spring

1、bean配置的三种方式

（1）使用@Bean注解

package mybean;

public class MyBean {
    private String name = "大法师";

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

package mybean;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MySpring {
    @Bean
    public MyBean make() {
        return new MyBean();
    }
}　　

 public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        MyBean myBean = (MyBean) context.getBean("make");
        System.out.println(myBean.getName());//大法师
   }

applicationContext.xml中配置<context:component-scan base-package="mybean"/>

（2）使用XML配置bean

package mybean;

public class Animal {
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

 public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
       Animal animal = (Animal)context.getBean("animal");
        System.out.println(animal.getName());//小猫
   }

applicationContext.xml中配置
    <bean id="animal" class="mybean.Animal">
        <property name="name" value="小猫"></property>
    </bean>

（3）使用注解

package mybean;

import org.springframework.stereotype.Component;

@Component
public class MyHome {
    public void play() {
        System.out.println("这是我家");
    }

    public void run() {
        System.out.println("这不是我家");
    }
}

public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
       MyHome myHome = (MyHome)context.getBean("myHome");
        myHome.play();//这是我家
   }

applicationContext.xml中配置<context:component-scan base-package="mybean"/>

2、bean实例化的三种方式　　

　（1）普通构造方法创建　

package mybean;

public class User {
    public void working(){
        System.out.println("工作少年");
    }
}

public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
       User user = (User)context.getBean("user");
        user.working();//工作少年
   }

applicationContext.xml中配置
    <bean id="user" class="mybean.User">
    </bean>  

　（2）静态方法创建　

package mybean;

public class UserFactory {
    public static User getInstance() {
        return new User();
      }
}

public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
       User user = (User)context.getBean("user");
        user.working();//工作少年
   }

applicationContext.xml中配置
    <bean id="user" class="mybean.UserFactory" factory-method="getInstance">
	</bean>

　（3）实例工厂创建

package mybean;

public class UserFactory {
    public User getUser() {
        return new User();
      }
}

public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
       User user = (User)context.getBean("user");
        user.working();//工作少年
   }

applicationContext.xml中配置
    <bean id="userFactory" class="mybean.UserFactory"></bean>
	<bean id="user" factory-bean="userFactory" factory-method="getUser">
	</bean>