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以下出现的第一个入参boolean condition
表示该条件是否加入最后生成的SQL中,例如:
query.like(StringUtils.isNotBlank(name), Entity::getName, name)
.eq(age!=null && age >= 0, Entity::getAge, age)
以下代码块内的多个方法均为从上往下补全个别boolean
类型的入参,默认为true
,如:
以下出现的泛型Param
均为Wrapper
的子类实例(均具有AbstractWrapper
的所有方法)
以下方法在入参中出现的R
为泛型,在普通wrapper中是String
,在LambdaWrapper中是函数(例:Entity::getId
,Entity
为实体类,getId
为字段id
的getMethod)
R column
均表示数据库字段,当R
具体类型为String
时则为数据库字段名(字段名是数据库关键字的自己用转义符包裹!)!而不是实体类数据字段名!!!,另当R
具体类型为SFunction
时项目runtime不支持eclipse自家的编译器!!!Map
和List
的均以json
形式表现!Map
或者List
为空,则不会加入最后生成的sql中!!!不支持以及不赞成在 RPC 调用中把 Wrapper 进行传输:
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 :::
allEq(Map<R, V> params)
allEq(Map<R, V> params, boolean null2IsNull)
allEq(boolean condition, Map<R, V> params, boolean null2IsNull)
params
: key
为数据库字段名,value
为字段值
null2IsNull
: 为true
则在map
的value
为null
时调用 isNull 方法,为false
时则忽略value
为null
的
allEq({id:1,name:"老王",age:null})
—>id = 1 and name = '老王' and age is null
allEq({id:1,name:"老王",age:null}, false)
—>id = 1 and name = '老王'
allEq(BiPredicate<R, V> filter, Map<R, V> params)
allEq(BiPredicate<R, V> filter, Map<R, V> params, boolean null2IsNull)
allEq(boolean condition, BiPredicate<R, V> filter, Map<R, V> params, boolean null2IsNull)
filter
: 过滤函数,是否允许字段传入比对条件中
params
与 null2IsNull
: 同上
allEq((k,v) -> k.indexOf("a") >= 0, {id:1,name:"老王",age:null})
—>name = '老王' and age is null
allEq((k,v) -> k.indexOf("a") >= 0, {id:1,name:"老王",age:null}, false)
—>name = '老王'
等于 =
eq(R column, Object val)
eq(boolean condition, R column, Object val)
eq("name", "老王")
—>name = '老王'
ne(R column, Object val)
ne(boolean condition, R column, Object val)
ne("name", "老王")
—>name <> '老王'
gt(R column, Object val)
gt(boolean condition, R column, Object val)
gt("age", 18)
—>age > 18
ge(R column, Object val)
ge(boolean condition, R column, Object val)
ge("age", 18)
—>age >= 18
lt(R column, Object val)
lt(boolean condition, R column, Object val)
lt("age", 18)
—>age < 18
le(R column, Object val)
le(boolean condition, R column, Object val)
le("age", 18)
—>age <= 18
between(R column, Object val1, Object val2)
between(boolean condition, R column, Object val1, Object val2)
between("age", 18, 30)
—>age between 18 and 30
notBetween(R column, Object val1, Object val2)
notBetween(boolean condition, R column, Object val1, Object val2)
notBetween("age", 18, 30)
—>age not between 18 and 30
like(R column, Object val)
like(boolean condition, R column, Object val)
like("name", "王")
—>name like '%王%'
notLike(R column, Object val)
notLike(boolean condition, R column, Object val)
notLike("name", "王")
—>name not like '%王%'
likeLeft(R column, Object val)
likeLeft(boolean condition, R column, Object val)
likeLeft("name", "王")
—>name like '%王'
likeRight(R column, Object val)
likeRight(boolean condition, R column, Object val)
likeRight("name", "王")
—>name like '王%'
isNull(R column)
isNull(boolean condition, R column)
isNull("name")
—>name is null
isNotNull(R column)
isNotNull(boolean condition, R column)
isNotNull("name")
—>name is not null
字段 IN (value.get(0), value.get(1), …)
in(R column, Collection<?> value)
in(boolean condition, R column, Collection<?> value)
in("age",{1,2,3})
—>age in (1,2,3)
in(R column, Object... values)
in(boolean condition, R column, Object... values)
字段 IN (v0, v1, …)
in("age", 1, 2, 3)
—>age in (1,2,3)
notIn(R column, Collection<?> value)
notIn(boolean condition, R column, Collection<?> value)
notIn("age",{1,2,3})
—>age not in (1,2,3)
notIn(R column, Object... values)
notIn(boolean condition, R column, Object... values)
notIn("age", 1, 2, 3)
—>age not in (1,2,3)
inSql(R column, String inValue)
inSql(boolean condition, R column, String inValue)
inSql("age", "1,2,3,4,5,6")
—>age in (1,2,3,4,5,6)
inSql("id", "select id from table where id < 3")
—>id in (select id from table where id < 3)
notInSql(R column, String inValue)
notInSql(boolean condition, R column, String inValue)
notInSql("age", "1,2,3,4,5,6")
—>age not in (1,2,3,4,5,6)
notInSql("id", "select id from table where id < 3")
—>id not in (select id from table where id < 3)
groupBy(R... columns)
groupBy(boolean condition, R... columns)
groupBy("id", "name")
—>group by id,name
排序:ORDER BY 字段, … ASC
orderByAsc(R... columns)
orderByAsc(boolean condition, R... columns)
orderByAsc("id", "name")
—>order by id ASC,name ASC
orderByDesc(R... columns)
orderByDesc(boolean condition, R... columns)
orderByDesc("id", "name")
—>order by id DESC,name DESC
orderBy(boolean condition, boolean isAsc, R... columns)
orderBy(true, true, "id", "name")
—>order by id ASC,name ASC
having(String sqlHaving, Object... params)
having(boolean condition, String sqlHaving, Object... params)
having("sum(age) > 10")
—>having sum(age) > 10
having("sum(age) > {0}", 11)
—>having sum(age) > 11
func(Consumer<Children> consumer)
func(boolean condition, Consumer<Children> consumer)
func(i -> if(true) {i.eq("id", 1)} else {i.ne("id", 1)})
or()
or(boolean condition)
or
表示紧接着下一个方法不是用and
连接!(不调用or
则默认为使用and
连接)
:::eq("id",1).or().eq("name","老王")
—>id = 1 or name = '老王'
or(Consumer<Param> consumer)
or(boolean condition, Consumer<Param> consumer)
or(i -> i.eq("name", "李白").ne("status", "活着"))
—>or (name = '李白' and status <> '活着')
and(Consumer<Param> consumer)
and(boolean condition, Consumer<Param> consumer)
and(i -> i.eq("name", "李白").ne("status", "活着"))
—>and (name = '李白' and status <> '活着')
nested(Consumer<Param> consumer)
nested(boolean condition, Consumer<Param> consumer)
nested(i -> i.eq("name", "李白").ne("status", "活着"))
—>(name = '李白' and status <> '活着')
apply(String applySql, Object... params)
apply(boolean condition, String applySql, Object... params)
该方法可用于数据库函数
动态入参的params
对应前面applySql
内部的{index}
部分.这样是不会有sql注入风险的,反之会有!
apply("id = 1")
—>id = 1
apply("date_format(dateColumn,'%Y-%m-%d') = '2008-08-08'")
—>date_format(dateColumn,'%Y-%m-%d') = '2008-08-08'")
apply("date_format(dateColumn,'%Y-%m-%d') = {0}", "2008-08-08")
—>date_format(dateColumn,'%Y-%m-%d') = '2008-08-08'")
last(String lastSql)
last(boolean condition, String lastSql)
last("limit 1")
exists(String existsSql)
exists(boolean condition, String existsSql)
exists("select id from table where age = 1")
—>exists (select id from table where age = 1)
notExists(String notExistsSql)
notExists(boolean condition, String notExistsSql)
notExists("select id from table where age = 1")
—>not exists (select id from table where age = 1)
::: tip 说明: 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 :::
select(String... sqlSelect)
select(Predicate<TableFieldInfo> predicate)
select(Class<T> entityClass, Predicate<TableFieldInfo> predicate)
wrapper
内的entity
属性有值!
这两类方法重复调用以最后一次为准
:::select("id", "name", "age")
select(i -> i.getProperty().startsWith("test"))
::: tip 说明:
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!
:::
set(String column, Object val)
set(boolean condition, String column, Object val)
set("name", "老李头")
set("name", "")
—>数据库字段值变为空字符串set("name", null)
—>数据库字段值变为null
setSql(String sql)
setSql("name = '老李头'")
LambdaWrapper
在QueryWrapper
中是获取LambdaQueryWrapper
在UpdateWrapper
中是获取LambdaUpdateWrapper
::: tip 注意事项:
需要mybatis-plus
版本 >= 3.0.7
param 参数名要么叫ew
,要么加上注解@Param(Constants.WRAPPER)
使用${ew.customSqlSegment}
不支持 Wrapper
内的entity生成where语句
:::
由于kotlin
相比于java
多了数据对象(data class
),在未说明情况下可能会混用。建议按照以下形式定义持久化对象
@TableName("sys_user")
class User {
@TableId(type = IdType.AUTO)
var id: Int? = null
@TableField("username")
var name: String? = null
var roleId: Int? = null
}
注意:这里的TableId
及TableField
并非必要,只是为了展示Mybatis-Plus
中的annotation
使用
这里所有成员都需要定义为可空类型(?
),并赋予null
的初始值,方便我们在以下场景中使用(类似java中的updateSelective
)
val wrapper = KtUpdateWrapper(User::class.java).eq(User::id, 2)
val newRecord = User()
newRecord.name = "newName"
userMapper!!.update(newRecord, wrapper)
不建议使用data class
及全参数构造方法,这样我们会写很多不必要的null
来构造一个空对象
@Select("select * from mysql_data ${ew.customSqlSegment}")
List<MysqlData> getAll(@Param(Constants.WRAPPER) Wrapper wrapper);
List<MysqlData> getAll(Wrapper ew);
<select id="getAll" resultType="MysqlData">
SELECT * FROM mysql_data ${ew.customSqlSegment}
</select>
// 区分:
// 链式调用 普通
UpdateChainWrapper<T> update();
// 链式调用 lambda 式。注意:不支持 Kotlin
LambdaUpdateChainWrapper<T> lambdaUpdate();
// 等价示例:
query().eq("id", value).one();
lambdaQuery().eq(Entity::getId, value).one();
// 等价示例:
update().eq("id", value).remove();
lambdaUpdate().eq(Entity::getId, value).remove();