HttpServlet
HttpServlet
1)是一个Servlet，继承自GenericServlet。针对于HTTP协议所制定
2）在service()方法中直接把ServletRequest和ServletResponse转为HttpServletRequest和HttpServletResponse，并调用了重载的service(HttpServletRequest,HttpServletResponse)
3)在service(HttpServletRequest,HttpServletResponse)获取了请求方式：request.getMethod().根据请求方式创建了doXxx()方法（xxx为具体的请求方式，比如doGet，doPost）
4）实际开发中，直接继承HttpServlet，并根据请求方式复写doXxx()方法
5）优点：直接有针对性的覆盖doXxx()方法
public class MyHttpServlet extends GenericServlet{
@Override
public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
HttpServletRequest request;
HttpServletResponse response;
try {
request = (HttpServletRequest) servletRequest;
response = (HttpServletResponse) servletResponse;
}catch (ClassCastException e){
throw new ServletException("non-HTTP request or response");
}
service(request,response);
}
public void service(HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse){
String method = httpServletRequest.getMethod();
if ("GET".equalsIgnoreCase(method)){
doGet(httpServletRequest,httpServletResponse);
}else if ("POST".equalsIgnoreCase(method)){
doPost(httpServletRequest,httpServletResponse);
}
}
public void doGet(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) {
}
public void doPost(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) {
}
}