java - 在运行时选择 spring bean

Question

我在选择应该注入(inject)的正确 spring bean 时遇到问题。 我需要一种方法来告诉 spring 容器根据对前一个类的调用注入(inject)什么 bean。我在 xml 中完成所有 Spring bean 连接。

我的问题:这可能吗？它是否对实现有任何引用？

我创建了一些示例代码来说明我想要完成的任务。请随意更改它，以便在运行时根据所选的报告类型注入(inject)正确的 ReportHeader bean。

public enum ReportType{
    Credit,
    Annul   
}

public class ReportService {

    private ReportHeaderService reportHeaderService;
    private ReportType reportType;

    public ReportService (){}

    public setReportType(ReportType reportType){
        this.reportType = reportType;
    }

    public void setReportHeaderService(ReportHeaderService reportHeaderService){
        this.reportHeaderService = reportHeaderService;
    }

    private void generateHeader(){
        //i would like to call my service like this and have the correct bean injected to ReportHeader.
        reportHeaderService.generateHeader(reportType)
    }
}

public class ReportHeaderService {

    private ReportHeader reportHeader;

    //this will call the injected bean that needs to be selected accoring to the ReportType
    public void generateHeader(ReportType type){
        reportHeader.createHeader();
    }
}

public interface ReportHeader{
    public void createHeader();
}

public class CreditReportHeader implements ReportHeader{
    public void createHeader(){
        ..dostuff();
    }
}

public class AnnulReportHeader implements ReportHeader{
    public void createHeader(){
        ..dostuff();
    }
}

Answer 1

考虑注入(inject) Map<ReportType, ReportHeader>到 ReportHeaderService，以便generateHeader 的工作方式如下:

public class ReportHeaderService {

    private Map<ReportType, ReportHeader> reportHeaderMap;

    public void generateHeader(ReportType type){
        ReportHeader reportHeader = reportHeaderMap.get(type);
        if (reportHeader != null) {
            reportHeader.createHeader();
        }
    }
}