前言

上一篇发布的是springboot整合mybatis和mybatis的分页插件，这次就直接上手整合mybatis-Plus。

1. spring-boot-starter-web ，springmvc的依赖；

2. mybatis-spring-boot-starter ，springboot整合mybatis依赖；

3. mysql-connector-java ，springboot整合mysql依赖；

4. lombok ，springboot整合实体类的getsettostring等方法依赖；

5. spring-boot-starter-test ，单元测试依赖；

   org.springframework.boot spring-boot-starter-web

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.1.1</version>
        </dependency>
   

   如果将xml文件放入src包中需要再定义

    <resources>
         <resource>
             <directory>src/main/java</directory>
             <filtering>false</filtering>
             <includes>
                 <include>**/mapper/*.xml</include>
             </includes>
         </resource>
     </resources>
   

进行数据库的连接，和Mybatis-Plus的路径扫描控制台打印sql语句等等。

	    spring:
	      datasource:
	        url: jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8
	        username: root
	        password: root
	        driver-class-name: com.mysql.cj.jdbc.Driver
	    mybatis-plus:
	      configuration:
	        map-underscore-to-camel-case: true
	        log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
	    
	      mapper-locations: classpath:com/bdqn/mapper/*.xml

启动类进行扫描mapper接口

package com.xxx;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan("com.xxx.dao")
public class Demo01MybatisplusApplication {

    public static void main(String[] args) {
        SpringApplication.run(Demo01MybatisplusApplication.class, args);
    }

}

在Mapper接口中继承BaseBaseMapper类，这是Mybatis-Plus中的内置类，有很多操作数据库的方法

进行继承，即可使用方法。

package com.xxx.dao;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.xxx.entity.User;

public interface UserDao extends BaseMapper<User> {
}

最终在Service实现类中使用相应方法。

在配置文件中注册

	import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
	import org.springframework.context.annotation.Bean;
	import org.springframework.context.annotation.Configuration;
	import org.springframework.transaction.annotation.EnableTransactionManagement;
	
	@EnableTransactionManagement
	@Configuration
	public class MybatisPlusConfig {
	
	    /**
	     * 分页插件
	     */
	    @Bean
	    public PaginationInterceptor paginationInterceptor() {
	        return new PaginationInterceptor();
	    }
	}

在实现层进行操作，万变不离其宗，传入当前页数和当页条数

@Service
@Transactional
public class UserServiceImpl implements UserService {

    @Autowired
    private UserDao userDao;

    @Override
    public IPage getPageAllByUser() {
        Page page = new Page(1,2);
        return userDao.getPageAllByUser(page);
    }
}

增加条件搜索分页
Service层

@Service
@Transactional
public class UserServiceImpl implements UserService {

    @Autowired
    private UserDao userDao;

    @Override
    public IPage getPageAllByUser(User user) {
    //分页处理，显示第pageNum页的pageSize条数据
        Page page = new Page(1,2);
        return userDao.getPageAllByUser(page,user);
    }
}

Mapper层

public interface UserDao extends BaseMapper<User> {
    IPage getPageAllByUser(Page page,User user);
}

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.bdqn.dao.UserDao">
<select id="getPageAllByUser" resultType="com.bdqn.entity.User">
select * from t_user
    <if test="age!=null">
       where age = #{age,jdbcType=INTEGER}
    </if>
</select>
</mapper>

简单的自定义条件分页也就完成了。

springboot整合Mybatis-Plus也就完成了，我在这里也是参考了Mybatis-Plus的中文官网，官网中讲解的很清晰，也有很多的注解和内置方法，以上也是本人的自我理解，如有不当之处，请大家包含，下次我要整理的是一个概念: 读写分离。