spring map使用annotation泛型注入问题分析

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今天在整一个spring的ioc学习demo，碰到一个问题，居然@Autowire在set方法注入map时，map的key类型不能为String之外的其他类型，具体看下面问题

@Autowiredpublic void setTypeMap(Map<Integer,String> typeMap) {this.typeMap = typeMap;}

xml注入配置，即时在map上加上key和value的类型也不行。

      <property name="typeMap">         <map key-type="java.lang.Integer" value-type="String">            <entry key="1">               <value>COO)</value>            </entry>            <entry key="2">               <value>CFO</value>            </entry>            <entry key="3">               <value>CEO</value>            </entry>         </map>      </property>

报错：

Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire method: public void org.springweb.service.impl.HelloServiceImpl.setTypeMap(java.util.Map); nested exception is org.springframework.beans.FatalBeanException: Key type [class java.lang.Integer] of map [java.util.Map] must be assignable to [java.lang.String]   at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:589)   at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:84)   at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:282)   ... 13 moreCaused by: org.springframework.beans.FatalBeanException: Key type [class java.lang.Integer] of map [java.util.Map] must be assignable to [java.lang.String]   at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:761)   at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:703)   at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:547)

查看spring的代码

   else if (Map.class.isAssignableFrom(type) && type.isInterface()) {         Class keyType = descriptor.getMapKeyType();         if (keyType == null || !String.class.isAssignableFrom(keyType)) {            if (descriptor.isRequired()) {               throw new FatalBeanException("Key type [" + keyType + "] of map [" + type.getName() +                     "] must be assignable to [java.lang.String]");            }            return null;         }

也就是spring使用Autowired进入注入时，map的key类型只能为string，但是

如果我使用set方法注入后者构造方法注入，map的可以是可以自动转为integer的。

set方法注入，不要在set方法上使用antowired

public void setTypeMap(Map<Integer,String> typeMap) {this.typeMap = typeMap;}

//构造方法注入public HelloServiceImpl(String greetting,Map<Integer,String> typeMap){this.greetting = greetting;this.typeMap = typeMap;System.out.println("call HelloServiceImpl constructor" + this.greetting);}

<constructor-arg type="Map" index="1"><map><entry key="1"><value>COO</value></entry><entry key="2"><value>CFO</value></entry><entry key="3"><value>CEO</value></entry></map></constructor-arg>

可以参考http://forum.springsource.org/showthread.php?105558-Autowired-injection-of-a-Map