How to use if statement in Mybatis
这篇文章给大家介绍Mybatis中怎么使用if语句，内容非常详细，感兴趣的小伙伴们可以参考借鉴，希望对大家能有所帮助。
一个参数情况DAO层Map selectPeriodByDataType(String dataType);XML文件
一个参数时，在if条件判断时，需要使用 _parameter 如果使用dataType,会报错如下
org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.reflection.ReflectionException: There is no getter for property named 'dataType' in 'class java.lang.String' at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:77) at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:446) at com.sun.proxy.$Proxy115.selectOne(Unknown Source) at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:166) at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:82) at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59) at com.sun.proxy.$Proxy155.selectPeriodByDataType(Unknown Source) at com.bjbde.trade.service.impl.WmsDictionaryDataServiceImpl.getBuyerRightsPeriod(WmsDictionaryDataServiceImpl.java:47) at com.bjbde.trade.service.impl.WmsDictionaryDataServiceImpl$$FastClassBySpringCGLIB$$b29775c3.invoke()解决方案
方案一
${alias}.DATA_VALUE dataValue SELECT FROM WMS_DICTIONARY_DATA t1 WHERE t1.IS_VALID = '1' AND t1.DATA_NAME = 'data_period' AND t1.DATA_NAME = 'api_period' AND t1.DATA_NAME = 'analysis_period' AND t1.DATA_NAME = 'model_period'
if中的test使用单引号，dataType参数对应的为字符串，需要使用""来引起来。
方案二
${alias}.DATA_VALUE dataValue SELECT FROM WMS_DICTIONARY_DATA t1 WHERE t1.IS_VALID = '1' /*AND t1.DATA_NAME = 'data_period'*/ AND t1.DATA_NAME = 'data_period' AND t1.DATA_NAME = 'api_period' AND t1.DATA_NAME = 'analysis_period' AND t1.DATA_NAME = 'model_period'
dataType对应的参数需要加上toString()方法，否则会将该值当做数字，从而找不到满足要求的条件。
多个参数情况DAO层 List selectDataProductList(DataProductListVO vo);POJO类DataProductListVO@Builder@Datapublic class DataProductListVO implements Serializable { private static final long serialVersionUID = -6905484517733433984L; //页码 默认值0 private Integer page = 0; //页长 默认值0 private Integer size = 0; private String industry; private String ownership; private String salNum; private String wiVal; private String name; private String tag; private String address; private String pubTime; private String comment; private String type;}
多个参数时，常将参数封装成对象来处理。
xml文件 ${alias}.DATA_ID,${alias}.NAME,${alias}.SH_IMG,${alias}.TYP PRODUCT_TYP,${alias}.INDUSTRY,${alias}.RANGE,${alias}.OWNERSHIP,${alias}.TRADING,${alias}.LABELS,${alias}.LINK_MAN,${alias}.LINK_PHONE,${alias}.PRICE,${alias}.HAS_SPEC,${alias}.SPEC,${alias}.WDESC,${alias}.PUB_TIME,${alias}.COMMENT_SCORE,${alias}.SALED_NUM,${alias}.VIEW_NUM,${alias}.FAVORITY_NUM,${alias}.WSTATE,${alias}.MBR_ID,${alias}.DEFAULT_WI select from PSM_DATA_BASE t1 where t1.WSTATE = '01' AND t1.NAME like '%${name}%' AND t1.TYP = '%${type}%' AND t1.RANGE like '%${RANGE}%' AND t1.INDUSTRY like '%${industry}%' AND t1.LABELS like '%${tag}%' AND t1.OWNERSHIP like '%${ownership}%' order by t1.SALED_NUM asc t1.SALED_NUM desc t1.DEFAULT_WI asc t1.DEFAULT_WI desc t1.PUB_TIME asc t1.PUB_TIME desc t1.COMMENT_SCORE asc t1.COMMENT_SCORE desc t1.DEFAULT_WI asc 关于Mybatis中怎么使用if语句就分享到这里了，希望以上内容可以对大家有一定的帮助，可以学到更多知识。如果觉得文章不错，可以把它分享出去让更多的人看到。
