速度模板循环遍历数组以创建字符串

Question

我正在尝试使用 AWS appsync resolver 中的 velocity templating language 通过遍历字符数组来创建字符串。

给定数组 listOfWords = ["好" "克力"] 我将如何实现 queryString = "+\"好\" +\"克力\""

的字符串输出

到目前为止，我已经完成了这样的事情：

24: #set($listOfWords = ["好" "克力"])
25: #set($queryString = "")
26: #foreach($word in $listOfWords)
27:   #if( $velocityCount == 1 )
28:     #set($queryString = "+\"$word\"")
29:   #else
30:     #set($queryString = $queryString +"+\"$word\"")
31:   #end
32: #end

这个returns错误： Encountered \"$word\" at velocity[line 28, column 37]\nWas expecting one of:\n <RPAREN> ...\n <WHITESPACE> ...\n \"-\" ...\n \"+\" ...\n \"*\" ...\n \"/\" ...\n \"%\" ...\n <LOGICAL_AND> ...\n <LOGICAL_OR> ...\n <LOGICAL_LT> ...\n <LOGICAL_LE> ...\n <LOGICAL_GT> ...\n <LOGICAL_GE> ...\n <LOGICAL_EQUALS> ...\n <LOGICAL_NOT_EQUALS> ...\n

我也试过了

#foreach( $word in $listOfWords )
        #if( $velocityCount == 1 )
            #set($queryString = "+" + "\" + "\"" + $word + "\" + "\"") line 27
        #else
            #set($queryString = $queryString + "+" + "\" + "\"" + $word + "\" + "\"")
        #end
    #end
    )

但似乎导致了词法错误：

"Lexical error, Encountered: \"\\"\" (34), after : \"\\\\\" at *unset*[line 27, column 64]"

Answer 1

无需构建 VTL 变量，您可以直接构建字符串作为输出。有点像 VTL 文档中的这个例子；

<ul>
  #foreach( $product in $allProducts )
    <li>$product</li>
  #end
</ul>

Answer 2

你可以做到：

#set($listOfWords = ["好" "克力"])
#set($q = '"')
#set($queryString = "")
#foreach($word in $listOfWords)
  #if( $velocityCount == 1 )
    #set($queryString = "$q$word$q")
  #else
    #set($queryString = "$queryString+$q$word$q")
  #end
#end

速度模板循环遍历数组以创建字符串

velocity template loop through array to create string

velocity

vtl

aws-appsync