一、背景
mybatisPlus默認BaseMapper的分頁查詢方法返回的是PO對象，如果需要返回前端DTO或者VO類還需要在做一層轉換，非常麻煩
二、環境
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.2.0</version>
<exclusions>
<exclusion>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-generator</artifactId>
</exclusion>
</exclusions>
</dependency>
三、注入自定義sql
因爲只需要改造selectPage方法的返回值，那直接CV就好
- sql模板
public class SelectByPage extends AbstractMethod {
/**
* mapper 對應的方法名
*/
private static final String MAPPER_METHOD = "selectByPage";
@Override
public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
SqlMethod sqlMethod = SqlMethod.SELECT_PAGE;
String sql = String.format(sqlMethod.getSql(), sqlSelectColumns(tableInfo, true),
tableInfo.getTableName(), sqlWhereEntityWrapper(true, tableInfo),
sqlComment());
SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
return this.addSelectMappedStatementForTable(mapperClass, MAPPER_METHOD, sqlSource, tableInfo);
}
}
- 注入sql
public class CustomerSqlInjector extends DefaultSqlInjector {
@Override
public List<AbstractMethod> getMethodList(Class<?> mapperClass) {
List<AbstractMethod> methodList = super.getMethodList(mapperClass);
methodList.add(new SelectByPage());
return methodList;
}
}
- 通用mapper
public interface CommonMapper<T> extends BaseMapper<T> {
<E> IPage<E> selectByPage(IPage<E> page, @Param(Constants.WRAPPER) Wrapper<T> queryWrapper);
}
- 通用Service
public class CommonServiceImpl<M extends CommonMapper<T>, T> extends ServiceImpl<M, T> {
public <E> IPage<E> selectByPage(IPage<E> page, Wrapper<T> wrapper) {
return baseMapper.selectByPage(page, wrapper);
}
}