Support method injection when @Autowired(require=false) is used on mixed nullability args

[chenqimiao]

When @Autowired(require=false) on mixed nullability args method, I think IOC container shoud call this method to inject partially non-null parameters, but in fact the current code logic will ignore this method injection, for example :

	static class MixedNullableInjectionBean{
		public NonNullBean nonNullBean;
		public NullableBean nullableBean;

		@Autowired(required = false)
		public void nullabilityInjection(@Nullable NullableBean nullableBean, NonNullBean nonNullBean){
			if(nullableBean != null){
				this.nullableBean = nullableBean;
			}
			this.nonNullBean = nonNullBean;
		}
	}

	@Test
	public void testMethodInjectionWithMultiMixedNullableArgs(){
		bf.registerBeanDefinition("nonNullBean", new RootBeanDefinition(
				NonNullBean.class));
		bf.registerBeanDefinition("mixedNullableInjectionBean", new RootBeanDefinition(MixedNullableInjectionBean.class));
		MixedNullableInjectionBean mixedNullableInjectionBean = bf.getBean(MixedNullableInjectionBean.class);
		assertThat(mixedNullableInjectionBean.nonNullBean).isNotNull();
		assertThat(mixedNullableInjectionBean.nullableBean).isNull();
	}

I liberated the @Autowired(require=false) annotation on the nullabilityInjection method of MixedNullableInjectionBean, this method has two parameters, nullableBean and nonNullBean, as the name of the parameter means, I only register nonNullBean to DefaultListableBeanFactory, and then register MixedNullableInjectionBean .
I think the IOC container should invoke nullabilityInjection method to inject nonNullBean,
but in fact the current code logic will ignore this method injection, I have expressed the nullability of the parameter nullableBean, so, I think this parameter is null should not affect the overall method injection. I slightly adjusted the logic of method injection in this pr, what do you think? Thank you for your reading and looking forward to your reply.

[snicoll]

Good stuff, thanks again @chenqimiao

This was closed with the wrong issue reference: d0fc6dd