计算器原码（Java开发环境，最简单易懂的代码）-Calculator of the original code (Java development environment, the most straightforward code)

Java计算器，这是一个简单的计算器，用java代码实现。用面板，按钮简单组件组成。(Java calculator, this is a simple calculator, implemented in Java code. With the panel, the button is made up of the simple components.)