一个servlet响应多个请求实现方式--反射

只需写一个servlet，作为一个中转站。

根据传来的参数className反射获取对应的类字节码，methodName反射获取对应的方法。然后调用。

@WebServlet("/CenterServlet")
public class CenterServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String className = request.getParameter("className");
className = "com.wu.action."+className;
String methodName = request.getParameter("methodName");
Class clazz = null;
Method method = null;
//className=com.wu.action.LoginAction 这里的className要完整
clazz = Class.forName(className);//
method = clazz.getDeclaredMethod(methodName,HttpServletRequest.class,HttpServletResponse.class);
method.invoke(clazz,request, response);
//object is not an instance of declaring class说明未实例化，我们可以让反射的方法称为静态，就不要实例化了。
//method.invoke(request, response);wrong number of arguments
//对于静态的，只需传入clazz。method.invoke(clazz,request, response);
//或者也可以method.invoke(_class.newInstance(), args);
}
}
创建其他普通的java类
public class LoginAction {
public static void login(HttpServletRequest request, HttpServletResponse response){
PrintWriter out = response.getWriter();
out.write("LoginAction login");
System.out.println("LoginAction login");
}
public static void login1(HttpServletRequest request, HttpServletResponse response){
PrintWriter out = response.getWriter();
out.write("LoginAction login1");
System.out.println("LoginAction login1");
}
}

需要调用的时候：用参数指定类名 方法名

http://localhost:8080/OnlineOrder/CenterServlet?className=LoginAction&methodName=login1

为了写成实现以下这种url：用路径信息指定类名 方法名

http://localhost:8080/OnlineOrder/CenterServlet/

className /methodName?userName=wuyiming&password=123456

首先：

@WebServlet(“/CenterServlet”)

改成：@WebServlet(“/CenterServlet/*”)

这样就能匹配/CenterServlet/*的各种url。

调用request.getPathInfo()能获取 / className / methodName

通过截取pathInfo.substring(1,pathInfo.length()).split(“/”);

就可以获得className或methodName

String pathInfo = request.getPathInfo();

String[] classAndMethodName = pathInfo.substring(1,pathInfo.length()).split(“/”);

String className = “com.wu.action.”+classAndMethodName[0];

String methodName = classAndMethodName[1];