在Java/groovy中将Array转换为字符串

Question

我有一个这样的列表:

List tripIds    = new ArrayList()
def sql = Sql.newInstance("jdbc:mysql://localhost:3306/steer", "root",
            "", "com.mysql.jdbc.Driver")
        sql.eachRow("SELECT trip.id from trip JOIN department WHERE organization_id = trip.client_id AND  department.id =1") {
            println "Gromit likes ${it.id}"
            tripIds << it.id
        } 

现在印刷三脚架给我的价值

  [1,2,3,4,5,6,]

现在我想将此列表转换为简单的字符串

 1,2,3,4,5,6

我该怎么做

Answer 1

使用join,例如,

tripIds.join(", ")

不相关,但是如果你只想创建一个来自另一个列表的东西的列表,你最好做一些像map或者collect手动创建一个列表并附加到它的东西,这不是惯用的,例如(未经测试),

def sql = Sql.newInstance("jdbc:mysql://localhost:3306/steer", "root", "", "com.mysql.jdbc.Driver")
def tripIds = sql.map { it.id }

或者,如果您只关心生成的字符串,

def tripIds = sql.map { it.id }.join(", ")

Answer 2

在groovy:

def myList = [1,2,3,4,5]
def asString = myList.join(", ")

Answer 3

使用Groovy添加到Collection 的join方法

List l = [1,2,3,4,5,6]
assert l.join(',') == "1,2,3,4,5,6"