Example Analysis of General example in MyBatis Mapper

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MyBatis generic Mapper's generic example (sorting) Example example = new Example (TerminalType.class); / / Note: sorting uses the column name example.setOrderByClause ("TT_PROVIDERID DESC"); / / if other conditions are required / / handset type name / / conditional query uses the attribute name example.createCriteria (). AndEqualTo ("terminalName", "Metering Field Service Terminal"); / / manufacturer id greater than 3amp / example.createCriteria (). AndGreaterThan ("id", 3) List terminalTypeList = terminalTypeService.selectByExample (example); API / * * query collection * * @ param example-condition * @ return count * / List selectByExample (Object example); implementation class @ Override public List selectByExample (Object example) {return baseMapper.selectByExample (example);} MyBatis generic Mapper skill 1. Sort

Error code:

Example.orderBy (BaseEntity.Field.GMTUpdate + "desc")

The correct way:

1. By annotating @ OrderBy (value = "DESC")

2. Example.setOrderByClause ("GMT_UPDATE DESC"); note that here is the column name, not the attribute name.

Second, handle the null exception of oracle 3. The selectOne return value of mapper may be null

The results obtained should be judged by null.

4. Look at the code public interface SequenceMapper {@ Select ("select SEQ_$ {tableName} .nextval from dual") int getSequence (@ Param ("tableName") String tableName);} "General example example Analysis in MyBatis Mapper". Thank you for reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!