google juice入门

• juice是google的一个轻量级的DI框架，下面上代码。
• 首先是几个接口

public interface UserService {
     void process();
}

public interface LogService {

    void log(String msg);
}

public interface Application {

    void work();
}

• 对应的实现类

public class UserServiceImpl implements UserService{

    public void process() {

        System.out.println("do some service...");
    }
}

public class LogServiceImpl implements LogService{

    public void log(String msg) {

        System.out.println("log----" + msg);

    }

}

public class MyApp implements Application {
    //@Inject标识需要被注入的对象
    @Inject
    private UserService userService;
    @Inject
    private LogService logService;
    public void work() {
        userService.process();
        logService.log("server is running...");
    }
}

• 接口和实现类的绑定

public class MyAppModule extends AbstractModule {
    /**
     * 配置接口和实现类之间的依赖关系
     */
    @Override
    protected void configure() {
        bind(LogService.class).to(LogServiceImpl.class);
        bind(UserService.class).to(UserServiceImpl.class);
        bind(Application.class).to(MyApp.class);
    }
}

• 测试

public class MyAppTest extends TestCase {
    private static Injector injector;
    @BeforeClass
    protected void setUp() {
        injector = Guice.createInjector(new MyAppModule());
    }
    @Test
    public void testMyApp() {
        MyApp app = injector.getInstance(MyApp.class);
        app.work();
    }
}

• 结果

do some service...
log----server is running...