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技術社區[雲棲]
利用java反射機製實現自動調用類的方法
1. 新建TestServlet類
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 {
// 獲取類的全路徑以及名稱
String className = request.getParameter("className");
// 獲取方法名
String methodName = request.getParameter("method");
try {
// 獲取class文件
Class<?> t_class = Class.forName(className);
// 獲取該類所需求的方法
Method method = t_class.getDeclaredMethod(methodName,
HttpServletRequest.class, HttpServletResponse.class);
method.invoke(t_class.newInstance(), request, response);// 方法的實現
} catch (Exception e) {
e.printStackTrace();
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
2. 建立需要自動調用的類
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="https://java.sun.com/xml/ns/javaee"
xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="https://java.sun.com/xml/ns/javaee https://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. 啟動服務器訪問:
https://127.0.0.1:8081/TestPrj/Test?className=com.yanek.test.Test&method=test&username=aspboy
控製台輸出:
hello
aspboy
說明: 類com.yanek.test.Test類的 方法 public void test(HttpServletRequest request, HttpServletResponse response) 被執行了.
反射機製是java中的重要功能,在框架設計中大量使用.
測試環境: tomcat6.0
最後更新：2017-04-02 22:16:31