mybatis-plus配置找不到Mapper接口路径的坑

谁借莪１个温暖的怀抱￠ 2021-12-20 07:59 1010阅读 0赞

mybatis-plus今天遇到一个问题，就是mybatis 没有读取到mapper.xml 文件。

特此记录一下，问题如下：

org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.husy.mapper.SystemUserMapper.findUserByName
    
    	at com.baomidou.mybatisplus.core.override.MybatisMapperMethod$SqlCommand.<init>(MybatisMapperMethod.java:242)
    	at com.baomidou.mybatisplus.core.override.MybatisMapperMethod.<init>(MybatisMapperMethod.java:54)
    	at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.lambda$cachedMapperMethod$0(MybatisMapperProxy.java:65)
    	at java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1660)
    	at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.cachedMapperMethod(MybatisMapperProxy.java:65)
    	at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.invoke(MybatisMapperProxy.java:60)
    	at com.sun.proxy.$Proxy72.findUserByName(Unknown Source)
    	at com.husy.service.impl.SystemUserServiceImpl.findUserByName(SystemUserServiceImpl.java:23)

**错误代码如下：**

mapper.xml 目录  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMyMzQ5Mjg_size_16_color_FFFFFF_t_70]  
代码如下：

单元测试

@Test
    public void findUser(){ 
    	SystemUser systemUser= systemUserService.findUserByName("admin");
    	System.out.println(systemUser.toString());
    }

mybatis-puls 配置

@EnableTransactionManagement
    @Configuration
    @MapperScan("com.husy.mapper")
    public class MybatisConfig { 
    
        /** * mybatis-plus 分页插件 */
        @Bean
        public PaginationInterceptor paginationInterceptor() { 
            return new PaginationInterceptor();
        }
    }

service实现

@Service
    public class SystemUserServiceImpl implements SystemUserService { 
    	@Autowired
    	private SystemUserMapper userMapper;
    
    	@Override
    	public SystemUser findUserByName(String name) { 
    		return userMapper.findUserByName(name);
    	}
    }

mapper 接口

@Component
    public interface SystemUserMapper { 
    	SystemUser findUserByName(@Param("userAccount") String name);
    }

mapper.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="com.husy.mapper.SystemUserMapper">
        <resultMap id="systemUserMap" type="com.husy.domain.SystemUser" >
            <id column="user_id" property="userId" />
            <result column="user_account" property="userAccount" />
            <result column="user_password" property="userPassword" />
            <result column="user_phone" property="userPhone" />
        </resultMap>
        <select id="findUserByName" resultMap="systemUserMap">
             SELECT
                user_id,
                user_account,
                user_password,
                user_phone
             FROM t_system_user
             where user_account = #{userAccount}
        </select>
    </mapper>

通过上面的代码可以看出。mapper接口中的方法和映射文件中的方法名称是一样的。不存在名称错误导致的情况，返回值，参数类型等你都正确。如果找不到方法，那一定是映射文件配置问题，只有没有读取到，才会出现找不到的情况。  
我的配置如下：

## 问题出错的关键位置 ##

我这里引用的是 mybatis-plus-boot-starte 依赖

<dependency>
        <groupId>com.baomidou</groupId>
         <artifactId>mybatis-plus-boot-starter</artifactId>
         <version>3.1.0</version>
     </dependency>

mapper.xml 的文件引用路径配置如下：

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

这就导致，mybatis 读取不到 mapper映射文件。

**经过查阅**：

*  **如果引用mybatis-plus-boot-starter 依赖，需要配置 mybatis-plus.mapper-locations**
 *  **如果引用mybatis-plus 依赖，需要配置 mybatis.mapper-locations**

如下：

## 引用 mybatis-plus 包 ##

<dependency>
       <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus</artifactId>
        <version>3.1.0</version>
    </dependency>

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

## 引用 mybatis-plus-boot-starter 包 ##

<dependency>
         <groupId>com.baomidou</groupId>
         <artifactId>mybatis-plus-boot-starter</artifactId>
         <version>3.1.0</version>
     </dependency>

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

只要选用其中一种方式，就没有问题了。

今天看到评论区有小伙伴说没有作用，这里给了一份Demo ，有问题的小伙伴可以比对一下。

## POM ##

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.2.2.RELEASE</version>
            <relativePath/> 
        </parent>
        <groupId>com.example</groupId>
        <artifactId>demo</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>demo</name>
        <description>Demo project for Spring Boot</description>
    
        <properties>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.1.1</version>
            </dependency>
    
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
            </dependency>
            <dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>mybatis-plus-boot-starter</artifactId>
                <version>3.3.0</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
                <exclusions>
                    <exclusion>
                        <groupId>org.junit.vintage</groupId>
                        <artifactId>junit-vintage-engine</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    
    </project>

## application.properties ##

# DataSource Config
    spring.datasource.url=jdbc:mysql://localhost:3306/db_husy?allowMultiQueries=true&useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=GMT%2B8&zeroDateTimeBehavior=CONVERT_TO_NULL
    spring.datasource.username=root
    spring.datasource.password=123456
    spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
    
    mybatis-plus.mapper-locations=classpath:/mapper/*.xml

## MybatisConfig ##

*/
    @EnableTransactionManagement
    @Configuration
    @MapperScan("com.example.demo.mapper")
    public class MybatisConfig { 
    	/**mybatis-plus 分页插件*/
    	@Bean
    	public PaginationInterceptor paginationInterceptor() { 
    		return new PaginationInterceptor();
    	}
    }

其他文件基本没变化。附上目录  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMyMzQ5Mjg_size_16_color_FFFFFF_t_70 1]

## 单元测试 ##

@SpringBootTest
    class DemoApplicationTests { 
    	@Autowired
    	SystemUserService systemUserService;
    	@Test
    	public void findUser(){ 
    		SystemUser systemUser= systemUserService.findUserByName("admin");
    		System.out.println(systemUser.toString());
    	}
    
    }

![在这里插入图片描述][20191220160935864.png]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMyMzQ5Mjg_size_16_color_FFFFFF_t_70]: /images/20211220/0ad57140d0744a40a5e5c2188a94ee52.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMyMzQ5Mjg_size_16_color_FFFFFF_t_70 1]: /images/20211220/4ee3b97e70e246b08b5a0b6d9cfb9521.png
[20191220160935864.png]: /images/20211220/bff114e2df4d444bbb44a315329cb316.png