Spring详细讲解FactoryBean接口的使用

public class SimpleFactoryBean implements FactoryBean<Cat> {
    @Override
    public Cat getObject() throws Exception {
        // 创建Cat对象并且返回
        return new Cat("Tom");
    }
    @Override
    public Class<?> getObjectType() {
        return Cat.class;
    }
}

<bean class="com.text.registrar.SimpleFactoryBean" id="cat"></bean>

public class Cat {
    String name;
    public Cat(String name) {
        this.name = name;
    }
}

@SpringBootApplication
public class SpringbootApplication {
    public static void main(String[] args) {
        ConfigurableApplicationContext run = SpringApplication.run(SpringbootApplication.class, args);
    }
    // 等价于配置文件配置
    @Bean
    public SimpleFactoryBean catFactoryBean() {
        return new SimpleFactoryBean();
    }
}

public interface MyUserMapper {
    void select();
}

public class MapperFactoryBean implements FactoryBean {
    /**
     * 用于保存接口的全类名
     */
    private String className;
    public MapperFactoryBean(String className) {
        this.className = className;
    }
    @Override
    public Object getObject() throws Exception {
        Class<?> interfaceClass = Class.forName(className);
        // 生成动态代理对象返回
        Object proxyInstance = Proxy.newProxyInstance(MapperFactoryBean.class.getClassLoader(), new Class[]{interfaceClass}, new InvocationHandler() {
            @Override
            public Object invoke(Object o, Method method, Object[] objects) throws Throwable {
                // 获取当前方法名
                System.out.println(method.getName());
                if ("select".equals((method.getName()))) {
                    System.out.println(className + "动态代理对象的select方法被执行了！！");
                }
                return null;
            }
        });
        return proxyInstance;
    }
    @Override
    public Class<?> getObjectType() {
        try {
            Class<?> interfaceCLass = Class.forName(className);
            return interfaceCLass;
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        return null;
    }
}

@SpringBootApplication
public class SpringbootApplication {
    public static void main(String[] args) {
        ConfigurableApplicationContext run = SpringApplication.run(SpringbootApplication.class, args);
        run.getBean(MyUserMapper.class);
    }
    // 等价于配置文件配置
    @Bean
    public MapperFactoryBean mapperFactoryBean() {
        return new MapperFactoryBean("com.test.registrar.MyUserMapper");
    }
}