Conanan

# 3 条件构造器 Wrapper

Wrapper 接口的实现类如下

image-20191215012329811

# AbstractWrapper

说明:

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(不推荐)

需要指定数据库字段名称，容易出错

allEq(Map<R, V> params);
allEq(Map<R, V> params, boolean null2IsNull);
allEq(boolean condition, Map<R, V> params, boolean null2IsNull);

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);

全部eq(或个别isNull)

  • 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

  • filter : 过滤函数,是否允许字段传入比对条件中

例子（需转换 JSON 格式为 Map）：

// id = 1 and name = '老王' and age is null
allEq({id:1,name:"老王",age:null})

// id = 1 and name = '老王'
allEq({id:1,name:"老王",age:null}, false)

// name = '老王' and age is null
allEq((k,v) -> k.indexOf("a") >= 0, {id:1,name:"老王",age:null})

// `name = '老王'
allEq((k,v) -> k.indexOf("a") >= 0, {id:1,name:"老王",age:null}, false)

@Test
public void allEq() {
  HashMap<String, Object> map = new HashMap<>();
  map.put("user_name", "Tom Cat");
  map.put("email", "Tom@qq.com");
  map.put("age", null);
  // SELECT id,user_name,age,email FROM user WHERE (user_name = ? AND age IS NULL)
  List<User> list = this.userMapper.selectList(
    new QueryWrapper<User>()
    .allEq((k, v) -> k.contains("user_name") || k.contains("age"), map, true));
}

# eq🔥

eq(R column, Object val)
eq(boolean condition, R column, Object val)
  • 等于 =
  • 例: eq("name", "老王")--->name = '老王'

# ne🔥

ne(R column, Object val)
ne(boolean condition, R column, Object val)
  • 不等于 <>
  • 例: ne("name", "老王")--->name <> '老王'

# gt🔥

gt(R column, Object val)
gt(boolean condition, R column, Object val)
  • 大于 >
  • 例: gt("age", 18)--->age > 18

# ge🔥

ge(R column, Object val)
ge(boolean condition, R column, Object val)
  • 大于等于 >=
  • 例: ge("age", 18)--->age >= 18

# lt🔥

lt(R column, Object val)
lt(boolean condition, R column, Object val)
  • 小于 <
  • 例: lt("age", 18)--->age < 18

# le🔥

le(R column, Object val)
le(boolean condition, R column, Object val)
  • 小于等于 <=
  • 例: le("age", 18)--->age <= 18

# between🔥

between(R column, Object val1, Object val2)
between(boolean condition, R column, Object val1, Object val2)
  • BETWEEN 值1 AND 值2
  • 例: between("age", 18, 30)--->age between 18 and 30

# notBetween🔥

notBetween(R column, Object val1, Object val2)
notBetween(boolean condition, R column, Object val1, Object val2)
  • NOT BETWEEN 值1 AND 值2
  • 例: notBetween("age", 18, 30)--->age not between 18 and 30

# like🔥

like(R column, Object val)
like(boolean condition, R column, Object val)
  • LIKE '%值%'
  • 例: like("name", "王")--->name like '%王%'

# notLike

notLike(R column, Object val)
notLike(boolean condition, R column, Object val)
  • NOT LIKE '%值%'
  • 例: notLike("name", "王")--->name not like '%王%'

# likeLeft🔥

likeLeft(R column, Object val)
likeLeft(boolean condition, R column, Object val)
  • LIKE '%值'
  • 例: likeLeft("name", "王")--->name like '%王'

# likeRight

likeRight(R column, Object val)
likeRight(boolean condition, R column, Object val)
  • LIKE '值%'
  • 例: likeRight("name", "王")--->name like '王%'

# isNull🔥

isNull(R column)
isNull(boolean condition, R column)
  • 字段 IS NULL
  • 例: isNull("name")--->name is null

# isNotNull🔥

isNotNull(R column)
isNotNull(boolean condition, R column)
  • 字段 IS NOT NULL
  • 例: isNotNull("name")--->name is not null

# in🔥

in(R column, Collection<?> value)
in(boolean condition, R column, Collection<?> value)
  • 字段 IN (value.get(0), value.get(1), ...)
  • 例: 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, ...)
  • 例: in("age", 1, 2, 3)--->age in (1,2,3)

# notIn🔥

notIn(R column, Collection<?> value)
notIn(boolean condition, R column, Collection<?> value)
  • 字段 IN (value.get(0), value.get(1), ...)
  • 例: notIn("age",{1,2,3})--->`age not in (1,2,3)
notIn(R column, Object... values)
notIn(boolean condition, R column, Object... values)
  • 字段 NOT IN (v0, v1, ...)
  • 例: notIn("age", 1, 2, 3)--->age not in (1,2,3)

# inSql🔥

inSql(R column, String inValue)
inSql(boolean condition, R column, String inValue)
  • 字段 IN ( sql语句 )
  • 例: inSql("age", "1,2,3,4,5,6")--->age in (1,2,3,4,5,6)
  • 例: inSql("id", "select id from table where id < 3")--->id in (select id from table where id < 3)

# notInSql🔥

notInSql(R column, String inValue)
notInSql(boolean condition, R column, String inValue)
  • 字段 NOT IN ( sql语句 )
  • 例: notInSql("age", "1,2,3,4,5,6")--->age not in (1,2,3,4,5,6)
  • 例: notInSql("id", "select id from table where id < 3")--->age not in (select id from table where id < 3)

# exists🔥

exists(String existsSql)
exists(boolean condition, String existsSql)
  • 拼接 EXISTS ( sql语句 )
  • 例: exists("select id from table where age = 1")--->exists (select id from table where age = 1)

# notExists🔥

notExists(String notExistsSql)
notExists(boolean condition, String notExistsSql)
  • 拼接 NOT EXISTS ( sql语句 )
  • 例: notExists("select id from table where age = 1")--->not exists (select id from table where age = 1)

# groupBy🔥

groupBy(R... columns)
groupBy(boolean condition, R... columns)
  • 分组：GROUP BY 字段, ...
  • 例: groupBy("id", "name")--->group by id,name

# having🔥

having(String sqlHaving, Object... params)
having(boolean condition, String sqlHaving, Object... params)
  • HAVING ( sql语句 )
  • 例: having("sum(age) > 10")--->having sum(age) > 10
  • 例: having("sum(age) > {0}", 11)--->having sum(age) > 11

# orderByAsc🔥

orderByAsc(R... columns)
orderByAsc(boolean condition, R... columns)
  • 排序：ORDER BY 字段, ... ASC
  • 例: orderByAsc("id", "name")--->order by id ASC,name ASC

# orderByDesc🔥

orderByDesc(R... columns)
orderByDesc(boolean condition, R... columns)
  • 排序：ORDER BY 字段, ... DESC
  • 例: orderByDesc("id", "name")--->order by id DESC,name DESC

# orderBy

orderBy(boolean condition, boolean isAsc, R... columns)
  • 排序：ORDER BY 字段, ...
  • 例: orderBy(true, true, "id", "name")--->order by id ASC,name ASC

# or🔥

or()
or(boolean condition)
  • 拼接 OR

注意事项: 主动调用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)

  • 例: 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 嵌套
  • 例: or(i -> i.eq("name", "李白").ne("status", "活着"))--->or (name = '李白' and status <> '活着')

# and🔥

and(Consumer<Param> consumer)
and(boolean condition, Consumer<Param> consumer)
  • AND 嵌套
  • 例: and(i -> i.eq("name", "李白").ne("status", "活着"))--->and (name = '李白' and status <> '活着')

# nested🔥

nested(Consumer<Param> consumer)
nested(boolean condition, Consumer<Param> consumer)
  • 正常嵌套 不带 AND 或者 OR
  • 例: nested(i -> i.eq("name", "李白").ne("status", "活着"))--->(name = '李白' and status <> '活着')

# apply

apply(String applySql, Object... params)
apply(boolean condition, String applySql, Object... params)
  • 拼接 sql

注意事项: 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!

  • 例: apply("id = 1")--->id = 1
  • 例: apply("date_format(dateColumn,'%Y-%m-%d') = '2008-08-08'")--->date_format(dateColumn,'%Y-%m-%d') = '2008-08-08'")
  • 例: apply("date_format(dateColumn,'%Y-%m-%d') = {0}", "2008-08-08")--->date_format(dateColumn,'%Y-%m-%d') = '2008-08-08'")

# last

last(String lastSql)
last(boolean condition, String lastSql)
  • 无视优化规则直接拼接到 sql 的最后

注意事项: 只能调用一次,多次调用以最后一次为准 有sql注入的风险,请谨慎使用

  • 例: last("limit 1")

# QueryWrapper

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🔥

select(String... sqlSelect)
select(Predicate<TableFieldInfo> predicate)
select(Class<T> entityClass, Predicate<TableFieldInfo> predicate)
  • 设置查询字段

说明: 以上方分法为两类.

第二类方法为: 过滤查询字段(主键除外),入参不包含 class 的调用前需要wrapper内的entity属性有值! 这两类方法重复调用以最后一次为准

  • 例: select("id", "name", "age")
  • 例: select(i -> i.getProperty().startsWith("test"))

# UpdateWrapper

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

set(String column, Object val)
set(boolean condition, String column, Object val)
  • SQL SET 字段
  • 例: set("name", "老李头")
  • 例: set("name", "")--->数据库字段值变为空字符串
  • 例: set("name", null)--->数据库字段值变为null

# setSql

setSql(String sql)
  • 设置 SET 部分 SQL
  • 例: setSql("name = '老李头'")

# lambda

  • 获取 LambdaWrapper 在QueryWrapper中是获取LambdaQueryWrapper 在UpdateWrapper中是获取LambdaUpdateWrapper

# 使用 Wrapper 自定义SQL

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