Bean 作用域

1package io.datajek.spring.basics.movierecommendersystem.lesson8;
2
3import org.springframework.boot.SpringApplication;
4import org.springframework.boot.autoconfigure.SpringBootApplication;
5import org.springframework.context.ApplicationContext;
6
7@SpringBootApplication
8public class MovieRecommenderSystemApplication {
9
10	public static void main(String[] args) {
11		
12		// ApplicationContext 管理 Bean 及其依赖关系
13		ApplicationContext appContext = SpringApplication.run(MovieRecommenderSystemApplication.class, args);
14
15		// 从应用上下文中三次获取单例 Bean
16		ContentBasedFilter cbf1 = appContext.getBean(ContentBasedFilter.class);	
17		ContentBasedFilter cbf2 = appContext.getBean(ContentBasedFilter.class);	
18		ContentBasedFilter cbf3 = appContext.getBean(ContentBasedFilter.class);	
19					
20		System.out.println(cbf1);
21		System.out.println(cbf2);
22		System.out.println(cbf3);
23	}
24}

声明原型作用域的两种方法

1// 方法一
2@Scope("prototype")
3
4// 方法二
5@Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)

应用上下文在 main() 方法中管理 Bean 和依赖关系

1public static void main(String[] args) {
2    // ApplicationContext 管理 Bean 及其依赖关系
3    ApplicationContext appContext = SpringApplication.run(MovieRecommenderSystemApplication.class, args);
4
5    // ...
6
7    // 从应用上下文中三次获取原型 Bean
8    CollaborativeFilter cf1 = appContext.getBean(CollaborativeFilter.class);	
9    CollaborativeFilter cf2 = appContext.getBean(CollaborativeFilter.class);	
10    CollaborativeFilter cf3 = appContext.getBean(CollaborativeFilter.class);
11
12    System.out.println(cf1);
13    System.out.println(cf2);
14    System.out.println(cf3);
15}

这次，应用上下文将返回三个不同的对象。每次调用 getBean() 方法时，都会创建一个新的实例。

1package io.datajek.spring.basics.movierecommendersystem.lesson8;
2
3import org.springframework.boot.SpringApplication;
4import org.springframework.boot.autoconfigure.SpringBootApplication;
5import org.springframework.context.ApplicationContext;
6
7@SpringBootApplication
8public class MovieRecommenderSystemApplication {
9
10	public static void main(String[] args) {
11		
12		// ApplicationContext 管理 Bean 及其依赖关系
13		ApplicationContext appContext = SpringApplication.run(MovieRecommenderSystemApplication.class, args);
14
15		// 从应用上下文中三次获取原型 Bean
16		CollaborativeFilter cf1 = appContext.getBean(CollaborativeFilter.class);	
17		CollaborativeFilter cf2 = appContext.getBean(CollaborativeFilter.class);	
18		CollaborativeFilter cf3 = appContext.getBean(CollaborativeFilter.class);
19				
20		System.out.println(cf1);
21		System.out.println(cf2);
22		System.out.println(cf3);
23	}
24}

1package io.datajek.spring.basics.movierecommendersystem.lesson8;
2
3import org.springframework.boot.SpringApplication;
4import org.springframework.boot.autoconfigure.SpringBootApplication;
5import org.springframework.context.ApplicationContext;
6
7@SpringBootApplication
8public class MovieRecommenderSystemApplication {
9
10	public static void main(String[] args) {
11		
12		// ApplicationContext 管理 Bean 及其依赖关系
13		ApplicationContext appContext = SpringApplication.run(MovieRecommenderSystemApplication.class, args);
14
15		// 从应用上下文中三次获取单例 Bean
16		// ContentBasedFilter cbf1 = appContext.getBean(ContentBasedFilter.class);	
17		// ContentBasedFilter cbf2 = appContext.getBean(ContentBasedFilter.class);	
18		// ContentBasedFilter cbf3 = appContext.getBean(ContentBasedFilter.class);	
19					
20		// 从应用上下文中三次获取原型 Bean
21		// CollaborativeFilter cf1 = appContext.getBean(CollaborativeFilter.class);	
22		// CollaborativeFilter cf2 = appContext.getBean(CollaborativeFilter.class);	
23		// CollaborativeFilter cf3 = appContext.getBean(CollaborativeFilter.class);
24	}
25}