mybatis条件查询容易遇见的错误

在使用mybatis的条件查询时，一不小心就容易出现这个错误：

19-Dec-2017 16:04:38.742 严重 [http-nio-8090-exec-6] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [SpringMVC] in context with path [] threw exception [Request processing failed; nested exception is org.mybatis.spring.MyBatisSystemException:
nested exception is org.apache.ibatis.reflection.ReflectionException: There is no getter for property named 'endoscopeType' in 'class java.lang.String'] with root cause

 org.apache.ibatis.reflection.ReflectionException: There is no getter for property named 'endoscopeType' in 'class java.lang.String'
at org.apache.ibatis.reflection.Reflector.getGetInvoker(Reflector.java:380)
at org.apache.ibatis.reflection.MetaClass.getGetInvoker(MetaClass.java:170)
at org.apache.ibatis.reflection.wrapper.BeanWrapper.getBeanProperty(BeanWrapper.java:152)
at org.apache.ibatis.reflection.wrapper.BeanWrapper.get(BeanWrapper.java:48)

这是mapper.xml文件：

<select id="findByEndoscopeType" resultMap="BaseResultMap" parameterType="java.lang.String">
SELECT *
FROM endoscope
<where>
<if test="endoscopeType != null">
endoscope_type = #{endoscopeType,jdbcType=VARCHAR}
</if>
</where>
</select>

出错的原因是因为加上 <if> 标签时，endoscope属性没有包含在String endoscopeType中，现有两种解决方法：

1.将<if>标签去掉；

2.传入参数放在对象中传进来；

<select id="findByEndoscopeType" resultMap="BaseResultMap" parameterType="com.iel.endoscope.entity.Endoscope">
SELECT *
FROM endoscope
<where>
<if test="endoscopeType != null">
endoscope_type = #{endoscopeType,jdbcType=VARCHAR}
</if>
</where>
</select>