Apache POI XSSF从RGB设置fillForegroundColor

Question

I'm trying to set custom fill colors in an XSSF spreadsheet, but so far have only been able to add colors based on the default colors available in either java.awt.Color or org.apache.poi.ss.usermodel.IndexedColors. Here's what I have that works:

// setup
var workbook= CreateObject( 
    "java",
    "org.apache.poi.xssf.usermodel.XSSFWorkbook"
).Init();

var sheet = workbook.CreateSheet('test');
var row = sheet.CreateRow( 0 );

// first cell, using IndexedColors
var cell = row.createCell( 0 );
cell.setCellValue('test');

var IC = CreateObject( 
    "java",
    "org.apache.poi.ss.usermodel.IndexedColors"
);
var style = workbook.createCellStyle();
style.setFillPattern(style.SOLID_FOREGROUND);
style.setFillForegroundColor(IC.SKY_BLUE.getIndex());
cell.setCellStyle(style);

// second cell, using java.awt.Color
var cell2 = row.createCell( 1 );
cell2.setCellValue('test two');

var C = CreateObject( 
    "java",
    "java.awt.Color"
);
var XSSFColor = createObject("java", "org.apache.poi.xssf.usermodel.XSSFColor");
var myColor = XSSFColor.init(C.BLUE);   
var style2 = workbook.createCellStyle();
style2.setFillPattern(style2.SOLID_FOREGROUND);
style2.setFillForegroundColor(myColor);
cell2.setCellStyle(style2);

var FileOutputStream = CreateObject(
    "java",
    "java.io.FileOutputStream"
).Init( myFileName );

// Write the workout data to the file stream.
workbook.Write( 
    FileOutputStream 
);

// Close the file output stream. 
FileOutputStream.Close();

So that all works; however, I'm still no closer to getting colors using RGB values. Assuming that I want to create an XSSFColor using a java.awt.Color, I should be able to create a Color object using any number of constructors. From https://docs.oracle.com/javase/7/docs/api/java/awt/Color.html , here's what I've tried; all of these throw "the init method was not found":

var C = CreateObject( 
    "java",
    "java.awt.Color"
);
// constructor Color(int r, int g, int b)
// var c1 = C.init(197,217,241); 
// constructor Color(int r, int g, int b, int a)
// var c1 = C.init(197,217,241,255);
// constructor Color (float r, float g, float b);
// var c1 = C.init(0.0, 0.5, 1.0);

Now, XSSFColor has a constructor that allow you to pass a byte array; that brings me to my next problem. Putting aside for the moment the fact that Java bytes are signed, if I try to create a byte array and pass that to the constructor like so, an exception is thrown:

var bytes = javaCast(
    "byte[]",
    [
        javaCast("byte", 50), 
        javaCast("byte", 50), 
        javaCast("byte", 50)
    ]
);
var XSSFColor = createObject("java", "org.apache.poi.xssf.usermodel.XSSFColor");
var c1 = XSSFColor.init(bytes); // throws "Unable to find a constructor for class org.apache.poi.xssf.usermodel.XSSFColor that accepts parameters of type ( [B )."

Finally, java.awt.Color has a Constructor defined as

Color(int rgb) Creates an opaque sRGB color with the specified combined RGB value consisting of the red component in bits 16-23, the green component in bits 8-15, and the blue component in bits 0-7.

I'm afraid I have no idea how to create the combined RGB value so am not able to try :-(

Answer 1

"the init method was not found"

Actually the full error message says (emphasis mine):

Either there are no methods with the specified method name and argument types or the init method is overloaded with argument types that ColdFusion cannot decipher reliably . ColdFusion found 2 methods that match the provided arguments. If this is a Java object and you verified that the method exists, use the javacast function to reduce ambiguity.

Unlike CF, java is strongly typed. So classes like java.awt.Color can contain multiple constructors with the same number of parameters, but different data types. For example:

• Color(float r, float g, float b)
• Color(int r, int g, int b)

Since CF is weakly typed, it is not sure which of those constructors you want to invoke. To resolve the ambiguity, you need to use javacast() on the parameters, ie:

var color = CreateObject( "java","java.awt.Color").init(
         javacast("int", redValue)
        , javacast("int", greenValue)
        , javacast("int", blueValue)
   );

Side note, you can also create java.awt.Color objects from a hexadecimal string using the static Color.decode() method:

 var color = CreateObject( "java","java.awt.Color").decode("##323232");