如何在沒有XML檔案且僅使用Java的情況下配置Spring專案？

我目前正在學習 Spring 框架。

我創建了 1 個 Bean 物件（類和介面）和 1 個依賴項（介面和類）。當我嘗試在沒有 xml 檔案和純 Java 類的情況下配置 Spring Beans 時，出現以下錯誤：

Exception in thread "main" org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'swimCoach' available
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:863)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1344)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:309)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:213)
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1160)
    at com.mandeep.spring.JavaConfigApp.main(JavaConfigApp.java:14)

Spring配置類“SportConfig.java”如下：

package com.mandeep.spring;


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

@Configuration
//@ComponentScan("com.mandeep.spring")
public class SportConfig {
    
    //Define a Method for SadFortuneService
    @Bean
    public FortuneService sadFortuneService() {
        return new SadFortuneService();
    }
    
    //Define a Method for SwimCoach and Inject Dependency
    @Bean
    public Coach swimCoach() {
        return new SwimCoach(sadFortuneService());
    }
}

主函式類“JavaConfigApp.java”如下：

package com.mandeep.spring;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class JavaConfigApp {

    public static void main(String[] args) {
        
        //Read Spring Config. File
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext("SportConfig.class");
        
        
        //Get Bean From Spring Container
        Coach theCoach = context.getBean("swimCoach",Coach.class);
        
        //Call Method from the Bean
        System.out.println(theCoach.getDailyWorkout());
        
        System.out.println(theCoach.getDailyFortune());
        
        
        
        //Close the Context
        context.close();        
    }

}

“SwimCoach.java”類實作了Coach介面，如下：

package com.mandeep.spring;


public class SwimCoach implements Coach {

    private FortuneService fortuneService;
    
    public SwimCoach(FortuneService fortuneService) {
        super();
        this.fortuneService = fortuneService;
    }

    @Override
    public String getDailyWorkout() {
        
        return "Swim For 100 rounds";
    }

    @Override
    public String getDailyFortune() {
        
        return fortuneService.getFortune();
    }

    @Override
    public String getEmail() {
        
        return null;
    }

}

依賴類“SadFortuneService.java”實作了FortuneService介面，如下：

package com.mandeep.spring;


public class SadFortuneService implements FortuneService {

    @Override
    public String getFortune() {
        
        return "Today is your Bad Luck";
    }

}

uj5u.com熱心網友回復：

嘗試使用組件類來構建你的背景關系

AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(SportConfig.class);

使用 basePackages 時，我們應該添加要掃描的包的完整路徑。

uj5u.com熱心網友回復：

嘗試掃描包：

AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
context.scan("com.mandeep.spring");

標籤：爪哇 春天 弹簧靴 蚀 弹簧MVC

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