Groovy文字StringBuilder/StringBuffer

Question

Groovy支持用于创建StringBuilder/StringBuffer的文字语法,而不是通常的

def sb = new StringBuilder()

但是,我似乎无法记住(或在Google上找到)正确的语法.

Answer 1

要在一个步骤中获得StringBuffer,您可以使用

def sb = 'Hello'<<''

甚至:

def sb = ''<<'' //4 single quotes, not double quotes

对于最初空的.

我认为(但我可能错了)使用StringBuffer而不是StringBuilder的原因是为了保持与Java 1.4的兼容性.

Answer 2

创建StringBuilder

text = 'Hello '

追加

text <<= 'World!'

这可能会有所帮助.

Answer 3

我刚刚在Groovy中使用了StringBuilder/StringBuffer.

以下是一些例子:

// << operator example
def year = StringBuilder.newInstance()
year << 2
year << "0"
year << '1' << 4
assert year.toString() == "2014"

// You can use with operator
def month = StringBuilder.newInstance()
month.with {
    append "0"
    append '5'
}
assert month.toString() == "05"

// or just append String like in Java or you can leave parenthesis
def day = StringBuilder.newInstance()
day.append "1"
day.append('1')
assert day.toString() == '11'

// It's nice to know, that we can use StringBuilder directly in GString
def date = "$year-${month}-$day"
assert date == "2014-05-11"

注意: 仅在一个线程使用时使用StringBuilder.StringBuilder提供与StringBuffer兼容的API.StringBuffer是同步的,StringBuilder不是.请查看此链接以获取更多信息.