在 Servlet 上设计简单的 URL Routing - JBTALKS.CC

package com.fyhao.test;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class MainServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String path = request.getPathInfo();
try {
String[] parts = path.split("/");
if(parts.length >= 2) {
try {
Class iClass = Class.forName("com.fyhao.test." + parts[1] + "Service");
Method init;
Constructor con;
Object myClass;
try {
init = iClass.getMethod("init", new Class[] {HttpServlet.class, HttpServletRequest.class, HttpServletResponse.class, String[].class});
con = iClass.getConstructor(new Class[] {});
myClass = con.newInstance(new Object[] {});
init.invoke(myClass, new Object[]{this, request, response, parts});
} catch (NoSuchMethodException ex) {
System.err.println("Please define init method on " + parts[1] + "Service");
return;
} catch (Exception ex) {
System.err.println("init exception");
return;
}
Method m;
if(parts.length >= 3) {
try {
m = iClass.getMethod(parts[2], null);
m.invoke(myClass);
} catch (NoSuchMethodException ex) {
try {
m = iClass.getMethod("main", null);
m.invoke(myClass);
} catch (Exception exc) {
System.err.println("Please define a main service method on " + parts[1] + "Service");
return;
}
} catch (Exception ex) {
System.err.println("service method exception");
return;
}
} else {
try {
m = iClass.getMethod("main", null);
m.invoke(myClass);
} catch (Exception exc) {
System.err.println("Please define a main service method on " + parts[1] + "Service");
return;
}
}
} catch (ClassNotFoundException ex) {
defaultAction(request, response);
}
} else {
defaultAction(request, response);
}
} catch (NullPointerException ex) {
defaultAction(request, response);
return;
}
//serviceclass("Gift", "send");
}
public void defaultAction(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("default action here: " + request.getPathInfo());
}
// leave for reference
public void serviceclass(String c, String service) {
try {
Class iClass = Class.forName("com.fyhao.test." + c + "Service");
Method init = iClass.getMethod("init", null);
Method m = iClass.getMethod(service, null);
Constructor con = iClass.getConstructor(new Class[] {});
Object myClass = con.newInstance(new Object[] {});
m.invoke(myClass);
} catch( Exception ex) {}
}
}

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package com.fyhao.test;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Service {
HttpServlet servlet;
HttpServletRequest request;
HttpServletResponse response;
String[] parts;
public void init(HttpServlet servlet, HttpServletRequest request, HttpServletResponse response, String[] parts) {
this.servlet = servlet;
this.request = request;
this.response = response;
this.parts = parts;
}
}

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package com.fyhao.test;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class GiftService extends Service {
public void main() {
System.out.println("default main methods: ");
}
public void send() {
System.out.println("sending");
}
}

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