Nifi Groovy 脚本修改 csv 行给出 MissingMethodException 错误

Question

我正在编写一个 groovy 脚本，它将以下 csv 文件作为输入

Id, Name, Class
1, Kevin,[Eight, Nine]
2, Mark,Four

并按如下方式创建或更改 csv

Id, Name, Class
1, Kevin,Eight
1, Kevin,Nine
2, Mark,Four

基本上，如果列 Class 具有字符串数组，则将其放在多行中以复制所有其他列值。

def flowFile = session.get()
if(!flowFile) return
try {
flowFile = session.write(flowFile, {inputStream, outputStream ->
    outputStream.withWriter("UTF-8"){ w ->
        inputStream.eachLine("UTF-8"){ line ->
            def subString = line.takeBetween('[', ']')
            def splitArray = subString.split(',')
             if(splitArray.length > 1) {
                def lineBefore = line.takeBefore('[');
                def lineAfter = line.takeAfter(']');
                for(int i=0;i<splitArray.length;i++) {
                    w << lineBefore << row.getAt(i) << lineAfter << '\n'
                }
            }else {
                w << line << '\n'
            }
        }
    }
} as StreamCallback)

session.transfer(flowFile, REL_SUCCESS)
}catch(e) {
      log.error('Error capturing nextLink', e)
      session.transfer(flowFile, REL_FAILURE)
}

我收到以下错误：

 Error capturing nextLink: groovy.lang.MissingMethodException: No signature of method: java.lang.String.takeBetween() is applicable for argument types: (String, String) values: [[, ]]

但是 def subString = line.takeBetween("[", "]") 中的 takeBetween 方法在 eclipse

中工作得很好

Answer 1

它在 Eclipse 中运行但不在服务器上运行的事实可能表明服务器上的 groovy 版本早于 3.0（groovy 中引入的 takeBetween 方法3.0).

/**
 * A String variant of the equivalent CharSequence method {@link #takeBetween(CharSequence,CharSequence,CharSequence)}.
 *
 * @param self the original CharSequence
 * @param from beginning of search
 * @param to   end of search
 * @return String that is in between the given two CharSequences and empty if the unavailable inputs are given
 *
 * @since 3.0.0
 */
public static String takeBetween(final String self, final CharSequence from, final CharSequence to) {
    return (String) takeBetween((CharSequence) self, from, to);
}

Answer 2

以下使用 'substring' 方法而不是 'takeBetween' 方法的 groovy 脚本帮助我创建了所需格式的 csv

def flowFile = session.get()
if(!flowFile) return
try {
flowFile = session.write(flowFile, {inputStream, outputStream ->
    outputStream.withWriter("UTF-8"){ w ->
        inputStream.eachLine("UTF-8"){ line ->
         def splitArray = new String[0];
         def subString = "";
         def x = line.indexOf("[")+1;
         def y = line.indexOf("]");
         if(x > 0 && y >0)
         subString = line.substring(x,y);
         if(subString != null && subString.length() >0)
             splitArray = subString.split(',')
             if(splitArray.length > 1) {
                 def lineBefore = line.substring(0,x);
                 def lineAfter = line.substring(y,line.length());
                for(int i=0;i<splitArray.length;i++) {
                    w << lineBefore << splitArray.getAt(i) << lineAfter << '\n'
                }
            }else {
                w << line << '\n'
            }
        }
    }
} as StreamCallback)

session.transfer(flowFile, REL_SUCCESS)
}catch(e) {
      log.error('Error capturing nextLink', e)
      session.transfer(flowFile, REL_FAILURE)
}

Nifi Groovy 脚本修改 csv 行给出 MissingMethodException 错误

Nifi Groovy script to modify csv rows giving MissingMethodException error

csv

groovy

apache-nifi