SpringBoot demo（三）一整合mybatis

mybatis

引入依赖

<!-- mybatis   start -->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.2</version>
</dependency>
<!-- mybatis   end -->

<!-- mysql 数据库连接  start -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>
<!-- mysql 数据库连接  end -->

配置

spring:
  # 数据库配置
  datasource:
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
      username: xxxxxxxx
      password: xxxxxxxx

mybatis:
  # 配置mapper的扫描，找到所有的mapper.xml映射文件
  mapper-locations: classpath*:mapper/system/*Mapper.xml
  # 搜索指定包内的实体
  typeAliasesPackage: com.boo.domain

# 配置不同包下的日志打印级别
logging:
  level:
    com:
      boo:
        # 打印sql语句
        mapper: debug

一个简单的数据库查询例子 (查询用户列表）
创建一张表，随便添加几条数据

-- 创建表sql
CREATE TABLE `sys_user` (
  `id` varchar(32) NOT NULL,
  `user_name` varchar(30) NOT NULL,
  `password` varchar(100) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='系统用户表';

INSERT INTO `springboot`.`sys_user` (`id`, `user_name`, `password`) VALUES ('cs001', 'zhangsan', '123456789');
INSERT INTO `springboot`.`sys_user` (`id`, `user_name`, `password`) VALUES ('cs002', 'lisi', '123456789');
INSERT INTO `springboot`.`sys_user` (`id`, `user_name`, `password`) VALUES ('cs003', 'wangwu', '123456789');
INSERT INTO `springboot`.`sys_user` (`id`, `user_name`, `password`) VALUES ('cs004', 'zhaoliu', '123456789');

在这里插入图片描述
3.1 SysUser.java与上一致
3.2 SysLoginController.java新增一个查询用户列表的接口

```java
@RestController
@Slf4j
public class SysLoginController {
    @Autowired
    private ISysLoginService loginService;
    
    /* 功能描述: 查询用户列表
     * @param user
    * @return: java.util.List<com.boo.domain.system.SysUser>
    * @Author: boo
    * @Date: 2021/3/23 16:41
    */
    @RequiresPermissions("data:query")
    @GetMapping("/userList")
    public List<SysUser> userList(SysUser user) {
        return loginService.selectUserList(user);
    }

}
```

3.3 `SysLoginServiceImpl.java`新增一个查询用户列表的接口

```java
@Service
public class SysLoginServiceImpl implements ISysLoginService {
    @Autowired
    private SysUserMapper sysUserMapper;

    /** 查询用户列表 */
    @Override
    public List<SysUser> selectUserList(SysUser user) {
        return sysUserMapper.selectUserList(user);
    }
}
```

3.4 `SysUserMapper.java`

```java
package com.boo.mapper.system;

import com.boo.domain.system.SysUser;

import java.util.List;

/** 
 * description: SysUserMapper <br>
 * date: 2021/3/23 16:32 <br>
 * author: boo <br>
 * version: 1.0 <br>
 */
public interface SysUserMapper {
    List<SysUser> selectUserList(SysUser user);
}
```

3.5  `SysUserMapper.xml`

```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.boo.mapper.system.SysUserMapper">

	<resultMap type="com.boo.domain.system.SysUser" id="SysUserResult">
		<id     property="id" column="id" />
		<result property="userName" column="user_name" />
		<result property="password" column="password" />
	</resultMap>

	<select id="selectUserList" parameterType="com.boo.domain.system.SysUser" resultMap="SysUserResult">
		SELECT
			u.id,
			u.user_name,
			u.password
		FROM
			sys_user u
			<where>
				<if test="userName != null and userName != ''">
					AND r.user_name = #{userName}
				</if>
			</where>
	</select>
</mapper>
```

项目启动
报错：org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.boo.mapper.system.SysUserMapper' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
原因：mapper没有注册
解决方式1：在mapper接口上添加 @Mapper注解

解决方式2：配置全局的mapper扫描注册
在启动类上加@MapperScan(*要扫描的包*)注解

解决方式3：写一个专门的注解配置的配置类ApplicationConfig.java
方式同2，只不过把@MapperScan注解单独放在配置类中，保证SpringBootDemoApplication.java(启动类)的简介, 配置类内容如下：

package com.boo.framework.config;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Configuration;

/** 功能描述: 程序注解配置
 *      主要放一些注解配置
* @Author: boo
* @Date: 2021/3/24 8:53
*/
@Configuration
@MapperScan("com.boo.mapper") // 指定要扫描的Mapper类的包的路径
public class ApplicationConfig
{
    
    

}

SpringBoot demo（三） 一 整合mybatis

mybatis

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SpringBoot demo（三）一整合mybatis