springboot集成mybatis时提示有多个Mapper（dao）实例

2017-05-22 11:19:27 3.5k 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

Springboot整合mybatis继承mapper接口，扩展自己的dao接口 Springboot整合mybatis继承mapper接口，扩展自己的dao接口这里主要介绍Mybatis-Generator自动生成model、mapper后，如何在已有的基础上去扩展，写一些比较复杂的接口以及我自己遇到的坑。前景依靠自己在项目上的经验和网上查找的资料，自己搭建了springboot项目，集成mybatis后，通过测试，发现一切OK。但是mybatis自动生成的mapper... 阅读详情

我在使用springboot集成mybatis后，项目编译成功，但是在启动Application运行项目时，提示dao（mapper接口）有多个实例。
错误信息如下





Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.

2017-05-22 10:51:45.858 ERROR 2076 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 



***************************

APPLICATION FAILED TO START

***************************



Description:



file [E:\Workspaces\springboot-mybatis\target\classes\springboot\dao\CityDao.class] required a single bean, but 4 were found:

	- &cityDao: defined in file [E:\Workspaces\springboot-mybatis\target\classes\springboot\dao\CityDao.class]

	- systemEnvironment: a programmatically registered singleton	- contextParameters: a programmatically registered singleton	- contextAttributes: a programmatically registered singleton



Action:



Consider marking one of the beans as @Primary, updating the consumer to accept multiple beans, or using @Qualifier to identify the bean that should be consumed

springboot\dao\CityDao.class，这个CityDao是我定义的一个Mapepr接口，它被service层引用。
其他配置和代码如下：
1、application.properties



## jdbc source

spring.datasource.url=jdbc:mysql://localhost:3306/springbootdb?useUnicode=true&characterEncoding=utf8

spring.datasource.username=root

spring.datasource.password=root

spring.datasource.driver-class-name=com.mysql.jdbc.Driver



## Mybatis

mybatis.typeAliasesPackage=springboot.entity

mybatis.mapperLocations=classpath\:mapper/*.xml

2、CityDao.java



public interface CityDao {

	

	City get(int id);



}

3、cityMapper.xml



<?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="springboot.dao.CityDao" >

	<resultMap type="springboot.entity.City" id="BaseResultMap">

		<id column="id" property="id" />

		<result column="province_id" property="provinceId" />

		<result column="city_name" property="cityName" jdbcType="VARCHAR"/>

		<result column="description" property="description" jdbcType="VARCHAR"/>

	</resultMap>

	

	<sql id="Base_Column_List" >

		id,province_id,city_name,description

	</sql>

	<select id="get" parameterType="java.lang.Integer" resultMap="BaseResultMap">

		select

		<include refid="Base_Column_List"/>

		from city

		where id = #{id}

	</select>

</mapper>

4、CityServiceImpl.java





@Service

public class CityServiceImpl implements CityService{

	

	@Autowired

	private CityDao cityDao;

	

	public City get(String id){

		return cityDao.get(Integer.parseInt(id));

	}



}

5、App.java 负责启动springboot



package springboot;



import org.mybatis.spring.annotation.MapperScan;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;





@SpringBootApplication

@MapperScan("springboot.dao")

public class App 

{

    public static void main( String[] args )

    {

        SpringApplication.run(App.class, args);

    }

}