mybatis学习(4) - SpringBoot中整合mybatis

前几篇已经简单的学习了mybatis及mbg的简单使用，从此篇文章开始介绍一下mybatis与spring之间的整合及使用，官方的使用文档如下：https://mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/index.html，本文结合官方文档，进行简单整合使用。

创建spring-myBatis项目

打开idea工具，创建spring initializr项目，pom.xml配置文件如下:

<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>4.0.0modelVersion>
    <parent>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-parentartifactId>
        <version>2.7.5version>
        <relativePath/> 
    parent>
    <groupId>io.hxjstudygroupId>
    <artifactId>java-mybatis2-spring-tinyartifactId>
    <version>0.0.1-SNAPSHOTversion>
    <name>java-mybatis2-spring-tinyname>
    <description>java-mybatis2-spring-tinydescription>
    <properties>
        <java.version>11java.version>
    properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-webartifactId>
        dependency>
        <dependency>
            <groupId>org.mybatis.spring.bootgroupId>
            <artifactId>mybatis-spring-boot-starterartifactId>
            <version>2.2.2version>
        dependency>

        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-devtoolsartifactId>
            <scope>runtimescope>
            <optional>trueoptional>
        dependency>
        <dependency>
            <groupId>com.mysqlgroupId>
            <artifactId>mysql-connector-jartifactId>
            <scope>runtimescope>
        dependency>
        <dependency>
            <groupId>org.projectlombokgroupId>
            <artifactId>lombokartifactId>
            <optional>trueoptional>
        dependency>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-testartifactId>
            <scope>testscope>
        dependency>
    dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-maven-pluginartifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombokgroupId>
                            <artifactId>lombokartifactId>
                        exclude>
                    excludes>
                configuration>
            plugin>
        plugins>
    build>
project>
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69

直接启动项目，报错如下：

***************************
APPLICATION FAILED TO START
***************************

Description:

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.

Reason: Failed to determine a suitable driver class


Action:

Consider the following:
	If you want an embedded database (H2, HSQL or Derby), please put it on the classpath.
	If you have database settings to be loaded from a particular profile you may need to activate it (no profiles are currently active).


Process finished with exit code 0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

为什么报错，由于我们集成了mybatis项目，但是我们并没有给到他数据源的配置，所以系统就告诉我们，你没配置数据源啊，我启动不了了。虽然可以使用排除启动类的方式：

@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
1

来消除错误。

配置Springboot应用文件

在application.properties文件中添加数据源信息，如下：

# 数据库配置
spring.datasource.url = jdbc:mysql://localhost:3388/db_ddyx?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
spring.datasource.username = root
spring.datasource.password = root

# 查看查询日志
mybatis.configuration.log-impl = org.apache.ibatis.logging.stdout.StdOutImpl
1
2
3
4
5
6
7

现在可以正常启动，但是我们还未使用mybatis框架，接下来开始使用框架来查询数据。

编写应用代码(Mapper/Model/Controller)

我们使用最简单的查询Mapper接口，查询语句直接使用注解的方式实现如下：

package io.hxjstudy.javamybatis2springtiny.mapper;

import io.hxjstudy.javamybatis2springtiny.model.UserInfo;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;

@Mapper
public interface UserMapper {
    @Select("SELECT * FROM g2_user limit 1")
    UserInfo findOne();
}
1
2
3
4
5
6
7
8
9
10
11

创建一个返回model类，UserInfo，代码如下：

package io.hxjstudy.javamybatis2springtiny.model;

import lombok.Data;

@Data
public class UserInfo {
    //protected String
    protected String uid;
    protected String unick;
}
1
2
3
4
5
6
7
8
9
10

代码中我们使用了lombok插件，具体的lombok使用，请参考：https://projectlombok.org/。接下来创建一个最简单的controller来访问:

package io.hxjstudy.javamybatis2springtiny.controller;

import io.hxjstudy.javamybatis2springtiny.mapper.UserMapper;
import io.hxjstudy.javamybatis2springtiny.model.UserInfo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserMapper userMapper;

    @RequestMapping(value = "get_one", method = RequestMethod.GET)
    @ResponseBody
    public UserInfo getOne(){
        UserInfo one = userMapper.findOne();
        System.out.println(one);
        return one;
    }
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

从上面可以看出，我们使用@autowired自动注入userMapper，当然实际生产中一般会有service层来进行更复杂的逻辑处理，此处为了方便使用，简单分层。

启动应用并访问

点击应用启动：

2022-11-04 18:10:36.087  INFO 15757 --- [  restartedMain] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1215 ms
Logging initialized using 'class org.apache.ibatis.logging.stdout.StdOutImpl' adapter.
Property 'mapperLocations' was not specified.
2022-11-04 18:10:36.549  INFO 15757 --- [  restartedMain] o.s.b.d.a.OptionalLiveReloadServer       : LiveReload server is running on port 35729
2022-11-04 18:10:36.575  INFO 15757 --- [  restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2022-11-04 18:10:36.585  INFO 15757 --- [  restartedMain] i.h.j.JavaMybatis2SpringTinyApplication  : Started JavaMybatis2SpringTinyApplication in 2.299 seconds (JVM running for 3.075)
1
2
3
4
5
6

访问路径：http://localhost:8080/user/get_one，控制台输出如下：

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@67fea111] was not registered for synchronization because synchronization is not active
2022-11-04 18:19:17.818  INFO 15757 --- [nio-8080-exec-1] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2022-11-04 18:19:18.161  INFO 15757 --- [nio-8080-exec-1] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
JDBC Connection [HikariProxyConnection@1542062776 wrapping com.mysql.cj.jdbc.ConnectionImpl@18ed7b11] will not be managed by Spring
==>  Preparing: SELECT * FROM g2_user limit 1
==> Parameters: 
<==    Columns: uid, unick
<==        Row: 10010323, 152****2082
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@67fea111]
UserInfo(uid=10010323, unick=152****2082)
1
2
3
4
5
6
7
8
9
10
11
12

界面返回数据：

{"uid":"10010323","unick":"152****2082"}
1

至此基于org.mybatis.spring.boot整合mybatis的基本使用已实现，实际生产中我们都会使用xml映射文件查询，下面继续学习如何使用映射文件查询。

spring中mybatis的配置

在官网的配置说明中：https://mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/index.html，有关于mybatis的详细配置说明：

官方参考sample

更详细的参考，可以查看官方提供各种场景例子：https://github.com/mybatis/spring-boot-starter

同样，放上学习代码地址：https://github.com/redrockfinch/java-mybatis2-spring-tiny