import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.List;

//普通dao接口
interface SearchDao{
    List<Object>  selectList(String msg);
}
//对应mybatis中的SqlSession
interface SqlSession{
    
    Object  selectOne(String statement);
}
//对应mybatis中的DefaultSqlSession
class DefaultSqlSession implements SqlSession{

    public Object selectOne(String statement) {
        System.out.println(statement);
        return null;
    }    
}
/*
 * 代理对象创建工厂
 */
class MapperProxyFactory{
    Class<?>  targetInterface;
    
    public MapperProxyFactory(Class<?> targetInterface ) {
        this.targetInterface = targetInterface;
    }
    
    Object newInstance(MapperProxyHandler mapperProxyHandler) {
        return  Proxy.newProxyInstance(targetInterface.getClassLoader(), new Class[] {targetInterface},mapperProxyHandler); 
    }
}

/*
 * 代理对象处理器对应mybatis中的MapperProxy,处理业务的
 */
class MapperProxyHandler implements InvocationHandler{

    private SqlSession sqlSession;
    private Class<?>  targetInterface;
    
    public MapperProxyHandler(SqlSession sqlSession, Class<?> targetInterface) {
        super();
        this.sqlSession = sqlSession;
        this.targetInterface = targetInterface;
    }

    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        String statement=targetInterface.getName()+"."+method.getName();
        sqlSession.selectOne(statement);
        return null;
    }
}

public class MapperProxyTest {
    public static void main(String[] args) {        
        SqlSession sqlSession=new DefaultSqlSession();
        MapperProxyHandler proxyHandler=new MapperProxyHandler(sqlSession,SearchDao.class);
    
        MapperProxyFactory factory= new MapperProxyFactory(SearchDao.class);        
        SearchDao dao=(SearchDao) factory.newInstance(proxyHandler);    
        System.out.println("代理对象: "+dao.getClass().getName());
        dao.selectList("test");
    }
}