Spring：地图无法自动连线问题

Question

@Component
public class BankServicesImpl implements BankServices {
    @Autowired
    private DataRepoImpl db;
}

----------------------------------------------------------------------------

@Component
public class DataRepoImpl implements DataRepo{
    private Map<Integer, Account> repo = new HashMap<Integer,Account>();
}

----------------------------------------------------------------------------

@Component
public class Account {
    private Integer accountID;
    private int balance;
}

代码完成了这项工作，创建了repo HashMap对象（{}）。然而，我试图让repo映射对象由Spring生成。所以我把DataRepoImpl改成：

@Component
public class DataRepoImpl implements DataRepo{
    @Autowired
    private Map<Integer, Account> repo;
}

Error:
Nov 08, 2021 11:37:06 PM org.springframework.context.support.AbstractApplicationContext refresh
WARNING: Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'dataRepoImpl': Unsatisfied dependency expressed through field 'repo'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'java.util.Map<java.lang.Integer, com.doubleliu.model.Account>' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
Exception in thread "main" org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'dataRepoImpl': Unsatisfied dependency expressed through field 'repo'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'java.util.Map<java.lang.Integer, com.doubleliu.model.Account>' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'java.util.Map<java.lang.Integer, com.doubleliu.model.Account>' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

然而，当我重构帐户ID和地图键到字符串类型，我能够产生HashMap包含一个'假人'变量，这是奇怪的：

{account=com.doubleliu.model.Account@397fbdb}

回到Integer，我无法修复错误，然后我尝试将自动连线移到DataRepoImpl类的空构造函数：

    @Autowired
    public DataRepoImpl() {
    }

然而，我从repo得到空值，因为（我的假设）对象尚未创建或分配给repo Map变量。然后，我再次将自动连线移动到以map为参数的构造函数上：

    @Autowired
    public DataRepoImpl(Map<Integer, Account> repo) {
        this.repo = repo;
    }

这次创建了repo对象（{}），并且不为null，我假设该对象是通过参数创建的，这是使用spring创建它的正确方法吗？此外，我的IDE将我标记为错误无法自动连线。没有豆子的地图

我刚刚开始学习spring，试图在进入下一个阶段之前完全理解它。因此，任何对代码的响应、解决方案、注释、建议、修复和问题都非常满意，尤其是autowired。非常感谢。

编辑：我正在使用基于xml注释的配置




Answer 1

和这里有关

我刚刚发现我需要在xml中定义定义的bean的属性。每次我定义HashMap之类的东西时，都会在xml中添加以下内容，这样我就可以通过在类中的Map变量上定义@Resource来注入刚刚定义的Map bean。

<util:map id="repo" scope="prototype" map-class="java.util.HashMap"
                  key-type="java.lang.String" value-type="com.doubleliu.model.Account"/>

感谢您的帮助和意见，欢迎您提出更多意见和建议。