使用注释配置的Spring控制台应用程序

Question

我想创建spring控制台应用程序(从命令行运行maven,例如:mvn exec:java -Dexec.mainClass ="package.MainClass").

这个应用程序我想要一些服务和dao层.我知道如何为Web应用程序执行此操作,但我还没有找到有关如何在控制台应用程序中执行操作的任何信息(可能使用Swing).

我正在尝试创建类似的东西:

public interface SampleService {
 public String getHelloWorld();
}


@Service
public class SampleServiceImpl implements SampleService {
 public String getHelloWorld() {
  return "HelloWorld from Service!";
 }
}

public class Main {
 @Autowired
 SampleService sampleService;
 public static void main(String [] args) {
  Main main = new Main();
  main.sampleService.getHelloWorld();
 }
}

可能吗？我能找到一个如何做的例子吗？

Answer 1

看看Spring Reference,3.2.2实例化容器.

为了在控制台应用程序中使用Spring,您需要创建一个实例ApplicationContext并从中获取Spring管理的bean.

参考中描述了使用XML配置创建上下文.对于完全基于注释的方法,您可以这样做:

@Component // Main is a Spring-managed bean too, since it have @Autowired property
public class Main {
    @Autowired SampleService sampleService;
    public static void main(String [] args) {
        ApplicationContext ctx = 
            new AnnotationConfigApplicationContext("package"); // Use annotated beans from the specified package

        Main main = ctx.getBean(Main.class);
        main.sampleService.getHelloWorld();
    }
}

Answer 2

Spring Reference建议在方法中使用ClassPathXmlApplicationContextmain来创建应用程序上下文,然后调用该getBean方法从应用程序上下文获取对bean的初始引用.在编写了相同的代码几次之后,您最终会将样板重构为此实用程序类:

/**
 * Bootstraps Spring-managed beans into an application. How to use:
 * <ul>
 * <li>Create application context XML configuration files and put them where
 * they can be loaded as class path resources. The configuration must include
 * the {@code <context:annotation-config/>} element to enable annotation-based
 * configuration, or the {@code <context:component-scan base-package="..."/>}
 * element to also detect bean definitions from annotated classes.
 * <li>Create a "main" class that will receive references to Spring-managed
 * beans. Add the {@code @Autowired} annotation to any properties you want to be
 * injected with beans from the application context.
 * <li>In your application {@code main} method, create an
 * {@link ApplicationContextLoader} instance, and call the {@link #load} method
 * with the "main" object and the configuration file locations as parameters.
 * </ul>
 */
public class ApplicationContextLoader {

    protected ConfigurableApplicationContext applicationContext;

    public ConfigurableApplicationContext getApplicationContext() {
        return applicationContext;
    }

    /**
     * Loads application context. Override this method to change how the
     * application context is loaded.
     * 
     * @param configLocations
     *            configuration file locations
     */
    protected void loadApplicationContext(String... configLocations) {
        applicationContext = new ClassPathXmlApplicationContext(
                configLocations);
        applicationContext.registerShutdownHook();
    }

    /**
     * Injects dependencies into the object. Override this method if you need
     * full control over how dependencies are injected.
     * 
     * @param main
     *            object to inject dependencies into
     */
    protected void injectDependencies(Object main) {
        getApplicationContext().getBeanFactory().autowireBeanProperties(
                main, AutowireCapableBeanFactory.AUTOWIRE_NO, false);
    }

    /**
     * Loads application context, then injects dependencies into the object.
     * 
     * @param main
     *            object to inject dependencies into
     * @param configLocations
     *            configuration file locations
     */
    public void load(Object main, String... configLocations) {
        loadApplicationContext(configLocations);
        injectDependencies(main);
    }
}

load在应用程序main方法中调用该方法.请注意,Main该类不是Spring创建的bean,但您可以使用应用程序上下文中的bean注入其中一个属性.

public class Main {
    @Autowired
    private SampleService sampleService;

    public static void main(String[] args) {
        Main main = new Main();
        new ApplicationContextLoader().load(main, "applicationContext.xml");
        main.sampleService.getHelloWorld();
    }
}