SpringBoot 使用 @Configuration 集中管理 Bean的实战步骤

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
/**
 * 全局Bean配置类：集中管理所有Bean对象
 */
@Configuration // 核心注解：标记为配置类
public class GlobalBeanConfig {
    // ==================== 1. 管理自定义 Bean ====================
    /**
     * 创建自定义 UserService Bean（也可以用 @Service 注解，这里演示配置类方式）
     * @return Bean 对象
     */
    @Bean // 方法名 userService 就是 Bean 的名称
    public UserService userService() {
        return new UserService();
    }
    // ==================== 2. 管理第三方工具类 Bean ====================
    /**
     * 注册线程池 Bean（第三方类，无法加 @Component，必须用配置类管理）
     */
    @Bean
    public ExecutorService threadPool() {
        return Executors.newFixedThreadPool(5);
    }
    // ==================== 3. 带依赖注入的 Bean ====================
    /**
     * 创建 OrderService Bean，依赖上面的 userService Bean
     */
    @Bean
    public OrderService orderService(UserService userService) { // 自动注入已注册的 Bean
        OrderService orderService = new OrderService();
        // 手动注入依赖
        orderService.setUserService(userService);
        return orderService;
    }
}

// 自定义业务类（无需加 @Service/@Component，由配置类统一注册）
public class UserService {
    public String getUserInfo() {
        return "用户信息：集中管理的Bean";
    }
}
public class OrderService {
    private UserService userService;
    public void setUserService(UserService userService) {
        this.userService = userService;
    }
    public String getOrderInfo() {
        return "订单信息，依赖：" + userService.getUserInfo();
    }
}

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
@RestController
public class TestController {
    // 注入配置类中创建的 Bean
    @Resource
    private UserService userService;
    @Resource
    private OrderService orderService;
    @Resource
    private ExecutorService threadPool;
    @GetMapping("/test")
    public String test() {
        // 测试自定义Bean
        System.out.println(userService.getUserInfo());
        // 测试依赖注入的Bean
        System.out.println(orderService.getOrderInfo());
        // 测试第三方Bean
        threadPool.execute(() -> System.out.println("线程池Bean执行成功"));
        return "Bean 集中管理测试成功";
    }
}

@Bean(name = "customUserService") // 指定Bean名称
public UserService userService() {
    return new UserService();
}

@Resource(name = "customUserService")
private UserService userService;

thread:
  core: 5

import org.springframework.beans.factory.annotation.Value;
@Configuration
public class ThreadPoolConfig {
    @Value("${thread.core}")
    private Integer corePoolSize;
    @Bean
    public ExecutorService threadPool() {
        return Executors.newFixedThreadPool(corePoolSize);
    }
}

@Bean(destroyMethod = "shutdown") // 指定销毁方法
public ExecutorService threadPool() {
    return Executors.newFixedThreadPool(5);
}