[Code] occasionally take values, judge blanks, look up tables, verify, etc

Think about it or record it , Continuous follow-up , Convenient for subsequent reference

obtain List<String>

//  Get the table IDs duplicate removal 
List<String> tIds = list.stream()
.map(TableColumn::getTableParentId)
.distinct()
.collect(Collectors.toList());

//  Get the table IDs
List<String> tIds = tables.stream()
.map(Table::getId)
.collect(Collectors.toList());

//  Use List<Map>  Pay attention to case 
List<String> ids = params.stream()
.map(e -> e.get("id"))
.collect(Collectors.toList());

//  obtain Parameter.getCheckFormat
List<CheckFormat> checkFormat = Optional.ofNullable(parameter)
.map(u -> u.getCheckFormat())
.orElse(new ArrayList<>());

//  Get maximum 
FieldConfig maxFieldConfig = configs.stream()
.max(Comparator.comparing(FieldConfig::getOrderId))
.orElse(null);

Judgment parameters

//  Judge ： type 
if (type == null || !Arrays.asList("40", "60", "80").contains(type)) {
    String msg = " Select parameter type  40. library  60. surface  80. Field ";
    return TableUtil.getInstance().errorReturn(code, msg, msg);
}

//  Judge ： Use List<Map>,if(list != null && list.size() > 0) ===》》 CollectionUtils.isNotEmpty(list);
if (CollectionUtils.isEmpty(ruleList)) {
    String msg = " Rule not found ";
    return apiErrorReturn(500, msg, msg);
}

Table query

//  modify 
LambdaUpdateWrapper<Dir> dirUpdate = Wrappers.lambdaUpdate();
dirUpdate.set(Dir::getName, source.getCnName());
dirUpdate.eq(Dir::getType, 13);
dirUpdate.eq(Dir::getCode, source.getCode());
directoryMapper.update(new SsDir(), dirUpdate);

//  Inquire about 
List<Integer> ids = params.stream().map(QuotaBO::getId).collect(Collectors.toList());
LambdaQueryWrapper<QuotaBO> queryQuota = Wrappers.lambdaQuery();
queryQuota.eq(QuotaBO::getIsDelete, 0);
queryQuota.in(QuotaBO::getId, ids);
List<QuotaBO> quotaList = quotaMapper.getList(queryQuota);

//  Inquire about 
QueryWrapper qw = new QueryWrapper<>();
qw.eq("COLUMN_NAME", columnName);
List<ColumnBO> list = colService.getListByPage(qw, pIndex, pSize);

//  modify 
UpdateWrapper<ColumnBO> uw = new UpdateWrapper<>();
uw.eq("ID", column.getId());
List<ColumnBO> list = colService.getListByPage(column, uw);

Data De duplication

//  Use id To reprocess 
bloodList = bloodList.stream()
.collect(Collectors.collectingAndThen(Collectors.toCollection(() 
-> new TreeSet<>(Comparator.comparing(BloodBO::getId))), ArrayList::new));

Verify that... Exists

Don't add data repeatedly when there is data , When verifying whether the data already exists , Need to consider adding 、 modify （ When modifying, you need to ignore the existing conditions ）

select count(1) as valid, concat(' Classification number 【' ,#{itemId}, '】 Already exists ') as message from pig_item 
where IS_DELETE = 0 
and ITEM_ID = #{itemId} 
and (ID !=  #{idOld} or #{idOld} is null) 

<select id="checkVerifyItemNum" resultType="java.lang.Integer">
	<![CDATA[ select count(1) as valid from pig_item where IS_DELETE=0 and ITEM_ID = #{itemId} ]]>
	<if test="id != null">
	<![CDATA[ and (ID != #{id} or #{id} is null) ]]>
	</if>
</select>

<![CDATA[ Content ]]> The advantage of this writing method is not to escape if it is greater than or less than , It is inconvenient to write separately when judging the conditions

Multi-table query

Multiple table query ,left join down , The data is there , When there is more data , Query performance degradation .

with tmp_tab as ( 
	select  First query the data 
),
tmp_desc as (
	select  Look up the data  
) select * from tmp_desc