There is no getter for property named 'PRODUCT_ID' in 'class java.lang.String'

背景：心血来潮之际，准备搭建以下多月未曾碰触过的Mybatis框架，体验一番原生之美。殊不知能力有限，错误百出。特抒此文以纪念此坑。
问题：想在sql管理中来统一处理一些简单的判断，但是添加判断之后参数有问题。报如下错误：
报错：

Exception in thread "main" org.apache.ibatis.exceptions.PersistenceException:
### Error querying database.  Cause: org.apache.ibatis.reflection.ReflectionException: There is no getter for property named 'PRODUCT_ID' in 'class java.lang.String'
### Cause: org.apache.ibatis.reflection.ReflectionException: There is no getter for property named 'PRODUCT_ID' in 'class java.lang.String'
    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 www.daoimp.ProductDaoImp.findCode(ProductDaoImp.java:31)
    at www.test.Test.findCode(Test.java:47)
    at www.test.Test.main(Test.java:22)
Caused by: org.apache.ibatis.reflection.ReflectionException: There is no getter for property named 'PRODUCT_ID' in 'class java.lang.String'
    at org.apache.ibatis.reflection.Reflector.getGetInvoker(Reflector.java:377)
    at org.apache.ibatis.reflection.MetaClass.getGetInvoker(MetaClass.java:167)
    at org.apache.ibatis.reflection.wrapper.BeanWrapper.getBeanProperty(BeanWrapper.java:149)
    at org.apache.ibatis.reflection.wrapper.BeanWrapper.get(BeanWrapper.java:45)
    at org.apache.ibatis.reflection.MetaObject.getValue(MetaObject.java:113)
    at org.apache.ibatis.scripting.xmltags.DynamicContext$ContextMap.get(DynamicContext.java:89)
    at org.apache.ibatis.scripting.xmltags.DynamicContext$ContextAccessor.getProperty(DynamicContext.java:107)
    at org.apache.ibatis.ognl.OgnlRuntime.getProperty(OgnlRuntime.java:1657)
    at org.apache.ibatis.ognl.ASTProperty.getValueBody(ASTProperty.java:92)
    at org.apache.ibatis.ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170)
    at org.apache.ibatis.ognl.SimpleNode.getValue(SimpleNode.java:210)
    at org.apache.ibatis.ognl.ASTNotEq.getValueBody(ASTNotEq.java:49)
    at org.apache.ibatis.ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170)
    at org.apache.ibatis.ognl.SimpleNode.getValue(SimpleNode.java:210)
    at org.apache.ibatis.ognl.Ognl.getValue(Ognl.java:333)
    at org.apache.ibatis.ognl.Ognl.getValue(Ognl.java:413)
    at org.apache.ibatis.ognl.Ognl.getValue(Ognl.java:395)
    at org.apache.ibatis.scripting.xmltags.OgnlCache.getValue(OgnlCache.java:45)
    at org.apache.ibatis.scripting.xmltags.ExpressionEvaluator.evaluateBoolean(ExpressionEvaluator.java:29)
    at org.apache.ibatis.scripting.xmltags.IfSqlNode.apply(IfSqlNode.java:30)
    at org.apache.ibatis.scripting.xmltags.MixedSqlNode.apply(MixedSqlNode.java:29)
    at org.apache.ibatis.scripting.xmltags.DynamicSqlSource.getBoundSql(DynamicSqlSource.java:37)
    at org.apache.ibatis.mapping.MappedStatement.getBoundSql(MappedStatement.java:265)
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:79)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:104)
    ... 4 more

原因： 直接使用参数后异常那就用这种方式，没有什么说的出来的原因，能力还没有到给各位讲解的程度，先这样解决吧。

当前参数传递： 

解决方案：

至此：完美解决。