iText PDF表单：如何更改字段的工具提示？

我正在使用烘焙到ColdFusion中的iText库重命名PDF表单字段。我可以很容易地重命名字段名，但是当您将鼠标悬停在与字段新名称不匹配的字段上时，生成的PDF将显示工具提示

我做了一些研究，看起来工具提示存储在字段字典的/TU键中，可以使用setUserName方法进行设置。但是，当我检查代码中的各种对象时，我看不到任何方法可以访问特定PDF字段的方法

如何使用iText库设置此/TU键

以下是我目前的代码：

 function renameFields( pathToFile ) {

    // initialize the PDF file we will be working on
    local.pdfService = new pdf();
    local.pdfService.setSource( arguments.pathToFile );
    local.pdfFile = local.pdfService.read();

    // initialize the iText library objects
    local.pdfReader = createObject("java", "com.lowagie.text.pdf.PdfReader").init( toBinary( local.pdfFile ) );
    local.outputStream = createObject("java", "java.io.ByteArrayOutputStream").init();
    local.pdfStamper = createObject("java", "com.lowagie.text.pdf.PdfStamper").init( local.pdfReader, local.outputStream);

    // get an instance of the acro fields object
    local.acroFields = local.pdfStamper.getAcroFields();

    // Get All of the Fields of the PDF
    local.allFields = local.acroFields.getFields();

    // convert the collection of fields into an array for easy iteration
    local.fieldArray = listToArray( structKeyList( local.acroFields.getFields() ) );

    // loop through all fields and rename them
    for ( var a=1; a < arrayLen( local.fieldArray ); a++ ) {

         // do the actual renaming
         local.acroFields.renameField( local.fieldArray[a], "field_#a#" );

         // update the field tooltip ???

    }

    // finish up and return the pdf file object
    local.pdfStamper.setFormFlattening( false );
    local.pdfStamper.close();
    local.pdfReader.close();
    local.myPdf = local.outputStream.toByteArray();

    return local.myPdf;

}

CFML解决方案更新7/31/2018

注意：在此解决方案中，我首先更改工具提示，然后重命名字段

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我不知道ColdFusion语法，但解决方案应该如下所示：

// loop through all fields and rename them
for ( var a=1; a < arrayLen( local.fieldArray ); a++ ) {

     // do the actual renaming
     local.acroFields.renameField( local.fieldArray[a], "field_#a#" );

     // update the field tooltip (if you already renamed it might have to use the new name)
     Item field = local.acroFields.getFieldItem(local.fieldArray[a]);
     field.getValue(0).put(PdfName.TU, new PdfString("SomeNewTooltip"));
}

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你是救命恩人！为了使用CFML，我不得不稍微调整一下您的解决方案，但最终它让我找到了正确的答案。关于工作代码，请参见我的原始问题。非常感谢你！

// loop through all fields and rename them
for ( var a=1; a < arrayLen( local.fieldArray ); a++ ) {

     // do the actual renaming
     local.acroFields.renameField( local.fieldArray[a], "field_#a#" );

     // update the field tooltip (if you already renamed it might have to use the new name)
     Item field = local.acroFields.getFieldItem(local.fieldArray[a]);
     field.getValue(0).put(PdfName.TU, new PdfString("SomeNewTooltip"));
}