MyBatis-Plus AbstractWrapper条件构造器

条件构造器AbstractWrapper是QueryWrapper(LambdaQueryWrapper) 和 UpdateWrapper(LambdaUpdateWrapper) 的父类
用于生成 sql 的 where 条件, entity 属性也用于生成 sql 的 where 条件
注意: entity 生成的 where 条件与 使用各个 api 生成的 where 条件没有任何关联行为

List<User> users = userDao.selectList(new QueryWrapper<User>().eq("real_name","王昭君"));
        
log.info("----------user:{}", users);

AbstractWrapper下的方法及使用

方法名	说明	使用
allEq(Map<R, V> params)	全部=(或个别isNull)	allEq(params,true)
eq	=	eq(“real_name”,“王昭君”)
ne	<>	ne(“nick_name”,“空想4”)
gt	>	gt(“age”,21)
ge	>=	ge(“age”,22)
lt	<	lt(“age”,22)
le	<=	le(“age”,21")
between	cloum between ? and ?	between(“age”,0,21)
notBetween	cloum between ? and ?	notBetween(“age”,0,21)
like	cloum like ‘%王%’	like(“real_name”,“王”)
notLike	not like ‘%王%’	notLike(“real_name”,“王”)
likeLeft	like ‘%王’	likeLeft(“real_name”,“昭”)
likeRight	like ‘王%’	likeRight(“real_name”,“昭”)
isNull	is null	isNull(“gender”)
isNotNull	is not null	isNotNull(“gender”)
in	in (1,2,3)	in(“nick_name”,lists)
notIn	age not in (1,2,3)	notIn(“nick_name”,lists)
inSql	age in (1,2,3,4,5,6)	inSql(“nick_name”,"‘空想4’,‘空想5’,‘空想6’")
notInSql	age not in (1,2,3,4,5,6)	notInSql(“nick_name”,"‘空想4’,‘空想5’,‘空想6’")
groupBy	group by id,name	groupBy(“nick_name”,“age”)
orderByAsc	order by id ASC,name ASC	orderByAsc(“nick_name”,“age”)
orderByDesc	order by id DESC,name DESC	orderByDesc(“age”)
orderBy	order by id ASC,name ASC	orderBy(true,true,“age”)
having	having sum(age) > 10	having(“sum(age) > 10”)
or	id = 1 or name = ‘老王’	eq(“nick_name”,“空想4”).or(i->i.eq(“age”,21) eq(“nick_name”,“空想4”).or().eq(“nick_name”,“空想5”)
and	and (name = ‘李白’ and status <> ‘活着’)	and(i->i.eq(“age”,21))
nested	(name = ‘李白’ and status <> ‘活着’)	nested(i->i.eq(“age”,21).eq(“nick_name”,“空想4”))
apply	id = 1	apply(“nick_name = ‘空想4’”)
last	最后添加多个以最后的为准，有sql注入风险	last(“limit 1”)
exists	拼接 EXISTS ( sql语句 )	exists(“select id from table where age = 1”)
notExists	拼接 NOT EXISTS ( sql语句 )	notExists(“select id from table where age = 1”)

QueryWrapper

继承自 AbstractWrapper ,自身的内部属性 entity 也用于生成 where 条件
及 LambdaQueryWrapper, 可以通过 new QueryWrapper().lambda() 方法获取

方法名	说明	使用
select	select(i -> i.getProperty().startsWith(“test”))	select(“id”, “name”, “age”)

UpdateWrapper

继承自 AbstractWrapper ,自身的内部属性 entity 也用于生成 where 条件
及 LambdaUpdateWrapper, 可以通过 new UpdateWrapper().lambda() 方法获取!

方法名	说明	使用
set	set(“name”, “老李头”)	set(“name”, “”)
setSql	setSql(“name = ‘老李头’”)	setSql(String sql)

自定义SQL使用Wrapper

方案一 注解方式 Mapper.java

@Select("select * from mysql_data ${ew.customSqlSegment}")
List<MysqlData> getAll(@Param(Constants.WRAPPER) Wrapper wrapper);

方案二 XML形式 Mapper.xml

<select id="getAll" resultType="MysqlData">
	SELECT * FROM mysql_data ${ew.customSqlSegment}
</select>