Mybatis中怎么使用if语句

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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                      

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