mybatis. java.lang.UnsupportedOperationException

Question

Why an error occurs in this code? I don't understand.. Help me please.

I've tested it: doSave(), getListCount(), doDelete(), getDetails() are good.

But, in getList() method an error occurs!

Why? That method has no parameters, only one query.

select * from tb_board_data

my config : mybatis 3.2.2 / mybatis-spring 1.2.0 / spring 3.2.2

package kr.co.goodwilldd.board.mapper;

import java.util.ArrayList;

import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.SelectKey;
import org.apache.ibatis.mapping.StatementType;
import org.springframework.stereotype.Repository;

@Repository
public interface CommonBoardMapper<T> {

    @Select(value = "SELECT COUNT(*) FROM TB_BOARD_DATA")
    public long getListCount();

    @Select(value = "SELECT * FROM TB_BOARD_DATA")
    public ArrayList<T> getList();

    @Select(value = "SELECT * FROM TB_BOARD_DATA WHERE bseq = #{_seq}")
    public T getDetails(long _seq);

    @SelectKey(before=true, keyProperty="bseq", statementType=StatementType.PREPARED, statement="SELECT (IFNULL(MAX(BSEQ),0)+1) as bseq FROM TB_BOARD_DATA", resultType=Long.class)
    @Insert(value = "INSERT INTO TB_BOARD_DATA(bseq, boardName, register, subject, content, reStep, reLevel, regdate) SELECT #{bseq}, #{boardName}, #{register}, #{subject}, #{content}, ifnull(((floor(max(reStep)/100))+1)*100+99, 199) , 0, CURRENT_DATE() FROM TB_BOARD_DATA")
    public int doSave(T t);

    @Delete(value = "DELETE FROM TB_BOARD_DATA WHERE bseq = #{_seq}")
    public int doDelete(long _seq);
}

Error logs here:

org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: java.lang.UnsupportedOperationException
### The error may exist in kr/co/goodwilldd/board/mapper/CommonBoardMapper.java (best guess)
### The error may involve defaultParameterMap
### The error occurred while setting parameters
### SQL: SELECT * FROM TB_BOARD_DATA
### Cause: java.lang.UnsupportedOperationException
    at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:73)
    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:364)
    at com.sun.proxy.$Proxy13.selectList(Unknown Source)
    at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:194)
    at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:114)
    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:58)
    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:43)
    at com.sun.proxy.$Proxy25.getList(Unknown Source)
    at kr.co.goodwilldd.board.CommonBoardTest.getListByMapper(CommonBoardTest.java:31)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:88)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: java.lang.UnsupportedOperationException
### The error may exist in kr/co/goodwilldd/board/mapper/CommonBoardMapper.java (best guess)
### The error may involve defaultParameterMap
### The error occurred while setting parameters
### SQL: SELECT * FROM TB_BOARD_DATA
### Cause: java.lang.UnsupportedOperationException
    at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:23)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:107)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:98)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:354)
    ... 36 more
Caused by: java.lang.UnsupportedOperationException
    at org.apache.ibatis.reflection.wrapper.CollectionWrapper.findProperty(CollectionWrapper.java:42)
    at org.apache.ibatis.reflection.MetaObject.findProperty(MetaObject.java:76)
    at org.apache.ibatis.executor.resultset.FastResultSetHandler.applyAutomaticMappings(FastResultSetHandler.java:342)
    at org.apache.ibatis.executor.resultset.FastResultSetHandler.getRowValue(FastResultSetHandler.java:267)
    at org.apache.ibatis.executor.resultset.FastResultSetHandler.handleRowValues(FastResultSetHandler.java:216)
    at org.apache.ibatis.executor.resultset.FastResultSetHandler.handleResultSet(FastResultSetHandler.java:188)
    at org.apache.ibatis.executor.resultset.FastResultSetHandler.handleResultSets(FastResultSetHandler.java:154)
    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.ReuseExecutor.doQuery(ReuseExecutor.java:54)
    at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:259)
    at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:132)
    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:104)
    ... 42 more

Solution

You should specify a concrete type as the return type, like

List<Customer> getList();

, but no generic type

List<T> getList();

or

List getList();

Cause if you specify the type, mybatis will use BeanWrapper convert each row to the type. But if there are no specific type, mybatis will treat each row as a List and use CollectionWrapper, which findProperty is not supported.