利用java反射机制实现自动调用类的简单方法

1. 新建testservlet类

package com.yanek.test;

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;

public class testservlet extends httpservlet {

 public void doget(httpservletrequest request, httpservletresponse response)
  throws servletexception, ioexception {
 // 获取类的全路径以及名称
 string classname = request.getparameter("classname");
 // 获取方法名
 string methodname = request.getparameter("method");
 try {
  // 获取class文件
  class<?> t_class = class.forname(classname);
  // 获取该类所需求的方法
  method method = t_class.getdeclaredmethod(methodname,
   httpservletrequest.class, httpservletresponse.class);
  method.invoke(t_class.newinstance(), request, response);// 方法的实现
 } catch (exception e) {
  e.printstacktrace();
 }
 }

 public void dopost(httpservletrequest request, httpservletresponse response)
  throws servletexception, ioexception {
 doget(request, response);
 }

}

2. 建立需要自动调用的类

package com.yanek.test;

import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;

public class test {

 /**
 * @param args
 */
 public static void main(string[] args) {

 system.out.println("hello world !");

 }

 public void test(httpservletrequest request, httpservletresponse response) {
 system.out.println("hello");
 system.out.println(request.getparameter("username"));
 }

}

3. web.xml配置

<?xml version="1.0" encoding="utf-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" xsi:schemalocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
 <servlet>
 <description>test</description>
 <display-name>test</display-name>
 <servlet-name>test</servlet-name>
 <servlet-class>com.yanek.test.testservlet</servlet-class>
 <load-on-startup>1</load-on-startup>
 </servlet>
 <servlet-mapping>
 <servlet-name>test</servlet-name>
 <url-pattern>/test</url-pattern>
 </servlet-mapping>
 <welcome-file-list>
 <welcome-file>index.jsp</welcome-file>
 </welcome-file-list>
 <login-config>
 <auth-method>basic</auth-method>
 </login-config>
</web-app>

4. 启动服务器访问:

http://127.0.0.1:8081/testprj/test?classname=com.yanek.test.test&method=test&username=aspboy

控制台输出:

hello

aspboy

说明: 类com.yanek.test.test类的 方法 public void test(httpservletrequest request, httpservletresponse response) 被执行了.

反射机制是java中的重要功能,在框架设计中大量使用.

测试环境: tomcat6.0

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