SpringBoot（五）：SpringBoot整合MyBatis

曾经终败给现在 2022-05-16 00:50 200阅读 0赞

来源：[https://blog.csdn.net/saytime/article/details/74783296][https_blog.csdn.net_saytime_article_details_74783296]

上篇写了JdbcTemplate，但是现在使用Mybatis的人不少，所以这篇写一下SpringBoot整合Mybatis。

**一、数据准备**

其实还是上篇的，以防有人是直接看这篇的，就还是贴出来吧。

CREATE TABLE \`tb\_user\` (  
\`id\` int(11) NOT NULL AUTO\_INCREMENT COMMENT 'ID',  
\`username\` varchar(50) NOT NULL COMMENT '用户名',  
\`age\` int(11) NOT NULL COMMENT '年龄',  
\`ctm\` datetime NOT NULL COMMENT '创建时间',  
PRIMARY KEY (\`id\`)  
) ENGINE=InnoDB DEFAULT CHARSET=utf8

INSERT INTO \`db\_test\`.\`tb\_user\` (\`username\`, \`age\`, \`ctm\`) VALUES('张三', '18', NOW()) ;  
INSERT INTO \`db\_test\`.\`tb\_user\` (\`username\`, \`age\`, \`ctm\`) VALUES('李四', '20', NOW()) ;  
INSERT INTO \`db\_test\`.\`tb\_user\` (\`username\`, \`age\`, \`ctm\`) VALUES('王五', '19', NOW()) ;

二、引入依赖

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">

<artifactId>springbootdemo</artifactId>

<version>0.0.1-SNAPSHOT</version>

<name>springbootdemo</name>

<description>Demo project for Spring Boot</description>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-parent</artifactId>

<version>2.0.4.RELEASE</version>

</parent>

<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>

<java.version>1.8</java.version>

</properties>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId>

</dependency>

<groupId>mysql</groupId>

<artifactId>mysql-connector-java</artifactId>

<scope>runtime</scope>

</dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-test</artifactId>

</dependency>

<groupId>org.mybatis.spring.boot</groupId>

<artifactId>mybatis-spring-boot-starter</artifactId>

</dependency>

<groupId>org.projectlombok</groupId>

<artifactId>lombok</artifactId>

</dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-thymeleaf</artifactId>

</dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-devtools</artifactId>

<!-- optional=true, 依赖不会传递, 该项目依赖devtools; 之后依赖boot项目的项目如果想要使用devtools,

需要重新引入 -->

</dependency>

</dependencies>

<build>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

<mainClass>com.vv.SpringbootdemoApplication</mainClass>

</configuration>

<goals>

<goal>repackage</goal>

</goals>

</execution>

</executions>

</plugin>

</plugins>

</build>

</project>

三、数据库配置文件（要根据你的工程实际情况作调整，比如账号密码，数据库都应该是自己的）

如果你是application.properties配置文件，就应该这样写：

spring.datasource.driver-class-name: com.mysql.jdbc.Driver  
spring.datasource.url: jdbc:mysql://localhost:3306/springboot?autoReconnect=true&initialTimeout=3&useUnicode=true&characterEncoding=utf-8  
spring.datasource.username: root  
spring.datasource.password: 12345678

如果你是application.yml配置文件，就应该这样写（注意下一层的都是4个空格)

spring:

datasource:  
driver-class-name: com.mysql.jdbc.Driver  
url: jdbc:mysql://localhost:3306/db\_user  
username: root  
password: 123456

**四、代码**

最开始使用mybati比较麻烦，各种配置文件、实体类、dao层映射关联、还有一大推其它配置。当然mybatis也发现了这种弊端，初期开发了generator可以根据表结果自动生产实体类、配置文件和dao层代码，可以减轻一部分开发量；后期也进行了大量的优化可以使用注解了。

于是两种使用方式都介绍一下，一、无配置注解版 二、配置文件版

1.无配置文件注解版

加入配置文件

实验表明，下面两句不要也可以。

mybatis:  
type-aliases-package: cn.saytime.bean

注意此处的cn.saytime.bean是根据你的项目的实际包进行填写的，比如我的是bean是在com.example.demo1包下，所以我的mybatis的配置内容就应该是：

mybatis:  
type-aliases-package: com.example.demo1

\-----------------------------  
**实体类User.class**  
\-----------------------------  
package cn.saytime.bean;  
  
import java.util.Date;  
  
/\*\*  
\* @ClassName cn.saytime.bean.User  
\* @Description  
\* @date 2017-07-04 22:47:28  
\*/

@Getter

@Setter  
public class User \{  
  
private int id;  
private String username;  
private int age;  
private Date ctm;  
  
public User() \{  
\}  
  
public User(String username, int age) \{  
this.username = username;  
this.age = age;  
this.ctm = new Date();  
\}  
\}  
\------------------------------------  
**UserMapper.class**  
\-----------------------------------

@Mapper  
public interface UserMapper \{  
  
@Select("SELECT \* FROM tb\_user WHERE id = \#\{id\}")  
User getUserById(Integer id);  
  
@Select("SELECT \* FROM tb\_user")  
public List<User> getUserList();  
  
@Insert("insert into tb\_user(username, age, ctm) values(\#\{username\}, \#\{age\}, now())")  
public int add(User user);  
  
@Update("UPDATE tb\_user SET username = \#\{user.username\} , age = \#\{user.age\} WHERE id = \#\{id\}")  
public int update(@Param("id") Integer id, @Param("user") User user);  
  
@Delete("DELETE from tb\_user where id = \#\{id\} ")  
public int delete(Integer id);  
\}

\----------------------------  
Mybatis 注解使用 [http://www.mybatis.org/mybatis-3/zh/java-api.html][http_www.mybatis.org_mybatis-3_zh_java-api.html]  
\------------------------------

**UserService.class**  
\------------------------------

package cn.saytime.service;  
  
import cn.saytime.bean.User;  
import org.springframework.stereotype.Service;  
  
import java.util.List;  
  
/\*\*  
\* @ClassName cn.saytime.service.UserService  
\* @Description  
\*/  
public interface UserService \{  
  
User getUserById(Integer id);  
  
public List<User> getUserList();  
  
public int add(User user);  
  
public int update(Integer id, User user);  
  
public int delete(Integer id);  
\}  
\----------------------------------  
**UserServiceimpl.class**  
\----------------------------------

package cn.saytime.service.impl;  
  
import cn.saytime.bean.User;  
import cn.saytime.mapper.UserMapper;  
import cn.saytime.service.UserService;  
import org.springframework.beans.factory.annotation.Autowired;  
import org.springframework.stereotype.Service;  
  
import java.util.List;  
  
/\*\*  
\* @ClassName cn.saytime.service.impl.UserServiceImpl  
\* @Description  
\*/  
@Service(value="userService") //必须是这个，不能是@Service  
public class UserServiceImpl implements UserService \{  
  
@Autowired  
private UserMapper userMapper;  
  
@Override  
public User getUserById(Integer id) \{  
return userMapper.getUserById(id);  
\}  
  
@Override  
public List<User> getUserList() \{  
return userMapper.getUserList();  
\}  
  
@Override  
public int add(User user) \{  
return userMapper.add(user);  
\}  
  
@Override  
public int update(Integer id, User user) \{  
return userMapper.update(id, user);  
\}  
  
@Override  
public int delete(Integer id) \{  
return userMapper.delete(id);  
\}  
\}  
\--------------------------------------------  
**JsonResult.class** **通用json返回类**  
\--------------------------------------------

package cn.saytime.bean;

@Getter

@Setter  
public class JsonResult \{  
  
private String status = null;  
private Object result = null;  
public JsonResult status(String status) \{  
this.status = status;  
return this;  
\}  
  
\}  
\---------------------------------------------  
**UserController.class****（Restful风格）**  
\---------------------------------------------------  
package cn.saytime.web;  
  
import cn.saytime.bean.JsonResult;  
import cn.saytime.bean.User;  
import cn.saytime.service.UserService;  
import org.springframework.beans.factory.annotation.Autowired;  
import org.springframework.http.HttpStatus;  
import org.springframework.http.ResponseEntity;  
import org.springframework.web.bind.annotation.PathVariable;  
import org.springframework.web.bind.annotation.RequestBody;  
import org.springframework.web.bind.annotation.RequestMapping;  
import org.springframework.web.bind.annotation.RequestMethod;  
import org.springframework.web.bind.annotation.RequestParam;  
import org.springframework.web.bind.annotation.RestController;  
  
import java.util.List;  
  
/\*\*  
\* @ClassName cn.saytime.web.UserController  
\* @Description  
\* @date 2017-07-04 22:46:14  
\*/  
@RestController  
public class UserController \{  
  
@Autowired  
private UserService userService;  
  
/\*\*  
\* 根据ID查询用户  
\* @param id  
\* @return  
\*/  
@RequestMapping(value = "user/\{id\}", method = RequestMethod.GET)  
public ResponseEntity<JsonResult> getUserById (@PathVariable(value = "id") Integer id)\{  
JsonResult r = new JsonResult();  
try \{  
User user = userService.getUserById(id);  
r.setResult(user);  
r.setStatus("ok");  
\} catch (Exception e) \{  
r.setResult(e.getClass().getName() + ":" + e.getMessage());  
r.setStatus("error");  
e.printStackTrace();  
\}  
return ResponseEntity.ok(r);  
\}  
  
/\*\*  
\* 查询用户列表  
\* @return  
\*/  
@RequestMapping(value = "users", method = RequestMethod.GET)  
public ResponseEntity<JsonResult> getUserList ()\{  
JsonResult r = new JsonResult();  
try \{  
List<User> users = userService.getUserList();  
r.setResult(users);  
r.setStatus("ok");  
\} catch (Exception e) \{  
r.setResult(e.getClass().getName() + ":" + e.getMessage());  
r.setStatus("error");  
e.printStackTrace();  
\}  
return ResponseEntity.ok(r);  
\}  
  
/\*\*  
\* 添加用户  
\* @param user  
\* @return  
\*/  
@RequestMapping(value = "user", method = RequestMethod.POST)  
public ResponseEntity<JsonResult> add (@RequestBody User user)\{  
JsonResult r = new JsonResult();  
try \{  
int orderId = userService.add(user);  
if (orderId < 0) \{  
r.setResult(orderId);  
r.setStatus("fail");  
\} else \{  
r.setResult(orderId);  
r.setStatus("ok");  
\}  
\} catch (Exception e) \{  
r.setResult(e.getClass().getName() + ":" + e.getMessage());  
r.setStatus("error");  
  
e.printStackTrace();  
\}  
return ResponseEntity.ok(r);  
\}  
  
/\*\*  
\* 根据id删除用户  
\* @param id  
\* @return  
\*/  
@RequestMapping(value = "user/\{id\}", method = RequestMethod.DELETE)  
public ResponseEntity<JsonResult> delete (@PathVariable(value = "id") Integer id)\{  
JsonResult r = new JsonResult();  
try \{  
int ret = userService.delete(id);  
if (ret < 0) \{  
r.setResult(ret);  
r.setStatus("fail");  
\} else \{  
r.setResult(ret);  
r.setStatus("ok");  
\}  
\} catch (Exception e) \{  
r.setResult(e.getClass().getName() + ":" + e.getMessage());  
r.setStatus("error");  
  
e.printStackTrace();  
\}  
return ResponseEntity.ok(r);  
\}  
  
/\*\*  
\* 根据id修改用户信息  
\* @param user  
\* @return  
\*/  
@RequestMapping(value = "user/\{id\}", method = RequestMethod.PUT)  
public ResponseEntity<JsonResult> update (@PathVariable("id") Integer id, @RequestBody User user)\{  
JsonResult r = new JsonResult();  
try \{  
int ret = userService.update(id, user);  
if (ret < 0) \{  
r.setResult(ret);  
r.setStatus("fail");  
\} else \{  
r.setResult(ret);  
r.setStatus("ok");  
\}  
\} catch (Exception e) \{  
r.setResult(e.getClass().getName() + ":" + e.getMessage());  
r.setStatus("error");  
  
e.printStackTrace();  
\}  
return ResponseEntity.ok(r);  
\}  
  
\}  
\----------------------------------------  
**Application.java**  
\----------------------------------------

package cn.saytime;  
  
import org.mybatis.spring.annotation.MapperScan;  
import org.springframework.boot.SpringApplication;  
import org.springframework.boot.autoconfigure.SpringBootApplication;  
  
@SpringBootApplication  
@MapperScan("cn.saytime.mapper")  
public class SpringbootMybaitsApplication \{  
  
public static void main(String\[\] args) \{  
SpringApplication.run(SpringbootMybaitsApplication.class, args);  
\}  
\}

使用PostMan通过测试。

========================================

2.配置文件版

加入配置文件

mybatis:  
mapper-locations: classpath:mybatis/mapper/\*.xml  
config-location: classpath:mybatis/mybatis-config.xml

代码部分，相比于上面那种方式，改变的只有配置文件以及下面几个部分。

\--------------------------------------  
UserMapper.class  
\---------------------------------------

package cn.saytime.mapper;  
  
import cn.saytime.bean.User;  
import org.apache.ibatis.annotations.Delete;  
import org.apache.ibatis.annotations.Insert;  
import org.apache.ibatis.annotations.Param;  
import org.apache.ibatis.annotations.Select;  
import org.apache.ibatis.annotations.Update;  
import org.springframework.stereotype.Repository;  
  
import java.util.List;  
  
/\*\*  
\* @ClassName cn.saytime.mapper.UesrMapper  
\* @Description  
\*/  
@Repository  
public interface UserMapper \{  
  
User getUserById(Integer id);  
  
public List<User> getUserList();  
  
public int add(User user);  
  
public int update(@Param("id") Integer id, @Param("user") User user);  
  
public int delete(Integer id);  
\}  
\---------------------------------------  
mybatis-config.xml  
\-----------------------------------------

<?xml version="1.0" encoding="UTF-8" ?>  
<!DOCTYPE configuration  
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"  
"http://mybatis.org/dtd/mybatis-3-config.dtd">  
<configuration>  
<typeAliases>  
</typeAliases>  
</configuration>  
\---------------------------------------------  
userMapper.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="cn.saytime.mapper.UserMapper" >  
<resultMap id="BaseResultMap" type="cn.saytime.bean.User" >  
<id column="id" property="id" jdbcType="INTEGER" />  
<result column="username" property="username" jdbcType="VARCHAR" />  
<result column="age" property="age" jdbcType="INTEGER" />  
<result column="ctm" property="ctm" jdbcType="TIMESTAMP"/>  
</resultMap>  
  
<sql id="Base\_Column\_List" >  
id, username, age, ctm  
</sql>  
  
<select id="getUserList" resultMap="BaseResultMap" >  
SELECT  
<include refid="Base\_Column\_List" />  
FROM tb\_user  
</select>  
  
<select id="getUserById" parameterType="java.lang.Integer" resultMap="BaseResultMap" >  
SELECT  
<include refid="Base\_Column\_List" />  
FROM tb\_user  
WHERE id = \#\{id\}  
</select>  
  
<insert id="add" parameterType="cn.saytime.bean.User" >  
INSERT INTO  
tb\_user  
(username,age,ctm)  
VALUES  
(\#\{username\}, \#\{age\}, now())  
</insert>  
  
<update id="update" parameterType="java.util.Map" >  
UPDATE  
tb\_user  
SET  
username = \#\{user.username\},age = \#\{user.age\}  
WHERE  
id = \#\{id\}  
</update>  
  
<delete id="delete" parameterType="java.lang.Integer" >  
DELETE FROM  
tb\_user  
WHERE  
id = \#\{id\}  
</delete>  
</mapper>  
\------------------------------

上面这种方式也使用PostMan通过测试。

**五、简要说明**

不知道大家有没有注意到一点，就是引入Springboot-mybatis依赖的时候，并不是spring官方的starter，往常的springboot集成的依赖，比如web，redis等，groupId以及artifactId的地址如下：

<dependency>  
<groupId>org.springframework.boot</groupId>  
<artifactId>spring-boot-starter-web</artifactId>  
</dependency>  
而这里是mybatis为spring提供的starter依赖，所以依赖地址是：

<dependency>  
<groupId>org.mybatis.spring.boot</groupId>  
<artifactId>mybatis-spring-boot-starter</artifactId>  
<version>1.3.0</version>  
</dependency>

而且值得注意的是，这里必须要指定版本号，往常我们使用springboot之所以不需要指定版本号，是因为我们引入的Maven Parent 中指定了SpringBoot的依赖，SpringBoot官方依赖Pom文件中已经指定了它自己集成的第三方依赖的版本号，对于Mybatis，Spring官方并没有提供自己的starter，所以必须跟正常的maven依赖一样，要加版本号。

SpringBoot自己集成的starter依赖，可以查看 [http://docs.spring.io/spring-boot/docs/1.5.4.RELEASE/reference/htmlsingle/\#using-boot-starter][http_docs.spring.io_spring-boot_docs_1.5.4.RELEASE_reference_htmlsingle_using-boot-starter]

[https_blog.csdn.net_saytime_article_details_74783296]: https://blog.csdn.net/saytime/article/details/74783296
[http_www.mybatis.org_mybatis-3_zh_java-api.html]: http://www.mybatis.org/mybatis-3/zh/java-api.html
[http_docs.spring.io_spring-boot_docs_1.5.4.RELEASE_reference_htmlsingle_using-boot-starter]: http://docs.spring.io/spring-boot/docs/1.5.4.RELEASE/reference/htmlsingle/#using-boot-starter