SpringBoot.04.SpringBoot整合MyBatis

转x33g5p2x  于2021-09-19 转载在 Spring  
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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

  1. <?xml version="1.0" encoding="UTF-8" ?>
  2. <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
  3. <mapper namespace="com.christy.mapper">
  5. </mapper>

最后点击Apply->OK；如下图所示：

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：

  1. USE `christy`;
  3. /*Table structure for table `t_user` */
  5. DROP TABLE IF EXISTS `t_user`;
  7. CREATE TABLE `t_user` (
  8.   `id` int(6) NOT NULL AUTO_INCREMENT,
  9.   `name` varchar(40) CHARACTER SET utf8 DEFAULT NULL,
  10.   `age` int(3) DEFAULT NULL,
  11.   `salary` double(7,2) DEFAULT NULL,
  12.   PRIMARY KEY (`id`)
  13. ) 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Dependencies中选择Spring Web，点击Finish，如下图所示：

2.pom.xml

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <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">
  3.     <modelVersion>4.0.0</modelVersion>
  4.     <parent>
  5.         <groupId>org.springframework.boot</groupId>
  6.         <artifactId>spring-boot-starter-parent</artifactId>
  7.         <version>2.5.4</version>
  8.         <relativePath/> <!-- lookup parent from repository -->
  9.     </parent>
  11.     <groupId>com.christy</groupId>
  12.     <artifactId>springboot-04-mybatis</artifactId>
  13.     <version>0.0.1-SNAPSHOT</version>
  14.     <name>springboot-04-mybatis</name>
  15.     <description>Demo project for Spring Boot</description>
  17.     <properties>
  18.         <java.version>1.8</java.version>
  19.     </properties>
  21.     <dependencies>
  22.         <!-- spring-boot-starter-web -->
  23.         <dependency>
  24.             <groupId>org.springframework.boot</groupId>
  25.             <artifactId>spring-boot-starter-web</artifactId>
  26.         </dependency>
  28.         <!-- spring-boot-starter-test -->
  29.         <dependency>
  30.             <groupId>org.springframework.boot</groupId>
  31.             <artifactId>spring-boot-starter-test</artifactId>
  32.             <scope>test</scope>
  33.         </dependency>
  35.         <!-- druid -->
  36.         <dependency>
  37.             <groupId>com.alibaba</groupId>
  38.             <artifactId>druid</artifactId>
  39.             <version>1.2.6</version>
  40.         </dependency>
  42.         <!-- mysql-connector-java -->
  43.         <dependency>
  44.             <groupId>mysql</groupId>
  45.             <artifactId>mysql-connector-java</artifactId>
  46.             <version>5.1.38</version>
  47.         </dependency>
  49.         <!-- mybatis-spring-boot-starter 由于springboot整合mybatis版本中默认依赖mybatis 因此不需要额外引入mybati版本,否则会出现冲突 -->
  50.         <dependency>
  51.             <groupId>org.mybatis.spring.boot</groupId>
  52.             <artifactId>mybatis-spring-boot-starter</artifactId>
  53.             <version>2.1.4</version>
  54.         </dependency>
  55.     </dependencies>
  57.     <build>
  58.         <plugins>
  59.             <plugin>
  60.                 <groupId>org.springframework.boot</groupId>
  61.                 <artifactId>spring-boot-maven-plugin</artifactId>
  62.             </plugin>
  63.         </plugins>
  64.     </build>
  66. </project>

3.application.yml

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

4.Springboot04MybatisApplication.java

  1. import org.mybatis.spring.annotation.MapperScan;
  2. import org.springframework.boot.SpringApplication;
  3. import org.springframework.boot.autoconfigure.SpringBootApplication;
  5. /** * * @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 */
  6. @SpringBootApplication
  7. @MapperScan("com.christy.mapper")
  8. public class Springboot04MybatisApplication {
  10.     public static void main(String[] args) {
  11.         SpringApplication.run(Springboot04MybatisApplication.class, args);
  12.     }
  13. }

5.User.java

  1. /** * @Author Christy * @Date 2021/9/2 14:48 **/
  2. public class User {
  3.     private Integer id;
  4.     private String name;
  5.     private Integer age;
  6.     private double salary;
  8.     public User() {
  9.     }
  11.     public User(Integer id, String name, Integer age, double salary) {
  12.         this.id = id;
  13.         this.name = name;
  14.         this.age = age;
  15.         this.salary = salary;
  16.     }
  18.     public Integer getId() {
  19.         return id;
  20.     }
  22.     public void setId(Integer id) {
  23.         this.id = id;
  24.     }
  26.     public String getName() {
  27.         return name;
  28.     }
  30.     public void setName(String name) {
  31.         this.name = name;
  32.     }
  34.     public Integer getAge() {
  35.         return age;
  36.     }
  38.     public void setAge(Integer age) {
  39.         this.age = age;
  40.     }
  42.     public double getSalary() {
  43.         return salary;
  44.     }
  46.     public void setSalary(double salary) {
  47.         this.salary = salary;
  48.     }
  50.     @Override
  51.     public String toString() {
  52.         return "User{" +
  53.                 "id=" + id +
  54.                 ", name='" + name + '\'' +
  55.                 ", age=" + age +
  56.                 ", salary=" + salary +
  57.                 '}';
  58.     }
  59. }

6.UserMapper.java

  1. import com.christy.entity.User;
  2. import org.apache.ibatis.annotations.Mapper;
  4. import java.util.List;
  6. /** * @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 **/
  7. // @Mapper
  8. public interface UserMapper {
  9.     /** * 查找所有用户 * @author Christy * @date 2021/9/2 14:52 * @param * @return java.util.List<User> */
  10.     List<User> findAll();
  11. }

7.UserMapper.xml

  1. <?xml version="1.0" encoding="UTF-8" ?>
  2. <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
  3. <mapper namespace="com.christy.mapper.UserMapper">
  4.     <select id="findAll" resultType="com.christy.entity.User">
  5.         select * from t_user
  6.     </select>
  7. </mapper>

8.UserService

  1. import com.christy.entity.User;
  3. import java.util.List;
  5. /** * @Author Christy * @Date 2021/9/2 14:55 **/
  6. public interface UserService {
  7.     /** * 查询所有用户 * @author Christy * @date 2021/9/2 14:56 * @param * @return java.util.List<com.christy.entity.User> */
  8.     List<User> findAll();
  9. }
  11. import com.christy.entity.User;
  12. import com.christy.mapper.UserMapper;
  13. import com.christy.service.UserService;
  14. import org.springframework.beans.factory.annotation.Autowired;
  15. import org.springframework.stereotype.Service;
  17. import java.util.List;
  19. /** * @Author Christy * @Date 2021/9/2 14:56 **/
  20. @Service
  21. public class UserServiceImpl implements UserService {
  23.     private UserMapper userMapper;
  24.     @Autowired
  25.     public UserServiceImpl(UserMapper userMapper) {
  26.         this.userMapper = userMapper;
  27.     }
  29.     @Override
  30.     public List<User> findAll() {
  31.         return userMapper.findAll();
  32.     }
  33. }

9.UserController.java

  1. import com.christy.entity.User;
  2. import com.christy.service.UserService;
  3. import org.springframework.beans.factory.annotation.Autowired;
  4. import org.springframework.web.bind.annotation.RequestMapping;
  5. import org.springframework.web.bind.annotation.RestController;
  7. import java.util.List;
  9. /** * @Author Christy * @Date 2021/9/2 14:58 **/
  10. @RestController
  11. @RequestMapping("user")
  12. public class UserController {
  14.     private UserService userService;
  15.     @Autowired
  16.     public UserController(UserService userService) {
  17.         this.userService = userService;
  18.     }
  20.     @RequestMapping("findAll")
  21.     public List<User> findAll(){
  22.         return userService.findAll();
  23.     }
  24. }

10.测试

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

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原文链接 : https://blog.csdn.net/bbxylqf126com/article/details/120193369

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