最近在学密码学，这一个实现playfair加密算法的java类，主要包括构造函数、加密函数和解密函数，还有几个辅助函数，附有测试类，在控制台下运行的。-A recent study of cryptography, which playfair encryption algorithm to achieve a java class, mainly including constructor, encryption and decryption function, a function, and