SpringBoot整合MybatisPlus3.X之Wrapper(五)

官方文档说明:

• 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

• 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

• 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)

• 以下方法入参中的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!!!

• 以下举例均为使用普通wrapper,入参为Map和List的均以json形式表现!

• 使用中如果入参的Map或者List为空,则不会加入最后生成的sql中!!!

警告:

不支持以及不赞成在 RPC 调用中把 Wrapper 进行传输

1. wrapper 很重

2. 传输 wrapper 可以类比为你的 controller 用 map 接收值(开发一时爽,维护火葬场)

3. 正确的 RPC 调用姿势是写一个 DTO 进行传输,被调用方再根据 DTO 执行相应的操作

4. 我们拒绝接受任何关于 RPC 传输 Wrapper 报错相关的 issue 甚至 pr

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

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

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 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)

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

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

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

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(Function<Param, Param> func)
or(boolean condition, Function<Param, Param> func)

• 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(Function<Param, Param> func)
and(boolean condition, Function<Param, Param> func)

• 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(Function<Param, Param> func)
nested(boolean condition, Function<Param, Param> func)

• 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")

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)

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"))

excludeColumns

@Deprecated

• 排除查询字段

已从3.0.5版本上移除此方法!

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

需求来源:

在使用了mybatis-plus之后, 自定义SQL的同时也想使用Wrapper的便利应该怎么办？ 在mybatis-plus版本3.0.7得到了完美解决 版本需要大于或等于3.0.7, 以下两种方案取其一即可

Service.java

mysqlMapper.getAll(Wrappers.<MysqlData>lambdaQuery().eq(MysqlData::getGroup, 1));

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>

代码演示

• pom.xml

  <dependencies>
          <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-starter</artifactId>
          </dependency>
          <dependency>
              <groupId>com.baomidou</groupId>
              <artifactId>mybatis-plus-boot-starter</artifactId>
              <version>3.2.0</version>
          </dependency>
          <dependency>
              <groupId>org.projectlombok</groupId>
              <artifactId>lombok</artifactId>
          </dependency>
          <dependency>
              <groupId>com.h2database</groupId>
              <artifactId>h2</artifactId>
              <scope>runtime</scope>
          </dependency>
  ​
          <!-- for testing -->
          <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-starter-test</artifactId>
              <scope>test</scope>
          </dependency>
      </dependencies>

• application.yml

  # DataSource Config
  spring:
    datasource:
      driver-class-name: org.h2.Driver
      url: jdbc:h2:tcp://192.168.180.115:19200/~/mem/test
      username: root
      password: test
  ​
  # Logger Config
  logging:
    level:
      com.mp.wrapper: debug
  ​

• 实体类

  @Data
  public class Role {
      private Long id;
      private String roleName;
      private String roleDescribe;
  }
  ​
  @Data
  public class User {
      private Long id;
      private String name;
      private Integer age;
      private String email;
      private Long roleId;
  }

• Mapper

  public interface RoleMapper extends BaseMapper<Role> {
  }
  public interface UserMapper extends BaseMapper<User> {
  }

• 启动类

  @SpringBootApplication
  @MapperScan("com.mp.wrapper.mapper")
  public class WrapperApplication {
  ​
      public static void main(String[] args) {
          SpringApplication.run(WrapperApplication.class, args);
      }
  ​
  }

  ​

• 数据库脚本

  DROP TABLE IF EXISTS user;
  DROP TABLE IF EXISTS role;
  ​
  CREATE TABLE user
  (
    id      BIGINT (20) NOT NULL COMMENT '主键ID',
    name    VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名',
    age     INT (11) NULL DEFAULT NULL COMMENT '年龄',
    email   VARCHAR(50) NULL DEFAULT NULL COMMENT '邮箱',
    role_id BIGINT (20) NOT NULL COMMENT '角色ID',
    PRIMARY KEY (id)
  );
  ​
  CREATE TABLE role
  (
    id            BIGINT (20) NOT NULL COMMENT '主键ID',
    role_name     VARCHAR(30) NULL DEFAULT NULL COMMENT '角色名',
    role_describe VARCHAR(30) NULL DEFAULT NULL COMMENT '角色描述',
    PRIMARY KEY (id)
  );
  ​
  DELETE FROM user;
  DELETE FROM role;
  ​
  INSERT INTO role (id, role_name, role_describe)
  VALUES (1, '管理员', 'boos 级别'),
         (2, '用户', '就是个普通人'),
         (3, '程序猿', '偶尔需要用来祭天');
  ​
  INSERT INTO user (id, name, age, email, role_id)
  VALUES (1, 'Jone', 18, 'test1@baomidou.com', 1),
         (2, 'Jack', 20, 'test2@baomidou.com', 2),
         (3, 'Tom', 28, 'test3@baomidou.com', 2),
         (4, 'Sandy', 21, 'test4@baomidou.com', 3),
         (5, 'Billie', 24, 'test5@baomidou.com', 3);

  ​

• 测试类

  @SpringBootTest
  @RunWith(SpringRunner.class)
  class WrapperApplicationTests {
  ​
      @Resource
      private UserMapper userMapper;
      @Resource
      private RoleMapper roleMapper;
  ​
      @Test
      public void tests() {
          System.out.println("----- 普通查询 ------");
          //SELECT id,role_id,name,email,age FROM user WHERE (role_id = ?)
          List<User> plainUsers = userMapper.selectList(new QueryWrapper<User>().eq("role_id", 2L));
          List<User> lambdaUsers = userMapper.selectList(new QueryWrapper<User>().lambda().eq(User::getRoleId, 2L));
          Assert.assertEquals(plainUsers.size(), lambdaUsers.size());
          print(plainUsers);
  ​
          System.out.println("----- 带子查询(sql注入) ------");
          //SELECT id,role_id,name,email,age FROM user WHERE (role_id IN (select id from role where id = 2))
          List<User> plainUsers2 = userMapper.selectList(new QueryWrapper<User>().eq("1","1")
                  .inSql("role_id", "select id from role where id = 2"));
          List<User> lambdaUsers2 = userMapper.selectList(new QueryWrapper<User>().lambda()
                  .inSql(User::getRoleId, "select id from role where id = 2"));
          Assert.assertEquals(plainUsers2.size(), lambdaUsers2.size());
          print(plainUsers2);
  ​
          System.out.println("----- 带嵌套查询 ------");
          //SELECT id,role_id,name,email,age FROM user WHERE ( (role_id = ? OR role_id = ?) ) AND ( (age >= ?) )
          List<User> plainUsers3 = userMapper.selectList(new QueryWrapper<User>()
                  .nested(i -> i.eq("role_id", 2L).or().eq("role_id", 3L))
                  .and(i -> i.ge("age", 20)));
          List<User> lambdaUsers3 = userMapper.selectList(new QueryWrapper<User>().lambda()
                  .nested(i -> i.eq(User::getRoleId, 2L).or().eq(User::getRoleId, 3L))
                  .and(i -> i.ge(User::getAge, 20)));
          Assert.assertEquals(plainUsers3.size(), lambdaUsers3.size());
          print(plainUsers3);
  ​
          System.out.println("----- 自定义(sql注入) ------");
          // SELECT id,role_id,name,email,age FROM user WHERE (role_id = 2)
          List<User> plainUsers4 = userMapper.selectList(new QueryWrapper<User>()
                  .apply("role_id = 2"));
          print(plainUsers4);
  ​
          //UPDATE user SET email=? WHERE (id = ?)
          UpdateWrapper<User> uw = new UpdateWrapper<>();
          uw.set("email", null);
          uw.eq("id", 4);
          userMapper.update(new User(), uw);
          User u4 = userMapper.selectById(4);
          Assert.assertNull(u4.getEmail());
  ​
  ​
      }
  ​
      @Test
      public void lambdaQueryWrapper() {
          System.out.println("----- 普通查询 ------");
          List<User> plainUsers = userMapper.selectList(new LambdaQueryWrapper<User>().eq(User::getRoleId, 2L));
          List<User> lambdaUsers = userMapper.selectList(new QueryWrapper<User>().lambda().eq(User::getRoleId, 2L));
          Assert.assertEquals(plainUsers.size(), lambdaUsers.size());
          print(plainUsers);
  ​
          System.out.println("----- 带子查询(sql注入) ------");
          List<User> plainUsers2 = userMapper.selectList(new LambdaQueryWrapper<User>()
                  .inSql(User::getRoleId, "select id from role where id = 2"));
          List<User> lambdaUsers2 = userMapper.selectList(new QueryWrapper<User>().lambda()
                  .inSql(User::getRoleId, "select id from role where id = 2"));
          Assert.assertEquals(plainUsers2.size(), lambdaUsers2.size());
          print(plainUsers2);
  ​
          System.out.println("----- 带嵌套查询 ------");
          List<User> plainUsers3 = userMapper.selectList(new LambdaQueryWrapper<User>()
                  .nested(i -> i.eq(User::getRoleId, 2L).or().eq(User::getRoleId, 3L))
                  .and(i -> i.ge(User::getAge, 20)));
          List<User> lambdaUsers3 = userMapper.selectList(new QueryWrapper<User>().lambda()
                  .nested(i -> i.eq(User::getRoleId, 2L).or().eq(User::getRoleId, 3L))
                  .and(i -> i.ge(User::getAge, 20)));
          Assert.assertEquals(plainUsers3.size(), lambdaUsers3.size());
          print(plainUsers3);
  ​
          System.out.println("----- 自定义(sql注入) ------");
          List<User> plainUsers4 = userMapper.selectList(new QueryWrapper<User>()
                  .apply("role_id = 2"));
          print(plainUsers4);
  ​
          UpdateWrapper<User> uw = new UpdateWrapper<>();
          uw.set("email", null);
          uw.eq("id", 4);
          userMapper.update(new User(), uw);
          User u4 = userMapper.selectById(4);
          Assert.assertNull(u4.getEmail());
      }
  ​
      private <T> void print(List<T> list) {
          if (!CollectionUtils.isEmpty(list)) {
              list.forEach(System.out::println);
          }
      }
  ​
      /**
       * SELECT id,name,age,email,role_id FROM user
       * WHERE ( 1 = 1 ) AND ( ( name = ? AND age = ? ) OR ( name = ? AND age = ? ) )
       */
      @Test
      public void testSql() {
          QueryWrapper<User> w = new QueryWrapper<>();
          w.and(i -> i.eq("1", 1))
                  .nested(i ->
                          i.and(j -> j.eq("name", "a").eq("age", 2))
                                  .or(j -> j.eq("name", "b").eq("age", 2)));
          userMapper.selectList(w);
      }
  }