如何检查我需要的JFormattedTextField的值？

如何解决如何检查我需要的JFormattedTextField的值？

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<canvas id="canvas" width="1000" height="1000"></canvas>

    

<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/4.0.0/fabric.min.js"></script>
   <script>
  var canvas = new fabric.Canvas('canvas');
  canvas.add(new fabric.Circle({ radius: 30,fill: '#f55',top: 100,left: 100 }));

  canvas.item(0).set({
    borderColor: 'gray',cornerColor: 'black',cornerSize: 12,transparentCorners: true
  });
  canvas.setActiveObject(canvas.item(0));
  canvas.renderAll();

 
function rescale_canvas_if_needed(){
    var optimal_dimensions = [400,400];
    var scaleFactorX=window.innerWidth/optimal_dimensions[0];
    var scaleFactorY=window.innerHeight/optimal_dimensions[1];
    if(scaleFactorX <  scaleFactorY && scaleFactorX < 1) {
        canvas.setWidth(optimal_dimensions[0] *scaleFactorX);
        canvas.setHeight(optimal_dimensions[1] *scaleFactorX);
        canvas.setZoom(scaleFactorX);
    } else if(scaleFactorX >  scaleFactorY && scaleFactorY < 1){
        canvas.setWidth(optimal_dimensions[0] *scaleFactorY);
        canvas.setHeight(optimal_dimensions[1] *scaleFactorY);
        canvas.setZoom(scaleFactorY);
    }else {
        canvas.setWidth(optimal_dimensions[0] );
        canvas.setHeight(optimal_dimensions[1] );
        canvas.setZoom(1);
    }

    canvas.calcOffset();
    canvas.renderAll();
}

 
function handle_resize(){
    $(".canvas-container").hide();
    rescale_canvas_if_needed();
    $(".canvas-container").show();               
     
}
var resizeId = null;
$(function() {
    $(window).resize(function() {
        if(resizeId != null)
        clearTimeout(resizeId);
        resizeId = setTimeout(handle_resize,500);
     });
    console.log( "ready!" );
    /* auto size it right away... */
    resizeId = setTimeout(handle_resize,500);
});
    </script>

使用此代码，我从用户那里得到一个电话号码。例如“（[phone]”。

如果用户什么都不写，我得到一个像这样的字符串“（0）--”。如何检查它是否为空。用户是否写下了所有数字。

解决方法

String text = formattedTextField.getText().toString();
Boolean flag1 = Character.isDigit(text.charAt(2));

if(flag1){
   System.out.println("NUMBER");
}else{
   System.out.println("NOT NUMBER");
}

我可以检查这段代码。