Spring启动过程中创建bean过程中自动注入部分的代码分析

//这里为什么要有取出属性值的一步？
//因为在 BeanDefinition的后置处理 那一步我可能已经对某个属性进行赋值了，后面的对属性进行赋值的就应该要检查避免进行覆盖。
PropertyValues pvs = (mbd.hasPropertyValues() ? mbd.getPropertyValues() : null);

int resolvedAutowireMode = mbd.getResolvedAutowireMode();
if (resolvedAutowireMode == AUTOWIRE_BY_NAME || resolvedAutowireMode == AUTOWIRE_BY_TYPE) {
    // MutablePropertyValues是PropertyValues具体的实现类
    MutablePropertyValues newPvs = new MutablePropertyValues(pvs);
    // Add property values based on autowire by name if applicable.
    if (resolvedAutowireMode == AUTOWIRE_BY_NAME) {
        autowireByName(beanName, mbd, bw, newPvs);
    }
    // Add property values based on autowire by type if applicable.
    if (resolvedAutowireMode == AUTOWIRE_BY_TYPE) {
        autowireByType(beanName, mbd, bw, newPvs);
    }
    pvs = newPvs;
}