No qualifying bean of type [java.lang.String] is defined: expected single matching bean but found 2-蒲公英云

No qualifying bean of type [java.lang.String] is defined: expected single matching bean but found 2

墨蓝 2023-10-03 18:31 87阅读 0赞

错误信息：

No qualifying bean of type [java.lang.String] is defined: expected single matching bean but found 2: appclientApplication,slfclientApplication

具体场景：
service

@Resource
    private String appclientApplicationName;
    @Resource
    private String slfclientApplicationName;

xml

<bean id="appclientApplicationName " class="java.lang.String"> 
    <constructor-arg value="${Application}"/> 
</bean> 
<!-- 图片样式名 --> 
<bean id="slfclientApplicationName " class="java.lang.String"> 
    <constructor-arg value="${Application}"/> 
</bean>

结果在项目启动时报错：

No qualifying bean of type [java.lang.String] is defined: expected single matching bean but found 2: appclientApplication,slfclientApplication

原因：
因为我在使用@Resource注解时，并没有指定name属性，所以spring通过反射机制使用byName自动注入策略，将配置文件的value值注入了，而不是id值，这就导致spring找到了两个同样的value值，无法选择注入哪一个，最终报错。

解决方案通过指定name属性：

@Resource(name="appclientApplicationName")
    private String appclientApplication;
    @Resource(name="slfclientApplicationName")
    private String slfclientApplication;