Groovy GString的问题

问题描述

我想在groovy GString中使用$宏。当我写这段代码的时候


['cdata'，'tdata']。each {
def sql =select * from $ it_1
}


我得到错误未知属性$ it _

好吧，我正在重写它$ / $>


['cdata'， 'tdata']。每个{
def sql =select * from $ {it} _1
}


然后我在结果字符串中获取不需要的引号 - select * from'cdata'_1

问题是我如何使用$ - 宏在GString到达select * from cdata_1结果字符串？

解决方案

您可以使用Groovy的Sql扩展功能来帮助这里。下面的代码可以做到这一点：

  ['cdata'，'tdata']。each {table  - > def sql =select * from $ {Sql.expand table} _1} 
  

如果你在GString中有其他参数，这一点尤其重要：

  def name ='Charlie Sheen'
 def tables = [ 'normalPeople'，'crazyPeople'] 
 tables.each {table  - > 
 def sqlString =select * from $ {Sql.expand table} where name = $ {name}
 / *在这里执行SQL * / 
} 
  
 
 $ b在上面的例子中，准备好的语句仍然会被使用，'name'变量的内容仍然会作为参数处理从而有助于保护您免受SQL注入攻击），但table variable参数将正确扩展。
 
I'm want use $ macro in groovy GString. When i'm wrote this code


['cdata','tdata'].each {
   def sql = "select * from $it_1"
}


i'm get error unknown property $it_

ok, i'm rewrite it


['cdata','tdata'].each {
   def sql = "select * from ${it}_1"
}


then i'm get unwanted quotes in result string - "select * from 'cdata'_1"

Question is how i'm can use $-macro in GString to achive "select * from cdata_1" result string?
 解决方案 
You can use Groovy's Sql expand feature to help here. The following code will do the trick:
['cdata','tdata'].each {table -> def sql = "select * from ${Sql.expand table}_1" }
Using this method is particularly important if you have other parameters in your GString:
def name = 'Charlie Sheen'
def tables = ['normalPeople','crazyPeople']
tables.each { table -> 
    def sqlString = "select * from ${Sql.expand table} where name = ${name}"
    /* Execute SQL here */
}
In the example above a prepared statement will still be used, and the contents of the 'name' variable will still be handled as a parameter (thus helping to protect you against SQL injection attacks) but the table variable parameter will be expanded correctly.
                        
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