错误提示:
org.apache.ibatis.exceptions.PersistenceException:
Error querying database. Cause: java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for com.helloword.mapper.UserMapper.xml
Cause: java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for com.helloword.mapper.UserMapper.xml
at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:150)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:77)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:71)
at test.Test.main(Test.java:43)
Caused by: java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for com.helloword.mapper.UserMapper.xml
at org.apache.ibatis.session.Configuration$StrictMap.get(Configuration.java:888)
at org.apache.ibatis.session.Configuration.getMappedStatement(Configuration.java:721)
at org.apache.ibatis.session.Configuration.getMappedStatement(Configuration.java:714)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:147)
... 4 more
解决办法:
- 看到报错信息,猜测可能是因为配置文件中的配置有问题,先看看mybatis-config.xml中的配置是否正确,查看配置没有问题
- 查看UserMapper.xml中namespace的路径是否正确,检查没有问
- UerMapper.xml在com.helloword.mapper的包里面,但是此包显示的为空,将
UserMapper.xml映射文件移到实体类的包里面,并且修改一与二中的配置。测试
之后,还是报上述错误。
————————————–一万只草泥马———————————————
新的报错信息
org.apache.ibatis.exceptions.PersistenceException:
Error building SqlSession.
The error may exist in com/helloworld/model/UserMapper.xml
Cause: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: java.io.IOException: Could not find resource com/helloworld/model/UserMapper.xml
at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:52)
at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:36)
at test.Test.<clinit>(Test.java:30)
Caused by: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: java.io.IOException: Could not find resource com/helloworld/model/UserMapper.xml
at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:121)
at org.apache.ibatis.builder.xml.XMLConfigBuilder.parse(XMLConfigBuilder.java:99)
at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:50)
... 2 more
Caused by: java.io.IOException: Could not find resource com/helloworld/model/UserMapper.xml
at org.apache.ibatis.io.Resources.getResourceAsStream(Resources.java:114)
at org.apache.ibatis.io.Resources.getResourceAsStream(Resources.java:100)
at org.apache.ibatis.builder.xml.XMLConfigBuilder.mapperElement(XMLConfigBuilder.java:371)
at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:119)
... 4 more
Exception in thread “main” java.lang.NullPointerException
at test.Test.main(Test.java:41)
- 错误显示是:创建SqlSession的问题,并报出主方法的空指针错误。
- 解决办法:粗心,在mybatis配置文件的的配置路径中一个字母写错了