靜態代理 ``` 程序運行前已經存在代理類的字節碼文件，代理類和委托類的關系在運行前就確定了 ``` 示例: IUserDao ~~~ public interface IUserDao { void save(); } ~~~ IUserDaoImpl ~~~ public class IUserDaoImpl implements IUserDao { @Override public void save() { System.out.println("保存數據"); } } ~~~ UserDaoProxy ~~~ public class UserDaoProxy implements IUserDao { private IUserDao target; public UserDaoProxy(IUserDao target) { this.target = target; } @Override public void save() { System.out.println("保存前....."); target.save(); System.out.println("保存后....."); } } ~~~ 測試 ~~~ IUserDao iUserDao = new IUserDaoImpl(); UserDaoProxy proxy = new UserDaoProxy(iUserDao); proxy.save(); ~~~ 保存前..... 保存數據 保存后.....