本文源码：Gitee·点这里
这里主要用到QueryWrapper和UpdateWrapper两个类，用于生成sql的where条件。
UpdateWrapper
根据 whereEntity 条件，删除记录
删除年龄为10岁的用户
@Test
public void testDelete() {
int result = userMapper.delete(new UpdateWrapper().eq("age", 10));
System.out.println(result);
}
执行日志：
JDBC Connection [HikariProxyConnection@161938368 wrapping com.mysql.cj.jdbc.ConnectionImpl@c1fa7d4] will not be managed by Spring
==> Preparing: DELETE FROM user WHERE (age = ?)
==> Parameters: 10(Integer)
<== Updates: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@7b7b3edb]
1
更新 whereEntity 条件，更新记录
修改小于20岁用户的邮箱
@Test
public void testUpdate() {
User user = new User();
user.setEmail("[email protected]");
int result = userMapper.update(user, new UpdateWrapper().le("age", 20));
System.out.println(result);
}
执行结果：
JDBC Connection [HikariProxyConnection@203401172 wrapping com.mysql.cj.jdbc.ConnectionImpl@7a93b263] will not be managed by Spring
==> Preparing: UPDATE user SET email=? WHERE (age <= ?)
==> Parameters: [email protected](String), 20(Integer)
<== Updates: 3
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1dbb650b]
3
QueryWrapper
根据 whereEntity 条件，查询一条记录
查询id为2的用户
@Test
public void testSelectOne() {
User user = userMapper.selectOne(new QueryWrapper().eq("id", 2L));
System.out.println(user);
}
执行日志：
JDBC Connection [HikariProxyConnection@1689723487 wrapping com.mysql.cj.jdbc.ConnectionImpl@33db72bd] will not be managed by Spring
==> Preparing: SELECT id,name,age,email FROM user WHERE (id = ?)
==> Parameters: 2(Long)
<== Columns: id, name, age, email
<== Row: 2, Jack, 20, [email protected]
<== Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@15cea7b0]
User{id=2, name='Jack', age=20, email='[email protected]'}
根据 whereEntity 条件，查询记录数量
查询年龄在20-30之前用户数量
@Test
public void testSelectCount() {
Integer count = userMapper.selectCount(new QueryWrapper().between("age", 20, 30));
System.out.println(count);
}
执行日志：
JDBC Connection [HikariProxyConnection@859193874 wrapping com.mysql.cj.jdbc.ConnectionImpl@2216effc] will not be managed by Spring
==> Preparing: SELECT COUNT( 1 ) FROM user WHERE (age BETWEEN ? AND ?)
==> Parameters: 20(Integer), 30(Integer)
<== Columns: COUNT( 1 )
<== Row: 3
<== Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6b474074]
3
更多条件构造器（来自官网）
#allEq
allEq(Map params)
allEq(Map params, boolean null2IsNull)
allEq(boolean condition, Map params, boolean null2IsNull)
- 全部eq(或个别isNull)
个别参数说明:
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
- 例1:
allEq({id:1,name:"老王",age:null})--->id = 1 and name = '老王' and age is null - 例2:
allEq({id:1,name:"老王",age:null}, false)--->id = 1 and name = '老王'
allEq(BiPredicate filter, Map params)
allEq(BiPredicate filter, Map params, boolean null2IsNull)
allEq(boolean condition, BiPredicate filter, Map params, boolean null2IsNull)
个别参数说明:
filter : 过滤函数,是否允许字段传入比对条件中
params 与 null2IsNull : 同上
- 例1:
allEq((k,v) -> k.indexOf("a") >= 0, {id:1,name:"老王",age:null})--->name = '老王' and age is null - 例2:
allEq((k,v) -> k.indexOf("a") >= 0, {id:1,name:"老王",age:null}, false)--->name = '老王'
#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 NOT 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")--->id not in (select id from table where id < 3)
#groupBy
groupBy(R... columns)
groupBy(boolean condition, R... columns)
- 分组：GROUP BY 字段, ...
- 例:
groupBy("id", "name")--->group by id,name
#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
排序：ORDER BY 字段, ...
- 例:
orderBy(true, true, "id", "name")--->order by id ASC,name ASC
#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
#func
func(Consumer consumer)
func(boolean condition, Consumer consumer)
- func 方法(主要方便在出现if...else下调用不同方法能不断链)
- 例:
func(i -> if(true) {i.eq("id", 1)} else {i.ne("id", 1)})
#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 consumer)
or(boolean condition, Consumer 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 consumer)
and(boolean condition, Consumer 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 consumer)
nested(boolean condition, Consumer 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
pply(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")
#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)