Spring依赖注入后行为实现
主要有两种方式:
专业从事成都网站设计、做网站,高端网站制作设计,小程序开发,网站推广的成都做网站的公司。优秀技术团队竭力真诚服务,采用html5+CSS3前端渲染技术,成都响应式网站建设,让网站在手机、平板、PC、微信下都能呈现。建站过程建立专项小组,与您实时在线互动,随时提供解决方案,畅聊想法和感受。
1.通过实现InitializingBean接口的afterPropertiesSet()方法,在方法中处理业务
2.在配置文件中配置init-method
实现方式1:InitializingBean
@Component
public class InitializingMyBean implements InitializingBean {
@Autowired
private UserRepository userRepository;
@Override
public void afterPropertiesSet() throws Exception {
System.out.println("》》》新增用户《《《 ");
User user =new User();
user.setName("admin");
user.setPassword("admin123");
user.setAge("23");
user.setSex("男");
User add = userRepository.save(user);
if(!StringUtils.isEmpty(add)){
System.out.println("新增用户成功!");
}else{
System.out.println("新增用户失败!");
}
}
}
2.配置文件 :init-method
xml version="1.0" encoding="UTF-8"?>DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN""http://www.springframework.org/dtd/spring-beans.dtd">
init-method="init">bean>beans>
3.两种方式的区别:
实现InitializingBean接口是直接调用afterPropertiesSet方法,比通过反射调用init-method指定的方法效率相对来说要高点。但是init-method方式消除了对spring的依赖
4.注意:如果在spring初始化bean的时候,如果该bean是实现了InitializingBean接口,并且同时在配置文件中指定了init- method,
* 系统则是先调用afterPropertiesSet方法,然后在调用init-method中指定的方法
5.InitializingBean和init-mthod同时执行的原理:
详见:org.springframework.beans.factory.support包下的抽象类AbstractAutowireCapableBeanFactory
主要处理代码如下:
/**
* Give a bean a chance to react now all its properties are set,
* and a chance to know about its owning bean factory (this object).
* This means checking whether the bean implements InitializingBean or defines
* a custom init method, and invoking the necessary callback(s) if it does.
* @param beanName the bean name in the factory (for debugging purposes)
* @param bean the new bean instance we may need to initialize
* @param mbd the merged bean definition that the bean was created with
* (can also be {@code null}, if given an existing bean instance)
* @throws Throwable if thrown by init methods or by the invocation process
* @see #invokeCustomInitMethod
*/
protected void invokeInitMethods(String beanName, final Object bean, RootBeanDefinition mbd)
throws Throwable {
//获取当前bean是否实现了InitializingMyBean接口,如果实现了就执行afterPropertiesSet方法
boolean isInitializingBean = (bean instanceof InitializingBean);
if (isInitializingBean && (mbd == null || !mbd.isExternallyManagedInitMethod("afterPropertiesSet"))) {
if (logger.isDebugEnabled()) {
logger.debug("Invoking afterPropertiesSet() on bean with name '" + beanName + "'");
}
if (System.getSecurityManager() != null) {
try {
AccessController.doPrivileged(new PrivilegedExceptionAction