Mule 4中如何正确转义反斜杠(\)？

我写了一个用于替换特殊字符的DataWeave函数，其他特殊字符的转义都正常，但反斜杠()始终无法被正确转义。尝试在searchReplace数组中添加{ searchValue: "\", replaceValue: "\\" }完全没用，原函数代码如下：

%dw 2.0
output application/java

var searchReplace = [
        {
            searchValue: "?",
            replaceValue: "\?"
        },
        {
            searchValue: "&",
            replaceValue: "\&"
        },
        {
            searchValue: "|",
            replaceValue: "\|"
        },
        {
            searchValue: "!",
            replaceValue: "\!"
        },
        {
            searchValue: "^",
            replaceValue: "\^"
        },
        {
            searchValue: "~",
            replaceValue: "\~"
        },
        {
            searchValue: "*",
            replaceValue: "\*"
        },
        {
            searchValue: ":",
            replaceValue: "\:"
        },
        {
            searchValue: "+",
            replaceValue: "\+"
        },
        {
            searchValue: "'",
            replaceValue: "\'"
        },
        {
            searchValue: "-",
            replaceValue: "\-"
        },
        {
            searchValue: "{",
            replaceValue: "\{"
        },
        {
            searchValue: "}",
            replaceValue: "\}"
        },
        {
            searchValue: "[",
            replaceValue: "\["
        },
        {
            searchValue: "]",
            replaceValue: "\]"
        },
        {
            searchValue: "(",
            replaceValue: "\("
        },
        {
            searchValue: ")",
            replaceValue: "\)"
        }
]
fun replaceValuesArray(n,text,values) =
if (n == 0) text replace values[n].searchValue with(values[n].replaceValue) else replaceValuesArray(n - 1, text replace values[n].searchValue with(values[n].replaceValue), values)
var searchTerm = replaceValuesArray(sizeOf(searchReplace) - 1,payload.search, searchReplace)
---
if ((searchTerm == "") or (searchTerm == null)) "" else (searchTerm ++ "*")

问题原因 #

DataWeave中，单个反斜杠\是转义字符，用来表示特殊字符（比如换行、引号等）。如果要表示一个实际的反斜杠字符，必须用双反斜杠\\来转义。之前添加的条目里，searchValue: "\"会被DataWeave解析为不完整的转义序列，根本无法正确匹配输入中的反斜杠。

解决方法 #

在searchReplace数组中添加正确的反斜杠替换条目：

{
    searchValue: "\\",
    replaceValue: "\\\\"
}

• searchValue: "\\"：DataWeave会将其解析为单个反斜杠字符，用来匹配输入中的\
• replaceValue: "\\\\"：DataWeave会将其解析为两个反斜杠字符，也就是转义后的目标结果\\

修改后的完整代码 #

%dw 2.0
output application/java

var searchReplace = [
        {
            searchValue: "?",
            replaceValue: "\?"
        },
        {
            searchValue: "&",
            replaceValue: "\&"
        },
        {
            searchValue: "|",
            replaceValue: "\|"
        },
        {
            searchValue: "!",
            replaceValue: "\!"
        },
        {
            searchValue: "^",
            replaceValue: "\^"
        },
        {
            searchValue: "~",
            replaceValue: "\~"
        },
        {
            searchValue: "*",
            replaceValue: "\*"
        },
        {
            searchValue: ":",
            replaceValue: "\:"
        },
        {
            searchValue: "+",
            replaceValue: "\+"
        },
        {
            searchValue: "'",
            replaceValue: "\'"
        },
        {
            searchValue: "-",
            replaceValue: "\-"
        },
        {
            searchValue: "{",
            replaceValue: "\{"
        },
        {
            searchValue: "}",
            replaceValue: "\}"
        },
        {
            searchValue: "[",
            replaceValue: "\["
        },
        {
            searchValue: "]",
            replaceValue: "\]"
        },
        {
            searchValue: "(",
            replaceValue: "\("
        },
        {
            searchValue: ")",
            replaceValue: "\)"
        },
        // 新增的反斜杠替换条目
        {
            searchValue: "\\",
            replaceValue: "\\\\"
        }
]
fun replaceValuesArray(n,text,values) =
if (n == 0) text replace values[n].searchValue with(values[n].replaceValue) else replaceValuesArray(n - 1, text replace values[n].searchValue with(values[n].replaceValue), values)
var searchTerm = replaceValuesArray(sizeOf(searchReplace) - 1,payload.search, searchReplace)
---
if ((searchTerm == "") or (searchTerm == null)) "" else (searchTerm ++ "*")

内容的提问来源于stack exchange，提问作者SH4444KO