1. 官方网址

2. 基本应用

2.1 Mybatis + MP

2.1.1 导入依赖

<dependencies>
    <!-- mybatis-plus插件依赖 -->
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus</artifactId>
        <version>3.1.1</version>
    </dependency>
    <!--Mysql-->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.47</version>
    </dependency>
    <!--连接池-->
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.0.11</version>
    </dependency>
    <!--简化bean代码的⼯具包-->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.4</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.6.4</version>
    </dependency>
</dependencies>

2.1.2 先配置纯Mybatis应用

jdbc.properties：

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/atm?characterEncoding=utf-8
jdbc.username=root
jdbc.password=root

编写Mybatis主配置文件mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<properties resource="jdbc.properties"></properties>
<!--environments: 运⾏环境-->
<environments default="development">
 <environment id="development">
   <!--当前的事务事务管理器是JDBC-->
   <transactionManager type="JDBC"></transactionManager>
   <!--数据源信息 POOLED：使⽤mybatis的连接池-->
   <dataSource type="POOLED">
     <property name="driver" value="${jdbc.driver}"/>
     <property name="url" value="${jdbc.url}"/>
     <property name="username" value="${jdbc.username}"/>
     <property name="password" value="${jdbc.password}"/>
   </dataSource>
 </environment>
</environments>
<!--引⼊映射配置⽂件-->
<mappers>
 <mapper package="mapper"></mapper>
</mappers>
</configuration>

编写实体类User

@Data // getter setter @toString
@NoArgsConstructor // 无参构造
@AllArgsConstructor // 全参构造
public class User {
private Long id;
private String name;
private Integer age;
private String email;
}

编写UserMapper接⼝

public interface UserMapper {
 List<User> findAll();
}

编写UserMapper.xml⽂件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.lagou.mapper.UserMapper">
 <!-- 查询所有 -->
 <select id="findAll" resultType="com.lagou.pojo.User">
     select * from user
 </select>
</mapper>

测试

public class MPTest {
@Test
public void test1() throws IOException {
 InputStream resourceAsStream =
   Resources.getResourceAsStream("mybatis-config.xml");
 SqlSessionFactory sqlSessionFactory = new
   SqlSessionFactoryBuilder().build(resourceAsStream);
 SqlSession sqlSession = sqlSessionFactory.openSession();
 UserMapper mapper = sqlSession.getMapper(UserMapper.class);
 List<User> all = mapper.findAll();
 for (User user : all) {
   System.out.println(user);
 }
}
}

2.1.3 然后配置无侵入使用MP（Mybatis + MP应用）

第⼀步，将UserMapper继承BaseMapper，将拥有了BaseMapper中的所有⽅法：

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.lagou.pojo.User;
public interface UserMapper extends BaseMapper<User> {
 List<User> findAll();
}

第⼆步，使⽤MP中的MybatisSqlSessionFactoryBuilder进程构建：

@Test
public void test2() throws IOException {
 InputStream resourceAsStream =
     Resources.getResourceAsStream("mybatis-config.xml");
 // 这⾥使⽤的是MP中的MybatisSqlSessionFactoryBuilder
 SqlSessionFactory sqlSessionFactory = new
     MybatisSqlSessionFactoryBuilder().build(resourceAsStream);
 SqlSession sqlSession = sqlSessionFactory.openSession();
 UserMapper mapper = sqlSession.getMapper(UserMapper.class);
 // 可以调⽤BaseMapper中定义的⽅法
 List<User> all = mapper.selectList(null);
 for (User user : all) {
     System.out.println(user);
 }
 // 也可以使用原生的Mybatis手写方法
 List<User> all2 = mapper.findAll();
 for (User user : all2) {
     System.out.println(user);
 }
}

2.2 Spring + Mybatis + MP

引入依赖 ```xml
5.1.6.RELEASE

com.baomidou mybatis-plus 3.1.1 mysql mysql-connector-java 5.1.47 com.alibaba druid 1.0.11 org.projectlombok lombok 1.18.4 junit junit 4.12 org.slf4j slf4j-log4j12 1.6.4 org.springframework spring-webmvc ${spring.version} org.springframework spring-jdbc ${spring.version} org.springframework spring-test ${spring.version}


2. 编写jdbc.properties
```properties
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/mp?serverTimezone=GMT%2B8&useSSL=false
jdbc.username=root
jdbc.password=root

编写Spring主配置文件applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
                        http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans.xsd
                        http://www.springframework.org/schema/context
                        http://www.springframework.org/schema/context/spring-           context.xsd">
 <!--引⼊properties-->
<context:property-placeholder location="classpath:jdbc.properties"/>
<!--dataSource-->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
 <property name="driverClassName" value="${jdbc.driver}"/>
 <property name="url" value="${jdbc.url}"/>
 <property name="username" value="${jdbc.username}"/>
 <property name="password" value="${jdbc.password}"/>
</bean>
<!--这⾥使⽤MP提供的sqlSessionFactory,完成spring与mp的整合-->
<bean id="sqlSessionFactory"
     class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean"
     >
 <property name="dataSource" ref="dataSource"/>
</bean>
<!--扫描mapper接⼝，使⽤的依然是mybatis原⽣的扫描器-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
 <property name="basePackage" value="com.atm.mapper"/>
</bean>
</beans>

编写User对象以及UserMapper接⼝： ```java @Data @NoArgsConstructor @AllArgsConstructor public class User { private Long id; private String name; private Integer age; private String email; }

public interface UserMapper extends BaseMapper { List findAll(); }


5. 编写测试⽤例：
```java
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:applicationContext.xml")
public class TestSpringMP {
    @Autowired
    private UserMapper userMapper;
    @Test
    public void test2() throws IOException {
        List<User> users = this.userMapper.selectList(null);
        for (User user : users) {
            System.out.println(user);
        }
    }
}

2.3 SpringBoot + MP

导入依赖

<dependencies>
 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter</artifactId>
     <exclusions>
         <exclusion>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-logging</artifactId>
         </exclusion>
     </exclusions>
 </dependency>
 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-test</artifactId>
     <scope>test</scope>
 </dependency>
 <!--简化代码的⼯具包-->
 <dependency>
     <groupId>org.projectlombok</groupId>
     <artifactId>lombok</artifactId>
     <optional>true</optional>
 </dependency>
 <!--mybatis-plus的springboot⽀持-->
 <dependency>
     <groupId>com.baomidou</groupId>
     <artifactId>mybatis-plus-boot-starter</artifactId>
     <version>3.1.1</version>
 </dependency>
 <!--mysql驱动-->
 <dependency>
     <groupId>mysql</groupId>
     <artifactId>mysql-connector-java</artifactId>
     <version>5.1.47</version>
 </dependency>
 <dependency>
     <groupId>org.slf4j</groupId>
     <artifactId>slf4j-log4j12</artifactId>
 </dependency>
</dependencies>
<build>
 <plugins>
     <plugin>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-maven-plugin</artifactId>
     </plugin>
 </plugins>
</build>

编写application.properties

spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/mp?
useUnicode=true&characterEncoding=utf8&autoReconnect=true&allowMultiQueries=tr
ue&useSSL=false
spring.datasource.username=root
spring.datasource.password=root

编写pojo

@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
private Long id;
private String name;
private Integer age;
private String email;
}

编写mapper

public interface UserMapper extends BaseMapper<User> {
}

编写启动类

package com.atm.mp;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.WebApplicationType;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
@MapperScan("com.atm.mp.mapper") //设置mapper接⼝的扫描包
@SpringBootApplication
public class MyApplication {
 public static void main(String[] args) {
     SpringApplication.run(MyApplication.class, args);
 }
}

编写测试⽤例

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserMapperTest {
 @Autowired
 private UserMapper userMapper;
 @Test
 public void testSelect() {
     List<User> userList = userMapper.selectList(null);
     for (User user : userList) {
         System.out.println(user);
     }
 }
}

3. 通用CRUD

3.1 新增

3.2 修改

3.3 删除

3.4 查询

普通查询
分页查询
1. 方法定义： ```java /**

根据 entity 条件，查询全部记录（并翻⻚） *
@param page 分⻚查询条件（可以为 RowBounds.DEFAULT）

@param queryWrapper 实体对象封装操作类（可以为 null） */ IPage selectPage(IPage page, @Param(Constants.WRAPPER) Wrapper queryWrapper);


 2. 配置分⻚插件：
```java
package com.atm.mp;
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
@MapperScan("com.atm.mapper") //设置mapper接⼝的扫描包
public class MybatisPlusConfig {
  /**
  * 分⻚插件
  */
  @Bean
  public PaginationInterceptor paginationInterceptor() {
      return new PaginationInterceptor();
  }
}

测试⽤例：

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserMapperTest {
@Autowired
private UserMapper userMapper;
@Test
public void testSelectPage() {
  QueryWrapper<User> wrapper = new QueryWrapper<User>();
  wrapper.gt("age", 20); //年龄⼤于20岁
  Page<User> page = new Page<>(1,1);
  //根据条件查询数据
  IPage<User> iPage = this.userMapper.selectPage(page, wrapper);
  System.out.println("数据总条数：" + iPage.getTotal());
  System.out.println("总⻚数：" + iPage.getPages());
  List<User> users = iPage.getRecords();
  for (User user : users) {
      System.out.println("user = " + user);
  }
}
}

4. 配置

4.1 基本配置

4.1.1 配置文件configuration

MyBatis 配置⽂件位置，如果有单独的 MyBatis 配置，请将其路径配置到 configLocation 中。
springboot：

mybatis-plus.config-location = classpath:mybatis-config.xml

spring mvc：

<bean id="sqlSessionFactory"
class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean"
>
<property name="configLocation" value="classpath:mybatis-config.xml"/>
</bean>

4.1.2 mapper路径mapperLocations

MyBatis Mapper 所对应的 XML ⽂件位置，如果您在 Mapper 中有⾃定义⽅法（XML 中有⾃定义实
现），需要进⾏该配置，告诉 Mapper 所对应的 XML ⽂件位置。
springboot：

mybatis-plus.mapper-locations = classpath*:mybatis/*.xml

spring mvc：

<bean id="sqlSessionFactory"
class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean"
>
<property name="mapperLocations" value="classpath*:mybatis/*.xml"/>
</bean>

4.1.3 类别名typeAliasesPackage

MyBaits 别名包扫描路径，通过该属性可以给包中的类注册别名，注册后在 Mapper 对应的 XML ⽂件
中可以直接使⽤类名，⽽不⽤使⽤全限定的类名（即 XML 中调⽤的时候不⽤包含包名）。
springboot：

mybatis-plus.type-aliases-package = com.atm.mp.pojo

spring mvc：

<bean id="sqlSessionFactory"
class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean"
>
<property name="typeAliasesPackage"
value="com.baomidou.mybatisplus.samples.quickstart.entity"/>
</bean>

4.2 进阶配置

4.2.1 驼峰转换mapUnderscoreToCamelCase

类型：boolean
默认值：true

是否开启⾃动驼峰命名规则（camel case）映射，即从经典数据库列名 A_COLUMN（下划线命名）到
经典 Java 属性名 aColumn（驼峰命名）的类似映射。

#关闭⾃动驼峰映射，该参数不能和mybatis-plus.config-location同时存在
mybatis-plus.configuration.map-underscore-to-camel-case=false

4.2.2 cacheEnabled

类型：boolean
默认值：true

全局地开启或关闭配置⽂件中的所有映射器已经配置的任何缓存，默认为 true。

mybatis-plus.configuration.cache-enabled=false

4.3 DB配置

4.3.1 idType

类型：com.baomidou.mybatisplus.annotation.IdType
默认值：ID_WORKER

全局默认主键类型，设置后，即可省略实体对象中的@TableId(type = IdType.AUTO)配置。
springboot：

mybatis-plus.global-config.db-config.id-type=auto

springmvc：

<!--这⾥使⽤MP提供的sqlSessionFactory，完成了Spring与MP的整合-->
<bean id="sqlSessionFactory"
class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean"
>
  <property name="dataSource" ref="dataSource"/>
  <property name="globalConfig">
    <bean class="com.baomidou.mybatisplus.core.config.GlobalConfig">
      <property name="dbConfig">
        <bean
        class="com.baomidou.mybatisplus.core.config.GlobalConfig$DbConfig">
          <property name="idType" value="AUTO"/>
        </bean>
      </property>
    </bean>
  </property>
</bean>

4.3.2 tablePrefix

类型：string
默认值： null

表名前缀，全局配置后可省略@TableName()配置。
springboot：

mybatis-plus.global-config.db-config.table-prefix=tb_

spring mvc：

<bean id="sqlSessionFactory"
class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean"
>
  <property name="dataSource" ref="dataSource"/>
  <property name="globalConfig">
    <bean class="com.baomidou.mybatisplus.core.config.GlobalConfig">
      <property name="dbConfig">
        <bean
        class="com.baomidou.mybatisplus.core.config.GlobalConfig$DbConfig">
          <property name="idType" value="AUTO"/>
          <property name="tablePrefix" value="tb_"/>
        </bean>
      </property>
    </bean>
  </property>
</bean>

5. 条件构造器

等式

eq：等于
ne：不等于
gt：大于
ge：大于等于
lt：小于
le：小于等于
between 值1 and 值2
not between 值1 and 值2
in：字段 in（value1，value2）
notIn：字段 not in（value1，value2）

模式查询

like：LIKE ‘%值%’
notLike：NOT LIKE ‘%值%’
likeLeft：LIKE ‘%值’
likeRight：LIKE ‘值%’

排序

orderBy
orderByAsc
orderByDesc

逻辑查询

or
- 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)
and
- AND 嵌套
  6. 插件

Java 框架

11.Mybatis-Plus

1. 官方网址

2. 基本应用

2.1 Mybatis + MP

2.1.1 导入依赖

2.1.2 先配置纯Mybatis应用

2.1.3 然后配置无侵入使用MP（Mybatis + MP应用）

2.2 Spring + Mybatis + MP

2.3 SpringBoot + MP

3. 通用CRUD

3.1 新增

3.2 修改

3.3 删除

3.4 查询

4. 配置

4.1 基本配置

4.1.1 配置文件configuration

4.1.2 mapper路径mapperLocations

4.1.3 类别名typeAliasesPackage

4.2 进阶配置

4.2.1 驼峰转换mapUnderscoreToCamelCase

4.2.2 cacheEnabled

4.3 DB配置

4.3.1 idType

4.3.2 tablePrefix

5. 条件构造器

6. 插件