设计如下图的图形用户界面并实现其相应功能（请给出代码）。在下图中，从JComboBox中选择的运算，可对在第一个文本框的第一个数和在第二个文本框中第二个数进行加、减、乘和除，结果在最后一个文本框中显示。请给出程序的代码并把程序运行的结果截图。-Design as shown in the graphical user interface and implement their respective functions (Please give the code). In the figure below, selected　the JComboBox in operation, may number in the first box of the first text in the second text box and the second number addition, subtraction, multiplication and division, resulting in a final text display box. Please give the code of the program and the results of running shots.