MyBatis 售后咨询

org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: java.lang.UnsupportedOperationException
### The error may exist in test/myproj/mapper/BlogMapper.java (best guess)
### The error may involve defaultParameterMap
### The error occurred while setting parameters
### SQL: select * from blog
### Cause: java.lang.UnsupportedOperationException
    at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:23)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:104)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:95)
    at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:124)
    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:90)
    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:40)
    at $Proxy8.selectAll(Unknown Source)
    at test.myproj.MyMvnTest.MvnTest.doMain(MvnTest.java:40)
    at test.myproj.MyMvnTest.MvnTest.main(MvnTest.java:23)
Caused by: java.lang.UnsupportedOperationException
    at org.apache.ibatis.reflection.wrapper.CollectionWrapper.set(CollectionWrapper.java:38)
    at org.apache.ibatis.reflection.MetaObject.setValue(MetaObject.java:140)
    at org.apache.ibatis.executor.resultset.FastResultSetHandler.applyPropertyMappings(FastResultSetHandler.java:299)
    at org.apache.ibatis.executor.resultset.FastResultSetHandler.getRowValue(FastResultSetHandler.java:264)
    at org.apache.ibatis.executor.resultset.FastResultSetHandler.handleRowValues(FastResultSetHandler.java:214)
    at org.apache.ibatis.executor.resultset.FastResultSetHandler.handleResultSet(FastResultSetHandler.java:186)
    at org.apache.ibatis.executor.resultset.FastResultSetHandler.handleResultSets(FastResultSetHandler.java:152)
    at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:57)
    at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:70)
    at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:57)
    at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:267)
    at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:141)
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:105)
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:81)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:101)
    ... 7 more

这是用注释写的一个测试程序，但是出了这样的错误，错误的原因很简单是因为返回的List（红色标注）中没有指定泛型对象。

package test.myproj.mapper;

import java.util.List;

import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;

import test.myproj.model.Blog;

public interface BlogMapper {
    
    @Select("select * from blog")
    @Results({
        @Result(property="id", column="id"),
        @Result(property="title", column="title"),
        @Result(property="content", column="content")
    })
    List<Blog> selectAll();
}