSet%']) 

println '插入我的数据之前，数据库：'
sql.eachRow("select * from testtable"){
    println "id = ${it.id}   year = ${it.name}  "+it.name
}
println '--------------------------------------'
wid = 123
wname = 'lishuiqing'
//下面必须使用双引号！
sql.execute("insert into testtable(id,name) values (${wid},${wname})") 

sql.execute("update testtable set name =? where name = ?",['lsq','lishuiqing'])

//下面使用预定义参数的查询语句
sql.eachRow("select * from testtable where name like ?",["%a%"]){
    println "id = ${it.id}   year = ${it.name}  "+it.name
}
println '--------------------------------------'

println '下面练习使用dataset'
testtable = sql.dataSet('testtable')

/*def anycity = testtable.findAll{ it.id>1 }
anycity.each{
    println 1
}*/
 
2.times{
    testtable.add(id:it,name:'使用dataSet添加'+it)
}

println "testtable.getSql():"+testtable.getSql()
println '总行数:'+testtable.rows().size()
 

num = 0
testtable.each{ 
    //println it[0]----也可以输出指定位置的元素！！
    num = num+1
    println it.id+",year="+it.name
}
//注意要使用${}输出参数的话，必须使用双引号。。。
println "${num}"

println '--------------------------------------'
println "下面显示当前数据库的运行实时状态"
sql.eachRow("show status "){
    //下面在{}里面定义的变量，在外面也找到，也就是作用域是全部的范围！！
    if(it.variable_name=="Uptime")
        uptime = it[1]
    else if (it.variable_name =='Questions')
        questions = it[1]
}
println "数据库运行时间Uptime for Database:${uptime}"
println "数据库查询的条目Number of Queries:${questions}"
println "每分钟的查询条目Queties per Minutes = "+Integer.valueOf(questions)/Integer.valueOf(uptime)

sql.eachRow("show status like 'Com_%'"){
    if(it.variable_name=="Com_insert")
        insertnum = Integer.valueOf(it[1])
    else if (it.variable_name == "Com_select")
        selectnum = Integer.valueOf(it[1])
    else if (it.variable_name == "Com_update")
        updatenum = Integer.valueOf(it[1])
}
println "查询语句有${selectnum},百分比："+100*(selectnum/Integer.valueOf(uptime))+"%"
println "插入语句有${insertnum},百分比："+100*(insertnum/Integer.valueOf(uptime))+"%"
println "更新语句有${updatenum},百分比："+100*(updatenum/Integer.valueOf(uptime))+"%"

println '--------------------------------------'
println '下面将数据库里面的值保存到xml文件'
bldr = new groovy.xml.MarkupBuilder()
bldr.testtable{
    sql.eachRow('select * from testtable'){
        data(id:it.id,name:it.name)
    }
}
println bldr.text()

List

assert [1,3,4] ==(1..4)
//集合是有顺序的！！
assert [1,4] !=[1,4,3]
assert [1,3]+[1] ==[1,1]
//将一个元素添加到已经存在的list中
assert [1,3]<<1 ==[1,1]
//从已有的list中删除元素
assert [1,1]-[1] ==[2,3]*2 ==[1,1,3]
//flatten:扁平的意思
assert [1,[2,3]].flatten() ==[1,3].reverse()==[3,1]
//测试两个集合是否有交叉
assert [1,3].disjoint([4,5,6])
//intersect:得到两个集合中的交集
assert [1,3].intersect([4,1]) ==[3,1]
//对集合进行循环处理
assert [1,3].collect{it+3} ==[4,6]
assert [1,1].unique().size()==3
assert [1,1].count(1) ==2
assert [1,4].min() ==1
assert [1,4].max() ==4
assert [1,4].sum() ==10
assert [4,3].sort() ==[1,4]
//对集合进行循环处理判断，并返回结果
assert [4,3].findAll{it%2==0} ==[4,2]

//对集合的迭代
def expected = [1,'test']
expected.each{test -> println test}


Map：

def map = [a:1,'b':2]
println map    //[a:1,b:2]
println map.a
println map['a']
println map.keySet()  //[a,b]
 
map = [:]
map[1] = 'a';map[2]='b'
map[true] = 'p'
map[false] = 'q'
map[null]='x';map['null'] = 'z'
assert map ==[1:'a',2:'b',(true):'p',(false):'q',(null):'x','null':'z']

//下面的例子很有用，对map进行了很快速的循环输出！！
def sb = new StringBuffer();
[1:'a',3:'c'].each{k,v->sb << "$k:$v,"}

//下面是输出字符串
[1:'a',v-> println "$k:$v,"}

assert sb.toString() =='1:a,2:b,3:c,'

//下面又是一种快速的输出map为字符串形式的方法
map = [1:'a',3:'c']
def string = map.collect{k,v -> "$k:$v"}.join(',')
assert string == '1:a,3:c'  
 
//下面演示一个对city进行分类的例子
assert [
    [name:'C',city:'London'],[name:'S',[name:'M',city:'LA'],[name:'Z',city:'HK'],[name:'A',city:'HK']        
].groupBy{it.city}==[
    London:[ [name:'C',city:'London']],LA:[ [name:'M',city:'LA']],HK:[ [name:'Z',city:'HK'] ]
]

//map中顺序也是有关系的！顺序不对的map也不相等
assert [ [name:1,city:'L'],[name:2,city:'H']] != [ [name:2,city:'H'],[name:1,city:'L']]

闭包的一个例子：

import static java.lang.Math.*

//闭包例子1
piA = { 22/7 }
piB = { 333/106 }
piC = { 355/113 }
piD = { 0.6*(3+sqrt(5))}
piE = { 22/7 +37/47 +888/83}
piF = { sqrt(sqrt(2143/22)) }

//这里就是闭包的实际算法部分。
howCloseToPI = { abs(it.value() - PI) }

algorithms = ['piA':piA,'piB':piB,'piC':piC,'piD':piD,'piE':piE,'piF':piF] 

findBestPI(algorithms)

def findBestPI(map){
    map.entrySet().sort(howCloseToPI).each{
        entry ->//下面调用了闭包的函数
        def diff = howCloseToPI(entry)
        println "Alorithm $entry.key differs by $diff"
    }
}

doubleNum = {num ->num*2}
println doubleNum(3)

//闭包例子2
//下面的方法定义就是使用了闭包。传入了num，closure，其中closure是函数类型。
processThenPrint = {num,closure->
  num = closure(num);println "num is $num"
}
//下面传入了函数名作为第二个参数
processThenPrint(3,doubleNum)
//下面传入第二个参数是匿名函数
processThenPrint(10){it/2}

//闭包例子3
//下面又是一个闭包的例子
def houston(Closure  doit){
   (10..1).each{
       count -> doit(count) 
   }
}

houston{ println it}

//闭包例子4,用于迭代
3.times{println 'Hi'}

[0,2].each{number -> println number}

//注意下面的it！！
[1,5].each{ println it}

def println = {println it}
[4,6].each println

map = ['a':1,'b':2]
map.each{key,value -> map[key]=value*2 }
assert map == ['a':2,'b':4]

//注意下面的each后面是小括号，不是大括号了！
doubler = {key,value -> map[key] = value*2}
map.each(doubler)
assert map == ['a':4,'b':8]

def doubleMethod(entry){
    map[entry.key] = entry.value *2;
}
doubler = this.&doubleMethod
map.each(doubler)
assert map == ['a':8,'b':16]

//下面对集合的一些操作很容易的结合了闭包方法的使用
//查询子元素
assert [1,3].grep{it<3} ==[1,2]
//判断是否有一个满足条件
assert [1,3].any{ it%2==0 }
//判断是否全部满足条件
assert [1,3].every{ it <4}
//将集合中全部元素join
assert (1..9).collect{it}.join() == '123456789'
assert (1..4).collect{it*2}.join() == '2468'

//闭包例子5：新的函数curry！以及演示一个通过闭包将list进行修改的例子！！
def add = {x,y -> x+y}
def mult = {x,y -> x*y}
assert add(1,3) == 4
assert mult(1,3) == 3

def min = {x,y -> [x,y].min()}
def max = {x,y].max()}
def sub = {x,y -> return 'x - y = '+(x-y)}

//注意下面的curry函数，意思是默认的传入参数到原有的函数的第一个位置，并将结果返回为一个新的函数
//例如下面的triple就是得到一个数值的三倍！！
def triple = mult.curry(3);assert triple(2) ==6
def atLeastTen = max.curry(10)
def subTen = sub.curry(10)
assert atLeastTen(5)==10
assert atLeastTen(15) == 15
assert subTen(13) == 'x - y = -3'

//
def pairWise(list,invoke){
    if(list.size()<2) return []
    def next = invoke(list[0],list[1])
    return [next]+pairWise(list[1..-1],invoke)
}

assert pairWise(1..5,add) == [3,7,9]
assert pairWise(1..5,mult) == [2,6,12,20]
assert pairWise(1..5,min) == [1,4]
assert pairWise(1..5,max) == [2,5]

//inject--参数是初始值，然后放在一个闭包里面对list的每个元素进行迭代操作！
assert 'cbaxabc' == ['a','b','c'].inject('x'){
    result,item -> item +result+item
}

对xml的操作

对xml的解析

def CAR_RECORDS = '''
<records>
<car name='HSV Maloo' make='Holden' year='2006'>
<country>Australia</country>
<record type='speed'>Production Pickup Truck with speed of 271kph</record>
</car>
<car name='P50' make='Peel' year='1962'>
<country>Isle of Man</country>
<record type='size'>Smallest Street-Legal Car at 99cm wide and 59 kg in weight</record>
</car>
<car name='Royale' make='Bugatti' year='1931'>
<country>France</country>
<record type='price'>Most Valuable Car at $15 million</record>
</car>
</records>
'''
//解析xml的第一步，进行分析--注意这里的找到的是根节点<records>，所以后面的car。size（）就有值。
def records = new XmlSlurper().parseText(CAR_RECORDS)
//得到节点的数目
assert 3 == records.car.size()
//注意下面的得到car里面的country的条目，而不是直接进行records.country！！
assert 3 == records.car.country.size()
//depthFirst()：计算全部的节点的数目   
assert 10 == records.depthFirst().collect{it}.size()

def firstRecord = records.car[0]
//得到一个节点里面的属性name
assert 'car' == firstRecord.name()
//得到一个节点里面的自定义属性，使用@属性名 
assert 'Holden' == firstRecord.@make.toString()
//text():得到节点里面的文本信息！不是属性。
assert 'Australia' == firstRecord.country.text()

//对节点进行判断，找到make属性含有e的条目数量
assert 2 == records.car.findAll {it.@make.toString().contains('e')}.size()
//使用正则表达式进行节点筛选
assert 2 == records.car.findAll{it.@make=~'.*e.*'}.size()

//找到全部的国家符合正则表达式的record节点的make属性！
assert ['Holden','Peel'] == records.car.findAll{ it.country =~ '.*s.*a.*'}
    .@make.collect{it.toString()}
    
//找到全部的type非空的record节点的type属性！！
assert ['speed','size','price'] == records.depthFirst().grep{it.@type!=''}.'@type'*.toString()

def countryOne = records.car[1].country
//查找父节点的两个方法！parent和使用路径表达式
assert 'Peel' == countryOne.parent().@make.toString()
assert 'Peel' == countryOne.'..'.@make.toString()

//将所有的节点按照指定顺序排序之后，再按顺序输出name属性！注意后面的一个×号!
def names = records.car.list().sort{ it.@year.toInteger()}.'@name'*.toString()
assert ['Royale','P50','HSV Maloo'] == names

myFileDir = "d:"
myFileName = 'mytest.txt'
myFile = new File(myFileDir + myFileName)

printFileLine = { println "File line:"+it}

myFile.eachLine ( printFileLine )

myFile.write('123')
myFile.append('123')

读取属性文件：
Properties properties = new Properties()
properties.load(new FileInputStream("d:conf.properties"))

println properties.getProperty("filename")

正则表达式：

正则表达式：
assert 'Hello World!' =~ /Hello/
assert 'Hello World!' ==~ /Hellob.*/
def p = ~/Hellob.*/
assert p.class.name == 'java.util.regex.Pattern'

//下面的next方法是返回的下一个字符！
assert "1.23".replaceAll(/./){ch-> ch.next()}== "2/34"

assert "1.23".replaceAll(/d/){num -> num.toInteger()+1}=='2.34'

//下面的 == 不可以换行！否则就是语法错误！！为什么？？因为每一行后面默认就是有一个分号的！！
assert "1.23".replaceAll(/d+/){num ->
 num.toInteger()+1} == '2.24'