1\annotation 写法

package com.gyarmy.testannotation;



import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;





@Retention(RetentionPolicy.RUNTIME)

public @interface DbInfo {



	String driverClass();



	String username();



	String password();



	String url();



}

2\ 使用annotation 

package com.gyarmy.testannotation;



import java.lang.reflect.Method;

import java.sql.Connection;

import java.sql.DriverManager;



import org.junit.Test;







public class JdbcUtils {

	

	@Test

	public void test1() throws Exception

	{

		Connection c1 = getConnection();

		System.out.println(c1);

	}

	

	@DbInfo(driverClass="com.mysql.jdbc.Driver",username="root",password="luobo360",url="jdbc:mysql://localhost/test002")

	public Connection getConnection() throws Exception{

		Class clazz = Class.forName("com.gyarmy.testannotation.JdbcUtils");

		Method method = clazz.getMethod("getConnection", null);

		

		boolean isPresent = method.isAnnotationPresent(DbInfo.class);

		System.out.println(isPresent);

		

		if(isPresent){

			DbInfo annotation = method.getAnnotation(DbInfo.class);

			String driverClass = annotation.driverClass();

			String username = annotation.username();

			String password = annotation.password();

			String url = annotation.url();

			

			//注册驱动

			Class.forName(driverClass);

			

			//获得连接

			Connection connection = DriverManager.getConnection(url, username, password);

			return connection;

			

		}

		

		

	

		return null;

	}

	

	

}