最经典的实例“Hello Servlet”来讲一下Servlet的编译和运行。不同的Web服务器上编译和运行时是不同的，在这里主要是在Tomcat中Servlet的编译和运行的步骤以及注意事项。-The most classic example of " Hello Servlet"　about what the Servlet to compile and run. Different Web servers to compile and run time is different, here is mainly in the Tomcat Servlet compile and run in the steps and precautions.