SpringBean的配置详解

• Bean的初始化和销毁方法配置
  • Bean在被实例化后，可以执行指定的初始化方法完成一些初始化的操作，Bean在销毁之前也可以执行指定的销毁方法完成一些操作，初始化方法名称和销毁方法名称通过

    •    <bean id="userService" name="aaa,bbb" class="com.example.Service.Impl.UserServiceImpl" init-method="init"
                destroy-method="destroy">

    • 指定的方法名于自己创建的方法名一致即可

      • package com.example.Service.Impl;
        
        import com.example.DAO.UserDAO;
        import com.example.Service.UserService;
        
        public class UserServiceImpl implements UserService {
        
            public void init() {
                System.out.println("初始化方法");
            }
        
            public void destroy() {
                System.out.println("销毁方法");
            }
        
            public UserServiceImpl() {
                System.out.println("UserServiceImpl实例化");
            }
        
            private UserDAO userDAO;
        
            public void setUserDAO(UserDAO userDAO) {
            }
        }
        

    • 测试类

      • package com.example.Test;
        
        import org.springframework.context.ApplicationContext;
        import org.springframework.context.support.ClassPathXmlApplicationContext;
        
        public class TestApplicationContext {
            public static void main(String[] args) {
                ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("application.xml");
                Object userService1 = context.getBean("userService");
                System.out.println(userService1);
                context.close();
        
            }
        }
        

    • 运行结果如下

      • 

拓展 

• 我们还可以通过实现InitializingBean接口，完成bean的初始化操作

  • package com.example.Service.Impl;
    
    import com.example.DAO.UserDAO;
    import com.example.Service.UserService;
    import org.springframework.beans.factory.InitializingBean;
    
    public class UserServiceImpl implements UserService, InitializingBean {
    
        public void init() {
            System.out.println("初始化方法");
        }
    
        public void destroy() {
            System.out.println("销毁方法");
        }
    
        public UserServiceImpl() {
            System.out.println("UserServiceImpl实例化");
        }
    
        private UserDAO userDAO;
    
        public void setUserDAO(UserDAO userDAO) {
        }
    
        // todo 执行时机早于init-method方法
        @Override
        public void afterPropertiesSet() throws Exception {
            System.out.println("InitializingBean.....");
        }
    }
    

  • 测试类运行结果如下

    •