通过反射和配置来实现工厂方法，达到解耦和的效果。这也是 spring 的 bean 工厂原理 spring | ApplicationContext 功能详解。
创建一个文件 application.properties
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| UserServiceImpl=com.redisc.UserServiceImpl
|
然后实现
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| interface UserService {
void proc();
}
class UserServiceImpl implements UserService {
@Override
public void proc() {
System.out.println("UserServiceImpl 123");
}
}
class UserServiceFactory {
private static Properties env = new Properties();
static {
InputStream inputStream = Run.class.getResourceAsStream("/application.properties");
try {
env.load(inputStream);
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public static UserService getUserService() throws ClassNotFoundException, IllegalAccessException, InstantiationException {
String userServiceImplPath = env.getProperty("UserServiceImpl");
UserService userService = (UserService) Class.forName(userServiceImplPath).newInstance();
return userService;
}
}
|
UserServiceFactory 通过读取配置的方式，来反射创建实例。
