SpringBoot 集成 MyBatis 几个注意的问题

偏执的太偏执、 2021-06-11 15:13 474阅读 0赞

1、项目是在eclipse上用maven构建的,采用Dao与xml映射的形式

<parent>
    	<groupId>org.springframework.boot</groupId>
    	<artifactId>spring-boot-starter-parent</artifactId>
    	<version>2.0.2.RELEASE</version>
    </parent>
    	
    <dependency>
    	<groupId>org.springframework.boot</groupId>
    	<artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    	
    <dependency>
    	<groupId>mysql</groupId>
    	<artifactId>mysql-connector-java</artifactId>
    </dependency>
    	
    <dependency>
    	<groupId>org.mybatis.spring.boot</groupId>
    	<artifactId>mybatis-spring-boot-starter</artifactId>
    	<version>1.3.1</version>
    </dependency>

2、项目结构

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYWh1YWxl_size_16_color_FFFFFF_t_70][]

3、添加 @MapperScan(\{"com.xhl.springboot\_1.dao"\})

配置Dao的接口所在包名(在启动类或配置类)

package com.xhl.springboot_1;
    
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    /**
     * Hello world!
     *
     */
    
    @SpringBootApplication
    @MapperScan({"com.xhl.springboot_1.dao"})
    public class Application 
    {
        public static void main( String[] args )
        {
        	SpringApplication.run(Application.class,args);
        }
    }

配置错误启动会报如下错误

***************************
    APPLICATION FAILED TO START
    ***************************
    
    Description:
    
    Field userMapper in com.xhl.springboot_1.service.impl.UserServiceImpl required a bean of type 'com.xhl.springboot_1.dao.UserMapper' that could not be found.
    
    
    Action:
    
    Consider defining a bean of type 'com.xhl.springboot_1.dao.UserMapper' in your configuration.

4、添加 mybatis.mapperLocations=classpath:\*\*/mapper/\*.xml

application.propertirs或(yml)中配置Dao的实体类所在位置

注意 propertirs文件和yml文件写法在格式上的区别

# --- {MyBatis} RDB JDBC Connection
    spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test
    spring.datasource.username=root
    spring.datasource.password=123456
    spring.datasource.driverClassName=com.mysql.jdbc.Driver
    mybatis.mapperLocations=classpath:**/mapper/*.xml

如果\*.xml与dao的接口类\*.java在同一个包下(即相同路径),这块不进行配置也可以正确运行，否则虽然项目会正常启动，但是在请求数据时，dao会找不到xml，错误信息如下

控制台 org.apache.ibatis.binding.BindingException 异常

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYWh1YWxl_size_16_color_FFFFFF_t_70 1][]

页面效果

![20190130112537218.PNG][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYWh1YWxl_size_16_color_FFFFFF_t_70]: /images/20210605/3134397314984187bb15afdf16b3117e.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYWh1YWxl_size_16_color_FFFFFF_t_70 1]: /images/20210605/535cdc8893f24f4ea4d63fbf808d5355.png
[20190130112537218.PNG]: /images/20210605/e0acaabefc25451a82e58c12fedc1572.png