利用java反射创建通用Servlet

动态调用Servlet方法

最新推荐文章于 2020-11-30 20:09:31 发布

原创最新推荐文章于 2020-11-30 20:09:31 发布 · 507 阅读

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本文介绍了一种在Servlet中通过反射动态调用方法的实现方式，根据请求参数选择执行不同的业务逻辑，如添加和删除操作，并实现了页面转发。

package web;

import java.io.IOException;
import java.lang.reflect.Method;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class TestServlet
 */
@WebServlet("/TestServlet")
public class TestServlet extends HttpServlet {

	protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		
		try {
			String action = request.getParameter("action");
			
			//将本类转为字节码
			Class clazz = this.getClass();
			
			//在本类中查找是否有对应方法  
            //public * action（HttpServletRequest ， HttpServletResponse）
			Method method = clazz.getMethod(action, HttpServletRequest.class , HttpServletResponse.class);
			
			//如果有
			if(method != null) {
				
				//调用该方法
				String desPath = (String)method.invoke(this, request , response);
				
				if(desPath != null) 
					//转发
					request.getRequestDispatcher(desPath).forward(request, response);
			}
			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
	public String add(HttpServletRequest request, HttpServletResponse response) {
		
		//有关添加的Servlet操作
		
		System.out.println("添加");
		//返回字符串用于service方法转发页面
		return "add.jsp";
		
	}
	
	public String del(HttpServletRequest request, HttpServletResponse response) {
		
		//有关删除的Servlet操作
		
		System.out.println("删除");
		//返回字符串用于service方法转发页面
		return "del.jsp";
		
	}

}

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
    <!-- action带参数，在Testservlet页面使用request获取-->
	<a href = "${pageContext.request.contextPath}/TestServlet?action=add">添加</a>
	<a href = "${pageContext.request.contextPath}/TestServlet?action=del">删除</a>
		
</body>
</html>