mybatis报错：Caused by: java.lang.IllegalArgumentException: Caches collection already contains value fo...-优快云博客

本文详细解析了Eclipse环境下启动MyBatis应用时遇到的Cachecollectionalreadycontainsvalue错误，主要原因是mapper配置重复。文章提供了排查步骤，包括检查命名空间、别名及mapper文件，确保ID唯一性，最终解决启动问题。

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一、问题

eclipse启动时报下面的错误：

Caused by: java.lang.IllegalArgumentException: Caches collection already contains value for com.crm.dao.PaperUserMapper
    at org.apache.ibatis.session.Configuration$StrictMap.put(Configuration.java:782) ~[mybatis-3.2.7.jar:3.2.7]
    at org.apache.ibatis.session.Configuration$StrictMap.put(Configuration.java:754) ~[mybatis-3.2.7.jar:3.2.7]
    at org.apache.ibatis.session.Configuration.addCache(Configuration.java:516) ~[mybatis-3.2.7.jar:3.2.7]
    at org.apache.ibatis.builder.MapperBuilderAssistant.useNewCache(MapperBuilderAssistant.java:132) ~[mybatis-3.2.7.jar:3.2.7]
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.cacheElement(XMLMapperBuilder.java:209) ~[mybatis-3.2.7.jar:3.2.7]
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.configurationElement(XMLMapperBuilder.java:114) ~[mybatis-3.2.7.jar:3.2.7]
    ... 82 common frames omitted