Servlet里doGet过多的判断method语句,会让代码略显冗余,此时可以用一个BaseServlet类反射调用Servlet里的方法,从而可以省略去Servlet里doGet和doPost语句;
代码实现如下:
import java.io.IOException;
import java.lang.reflect.Method;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//编写BaseServlet继承HttpServlet
//重写其doGet和doPost方法
public class BaseServlet extends HttpServlet {
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//获取请求参数中的method
String method = req.getParameter("method");
if(method!=null){
try {
//通过反射调用对应的方法
//通过“this”获取class对象
Class clazz = this.getClass();
//通过class对象和方法名获取方法对象
Method m = clazz.getMethod(method, HttpServletRequest.class,HttpServletResponse.class);
//通过反射机制调用方法
m.invoke(this, req,resp);
} catch (Exception e) {
e.printStackTrace();
}
}
}
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
}
注意:
1.那么Servlet继承Baseservlet类即可:如
public class UserServlet extends BaseServlet{
…
}
2.继承Baseservlet的Servlet里的doGet和doPost注释掉或者删除即可。