SpringBoot.04.SpringBoot整合MyBatis

喜欢ヅ旅行 2022-09-10 14:14 202阅读 0赞

### SpringBoot.04.SpringBoot整合MyBatis ###

*   *  准备工作
     *   *  1.mapper模板
         *  2.t\_user
     *  整合MyBatis
     *   *  1.新建Module
         *  2.pom.xml
         *  3.application.yml
         *  4.Springboot04MybatisApplication.java
         *  5.User.java
         *  6.UserMapper.java
         *  7.UserMapper.xml
         *  8.UserService
         *  9.UserController.java
         *  10.测试

## 准备工作 ##

### 1.mapper模板 ###

SpringBoot集成MyBatis我们需要新建mapper文件，这里我们先新建一个mapper模板。打开IDEA，依次选择`File`\->`settings`\->`Editor`\->`File and Code Templates`，然后选中`Files`；在`name`中键入`Mapper`、在`Extension`中键入`xml`，将以下内容填到文本框中

最后点击`Apply`\->`OK`；如下图所示：

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5r2u5rGQ5YWI55Sf_size_20_color_FFFFFF_t_70_g_se_x_16]

### 2.t\_user ###

我们使用数据库`christy`中的`t_user`表作为本次使用的数据表，建表语句如下：

USE `christy`;
    
    /*Table structure for table `t_user` */
    
    DROP TABLE IF EXISTS `t_user`;
    
    CREATE TABLE `t_user` (
      `id` int(6) NOT NULL AUTO_INCREMENT,
      `name` varchar(40) CHARACTER SET utf8 DEFAULT NULL,
      `age` int(3) DEFAULT NULL,
      `salary` double(7,2) DEFAULT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8mb4;

## 整合MyBatis ##

### 1.新建Module ###

我们选择`Spring Initializr`的方式新建一个Module，按照下图填写信息后点击`Next`

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5r2u5rGQ5YWI55Sf_size_20_color_FFFFFF_t_70_g_se_x_16 1]  
在`Dependencies`中选择`Spring Web`，点击`Finish`，如下图所示：  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5r2u5rGQ5YWI55Sf_size_20_color_FFFFFF_t_70_g_se_x_16 2]

### 2.pom.xml ###

<?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>2.5.4</version>
            <relativePath/> 
        </parent>
    
        <groupId>com.christy</groupId>
        <artifactId>springboot-04-mybatis</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>springboot-04-mybatis</name>
        <description>Demo project for Spring Boot</description>
    
        <properties>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencies>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
    
            
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>1.2.6</version>
            </dependency>
    
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.38</version>
            </dependency>
    
            
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.1.4</version>
            </dependency>
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    
    </project>

### 3.application.yml ###

server:
      port: 8804
    
    # datasource
    spring:
      datasource:
        type: com.alibaba.druid.pool.DruidDataSource
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://localhost:3306/christy?characterEncoding=UTF-8
        username: root
        password: 123456
    
    # mybatis
    mybatis:
      mapper-locations: classpath:com/christy/mapper/*.xml  #指定mapper配置文件位置
      type-aliases-package: com.christy.entity              #指定起别名所在包

### 4.Springboot04MybatisApplication.java ###

import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    /** * * @author Christy * @date 2021/9/2 14:44 * * @MapperScan 作用在类上，扫描指定包下面的mapper接口 * MapperScan可以根据指定的包名一次性扫描所有的接口 * Mapper只能作用在指定的某个Mapper接口上 */
    @SpringBootApplication
    @MapperScan("com.christy.mapper")
    public class Springboot04MybatisApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(Springboot04MybatisApplication.class, args);
        }
    }

### 5.User.java ###

/** * @Author Christy * @Date 2021/9/2 14:48 **/
    public class User { 
        private Integer id;
        private String name;
        private Integer age;
        private double salary;
    
        public User() { 
        }
    
        public User(Integer id, String name, Integer age, double salary) { 
            this.id = id;
            this.name = name;
            this.age = age;
            this.salary = salary;
        }
    
        public Integer getId() { 
            return id;
        }
    
        public void setId(Integer id) { 
            this.id = id;
        }
    
        public String getName() { 
            return name;
        }
    
        public void setName(String name) { 
            this.name = name;
        }
    
        public Integer getAge() { 
            return age;
        }
    
        public void setAge(Integer age) { 
            this.age = age;
        }
    
        public double getSalary() { 
            return salary;
        }
    
        public void setSalary(double salary) { 
            this.salary = salary;
        }
    
        @Override
        public String toString() { 
            return "User{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    ", age=" + age +
                    ", salary=" + salary +
                    '}';
        }
    }

### 6.UserMapper.java ###

import com.christy.entity.User;
    import org.apache.ibatis.annotations.Mapper;
    
    import java.util.List;
    
    /** * @Author Christy * @Date 2021/9/2 14:50 * 我们已经在入口类上加了注解@MapperScan，这里就不要加注解@Mapper了 **/
    // @Mapper
    public interface UserMapper { 
        /** * 查找所有用户 * @author Christy * @date 2021/9/2 14:52 * @param * @return java.util.List<User> */
        List<User> findAll();
    }

### 7.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="com.christy.mapper.UserMapper">
        <select id="findAll" resultType="com.christy.entity.User">
            select * from t_user
        </select>
    </mapper>

### 8.UserService ###

import com.christy.entity.User;
    
    import java.util.List;
    
    /** * @Author Christy * @Date 2021/9/2 14:55 **/
    public interface UserService { 
        /** * 查询所有用户 * @author Christy * @date 2021/9/2 14:56 * @param * @return java.util.List<com.christy.entity.User> */
        List<User> findAll();
    }
    
    import com.christy.entity.User;
    import com.christy.mapper.UserMapper;
    import com.christy.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    import java.util.List;
    
    /** * @Author Christy * @Date 2021/9/2 14:56 **/
    @Service
    public class UserServiceImpl implements UserService { 
    
        private UserMapper userMapper;
        @Autowired
        public UserServiceImpl(UserMapper userMapper) { 
            this.userMapper = userMapper;
        }
    
        @Override
        public List<User> findAll() { 
            return userMapper.findAll();
        }
    }

### 9.UserController.java ###

import com.christy.entity.User;
    import com.christy.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import java.util.List;
    
    /** * @Author Christy * @Date 2021/9/2 14:58 **/
    @RestController
    @RequestMapping("user")
    public class UserController { 
    
        private UserService userService;
        @Autowired
        public UserController(UserService userService) { 
            this.userService = userService;
        }
    
        @RequestMapping("findAll")
        public List<User> findAll(){ 
            return userService.findAll();
        }
    }

### 10.测试 ###

我们启动项目，浏览器访问`http://localhost:8804/user/findAll`，结果如下：

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5r2u5rGQ5YWI55Sf_size_20_color_FFFFFF_t_70_g_se_x_16 3]

[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5r2u5rGQ5YWI55Sf_size_20_color_FFFFFF_t_70_g_se_x_16]: /images/20220829/91718ba7849a4b1e9e895a075e209f15.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5r2u5rGQ5YWI55Sf_size_20_color_FFFFFF_t_70_g_se_x_16 1]: /images/20220829/39d460207ffa4b4393358393e2d99f21.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5r2u5rGQ5YWI55Sf_size_20_color_FFFFFF_t_70_g_se_x_16 2]: /images/20220829/110081d21d354b619dbd86a998e90714.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5r2u5rGQ5YWI55Sf_size_20_color_FFFFFF_t_70_g_se_x_16 3]: /images/20220829/bb3d79d248a849c791f5a9810a36c372.png