引入依赖
1 mp增删改查
1.1 增
@Test
public void testInsert() {
User user =
User.builder()
.userName(“itheima”)
.name(“itcast”)
.age(15)
.email(“itcast@itcast.cn”)
.password(“111111”)
.build();
int insert = userMapper.insert(user);
System.out.println(insert);
}
1.2
id删除
int count = userMapper.deleteById(8L);
id集合删除
List ids = new ArrayList();
ids.add(6);
ids.add(7);
userMapper.deleteBatchIds(ids);
map条件删除
Map
//delete from tb_user where user_name = ? and age = ?
map.put(“user_name”,”itcast”);
map.put(“age”,”18”);
userMapper.deleteByMap(map);
1.3
mp分页查询
@Test
public void testSelectPage() {
int current = 1;//当前页码
int size = 2;//每页显示条数
IPage
userMapper.selectPage(page,null);
List
long pages = page.getPages();//总页数 2
long total = page.getTotal();//总记录数 4
System.out.println(records);
System.out.println(pages);
System.out.println(total);
}
1.4 qw查询
常用api
eq( ) : 等于 =
ne( ) : 不等于 <>
gt( ) : 大于 >
ge( ) : 大于等于 >=
lt( ) : 小于 <
le( ) : 小于等于 <=
between ( ) : BETWEEN 值1 AND 值2
notBetween ( ) : NOT BETWEEN 值1 AND 值2
in( ) : in
notIn( ) :not in
1.5 模糊查询方法
like(“表列名”,”条件值”); 作用:查询包含关键字的信息,底层会自动添加匹配关键字,比如:%条件值%
likeLeft(“表列名”,”条件值”); 作用:左侧模糊搜索,也就是查询以指定条件值结尾的数据,比如:%条件值
likeRight(“表列名”,”条件值”);作用:右侧模糊搜索,也就是查询以指定条件值开头的数据,比如:条件值%
1.6 排序查询
orderByAsc 升序排序
orderByDesc 降序排序
1.7 lambdaqw
删除
@Test
public void testWrapper5() throws Exception{
LambdaQueryWrapper
int i = userMapper.delete(wrapper);
System.out.println(i);
}