Spring Boot Mybatis 入门示例

基于Spring Boot 2.3.4，Junit5

步骤说明

整个工程的最终目录结构如下，添加文件或者新建的目录的参考：

└─src├─main│  ├─java│  │  └─com│  │      └─mall│  │          └─MallWeb│  │              ├─controllers│  │              ├─mapper│  │              ├─model│  │              └─services│  └─resources│      └─mybatis│          └─mapper└─test└─java└─com└─mall└─MallWeb└─mapper

数据库初始化语句

数据库表的初始化语句全部在下面，也可以根据自己的情况进行修改

CREATE DATABASE  IF NOT EXISTS `mall`;USE `mall`;CREATE TABLE IF NOT EXISTS `users` (`id` int(11) NOT NULL AUTO_INCREMENT,`name` varchar(16) NOT NULL,`password` varchar(16) NOT NULL,`phoneNumber` varchar(15) NOT NULL,`money` int(11) NOT NULL,PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=latin1;

build.gradle：依赖添加

需要添加下面依赖

‘mysql:mysql-connector-java:8.0.14’
‘org.mybatis.spring.boot:mybatis-spring-boot-starter:2.0.0’
‘org.projectlombok:lombok:1.16.16’

dependencies {implementation 'org.springframework.boot:spring-boot-starter-web'//  MySQL数据库需要implementation 'mysql:mysql-connector-java:8.0.14'//    spring mybatisimplementation 'org.mybatis.spring.boot:mybatis-spring-boot-starter:2.0.0'//    lombok,用于Entity的自动get和set方法生成，不用自己写一大推的get和set方法implementation 'org.projectlombok:lombok:1.16.16'testImplementation('org.springframework.boot:spring-boot-starter-test') {exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'}
}

application.properties：配置添加

配置文件的编写需要注意参数的配置，比如SSL那个一般要设置为false，driver-class-name也要注意一下，不要写错了，文件的大致内容如下：

# mybatis的config文件位置配置
mybatis.config-location=classpath:mybatis/mybatis-config.xml
# 各个表的xml文件位置配置
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml
mybatis.type-aliases-package=com.neo.model# 数据库连接信息配置，自行更换数据库，用户名和密码
spring.datasource.url=jdbc:mysql://localhost:3306/mall?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8\&useSSL=false
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver#springboot + mybatis设置将SQL语句打印到控制台
logging.level.com.mall.MallWeb.mapper=debug

代码编写

入口环境配置Mapper扫描配置

在入口函数添加Mapper扫描配置，这样不必在每个Mapper上加上Mapper注解，大致如下：

package com.mall.MallWeb;import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;/*** @author lw*/
@SpringBootApplication
@MapperScan("com.mall.MallWeb.mapper")
public class MallWebApplication {public static void main(String[] args) {SpringApplication.run(MallWebApplication.class, args);}}

编写实体类

在代码目录下创建model文件夹，用于存储实体（数据库表）。编辑实体类，大致如下：

ppackage com.mall.MallWeb.model;import java.io.Serializable;/*** @author lw*/
public class User implements Serializable {private Long id;private String name;private String password;private String phoneNumber;private Long money;public User(String name, String password, String phoneNumber) {this.name = name;this.password = password;this.phoneNumber = phoneNumber;this.money = 0L;}@Overridepublic String toString() {return id + "::" + name + "::" + password + "::" + phoneNumber + "::" + money;}public Long getId() {return id;}public void setId(Long id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getPhoneNumber() {return phoneNumber;}public void setPhoneNumber(String phoneNumber) {this.phoneNumber = phoneNumber;}public Long getMoney() {return money;}public void setMoney(Long money) {this.money = money;}}

Mapper接口类

新建Mapper文件夹，里面放Mapper相关的接口类。编写Mapper接口类，大致内容如下，@Repository解决idea里面的bean使用错误

package com.mall.MallWeb.mapper;import com.mall.MallWeb.model.User;
import org.springframework.stereotype.Repository;import java.util.List;/*** @author lw*/
@Repository
public interface UserMapper {List<User> queryAll();User queryOne(Long id);void add(User user);void update(User user);
}

Mytatis配置文件mybatis-config.xml

新建文件夹 resource/mybatis，下面新建：mybatis-config.xml 文件，写入下面的内容：

<?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><typeAlias alias="Integer" type="java.lang.Integer" /><typeAlias alias="Long" type="java.lang.Long" /><typeAlias alias="HashMap" type="java.util.HashMap" /><typeAlias alias="LinkedHashMap" type="java.util.LinkedHashMap" /><typeAlias alias="ArrayList" type="java.util.ArrayList" /><typeAlias alias="LinkedList" type="java.util.LinkedList" /></typeAliases>
</configuration>

表users查询配置文件User.xml

新建文件夹 resouce/mybatis/mapper,新建文件：User.xml，输入下面的内容：

<?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.mall.MallWeb.mapper.UserMapper" ><resultMap id="BaseResultMap" type="com.mall.MallWeb.model.User" ><id column="id" property="id" jdbcType="BIGINT" /><result column="name" property="name" jdbcType="VARCHAR" /><result column="password" property="password" jdbcType="VARCHAR" /><result column="phoneNumber" property="phoneNumber" jdbcType="VARCHAR"/><result column="money" property="money" jdbcType="BIGINT" /></resultMap><sql id="Base_Column_List" >id, name, password, phoneNumber, money</sql><insert id="add" parameterType="com.mall.MallWeb.mapper.UserMapper" useGeneratedKeys="true" keyProperty="id">INSERT INTOusers(name, password, phoneNumber, money)VALUES(#{name}, #{password}, #{phoneNumber}, #{money})</insert><update id="update" parameterType="com.mall.MallWeb.model.User">UPDATEusersSET<trim suffixOverrides="," suffix="WHERE id = #{id}"><if test="name != null">name = #{name},</if><if test="password != null">password = #{password},</if><if test="phoneNumber != null">phoneNumber = #{phoneNumber},</if><if test="money != null">money = #{money},</if></trim></update><select id="queryAll" resultMap="BaseResultMap">SELECT<include refid="Base_Column_List" />FROM users</select><select id="queryOne" resultType="com.mall.MallWeb.model.User" parameterType="java.lang.Long">SELECT<include refid="Base_Column_List" />FROM usersWHERE id = #{id}</select></mapper>

测试文件UserMapperTest

大致打代码如下：

在Junit5中没有了RunWith，换成了ExtendWith。测试中使用了真实的数据库，所有开启了测试后的数据回滚，避免测试数据进入数据库

package com.mall.MallWeb.mapper;import com.mall.MallWeb.model.User;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit.jupiter.SpringExtension;
import org.springframework.transaction.annotation.Transactional;import java.util.List;@ExtendWith(SpringExtension.class)
@SpringBootTest
public class UserMapperTest {@Autowiredprivate UserMapper userMapper;@Test@Transactionalpublic void addUserTest() {User user = new User("testUser", "testPassword", "testPhone");userMapper.add(user);assert userMapper.queryAll().size() != 0;}@Testpublic void queryTest() {List<User> users = userMapper.queryAll();assert users.size() != 0;for (User user: users) {System.out.println(user.toString());}}@Test@Transactionalpublic void updateTest() {User user = new User("testUser", "testPassword", "testPhone");userMapper.add(user);System.out.println(user.toString());User newUser = userMapper.queryOne(user.getId());System.out.println(newUser.toString());newUser.setName("updateUser");System.out.println(newUser.toString());userMapper.update(newUser);System.out.println(newUser.toString());User queryUser = userMapper.queryOne(user.getId());assert queryUser.getName().equals("updateUser");}
}

controllers目录下视图文件：UserController.java

package com.mall.MallWeb.controllers;import com.mall.MallWeb.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.HashMap;
import java.util.Map;/*** 用户*/
@RestController
@RequestMapping("/user")
public class UserController {@Autowiredprivate UserMapper userMapper;@GetMapping("/users")public Map users() {Map response = new HashMap();response.put("status", "success");response.put("users", userMapper.queryAll());return response;}
}

启动与测试

现在开始运行程序，使用浏览器访问链接：http://localhost:8080/user/users

能看到有数据或者没有数据都是成功的（下面的数据是提前插入的）

{"users": [{"id": 6,"name": "testUser","password": "testPasspword","phoneNumber": "testPhone","money": 0},{"id": 7,"name": "testUser","password": "testPasspword","phoneNumber": "testPhone","money": 0},{"id": 8,"name": "testUser","password": "testPasspword","phoneNumber": "testPhone","money": 0},{"id": 9,"name": "testUser","password": "testPasspword","phoneNumber": "testPhone","money": 0},{"id": 10,"name": "testUser","password": "testPassword","phoneNumber": "testPhone","money": 0},{"id": 11,"name": "testUser","password": "testPassword","phoneNumber": "testPhone","money": 0},{"id": 12,"name": "testUser","password": "testPassword","phoneNumber": "testPhone","money": 0}],"status": "success"
}

参考链接

Spring boot 启动报错-Reason Failed to determine a suitable driver class
java连接mysql失败Path does not chain with any of the trust anchors
SpringBoot+Mybatis框架项目的单元测试和集成测试（下）
Spring Boot(六)：如何优雅的使用 Mybatis
mybatis-spring-boot-test-autoconfigure
Idea inspects batis mapper bean wrong
Property ‘sqlSessionFactory’ or ‘sqlSessionTemplate’ are required in spring mock mvc test for spring boot with mybatis
mybatis传入多个参数
MyBatis多参数传递之Map方式示例——MyBatis学习笔记之十三
MyBatis多参数传递的四种方式
Mybatis 开启控制台打印sql语句