问题

我有一个关于在Flowable的服务任务中进行Spring Bean注入的问题，为什么只有这种带有静态修饰符的注入方式有效，它的逻辑是什么？

我必须在Flowable的Java服务任务中注入一个Spring Bean，并且我尝试了一些不同种类的注入方式，包括字段注入、构造函数注入和Setter注入，最终我发现带有静态修饰符的Setter注入对我有效，就像这样：

public class GetCurrentUserDlg implements JavaDelegate {
    private static PersonService personService;
    @Autowired
    public void setPersonService(PersonService personService) {
        this.personService = personService;
    }
    @Override
    public void execute(DelegateExecution execution) {
        personService.getCurrentUser();
    }
}

public class GetCurrentUserDlg implements JavaDelegate {
    private static PersonService personService;
    @Autowired
    public void setPersonService(PersonService personService) {
        this.personService = personService;
    }
    @Override
    public void execute(DelegateExecution execution) {
        personService.getCurrentUser();
    }
}

答案1

得分: 6

以下是翻译好的部分：

"While I can not answer your question, the following works fine for me:"（虽然我无法回答你的问题，但以下内容对我来说有效：）

public class SomeDelegate implements JavaDelegate {
    @Autowired
    private SomeBean bean;
    @Override
    public void execute(DelegateExecution execution) {
        System.out.println(this.bean);
    }
}

"The class is then used in the process via flowable:class="packages.SomeDelegate""（然后该类通过 flowable:class="packages.SomeDelegate" 在流程中使用。）

"But, be aware, that you may have problems with autowiring dependencies in the SomeBean bean. This dependencies are not injected when using the flowable:class attribute. In order for this to work you have to make the SomeDelegate a actual bean itself (e.g. via @Service) and use it in your process definition via flowable:delegateExpression="${someDelegate}""（但请注意，您可能会在SomeBean bean中自动装配依赖项时遇到问题。当使用flowable:class属性时，这些依赖项不会被注入。为了使其工作，您必须将SomeDelegate 自身变成一个实际的bean（例如通过 @Service），并在流程定义中使用它，方法是通过 flowable:delegateExpression="${someDelegate}"。）

"Example:"（示例：）

@Service("someDelegate")
public class SomeDelegate implements JavaDelegate {
...

和

<serviceTask id="doSomething" name="Do Something" flowable:delegateExpression="${someDelegate}"/>

（请注意，翻译中的 " 是HTML实体，表示双引号。）

public class SomeDelegate implements JavaDelegate {
    @Autowired
    private SomeBean bean;
    @Override
    public void execute(DelegateExecution execution) {
        System.out.println(this.bean);
    }
}

@Service("someDelegate")
public class SomeDelegate implements JavaDelegate {
...

<serviceTask id="doSomething" name="Do Something" flowable:delegateExpression="${someDelegate}"/>

答案2

得分: 0

应该像这样工作：

@Component
public class GetCurrentUserDlg implements JavaDelegate {
    @Autowired
    private PersonService personService;
    @Override
    public void execute(DelegateExecution execution) {
        personService.getCurrentUser();
    }
}
@Component
public class PersonService {
   // 它的方法
}

@Component
public class GetCurrentUserDlg implements JavaDelegate {
    @Autowired
    private PersonService personService;
    @Override
    public void execute(DelegateExecution execution) {
        personService.getCurrentUser();
    }
}
@Component
public class PersonService {
   // its methods
}