SpringBoot第三篇SpringBoo和Mybatis整合

1、新建springboot项目，选择mysql、jdbc、web，使用maven管理项目

2、检查pom.xml依赖，已经添加了mybatis、spring-boot、junit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 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>2.5.6</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>cn.yinmingneng</groupId>
    <artifactId>springboot1028001</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot1028001</name>
    <description>springboot1028001</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.0</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

　　

3、编写映射实体，user

public class user {
    private Integer id;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUser_id() {
        return user_id;
    }

    public void setUser_id(String user_id) {
        this.user_id = user_id;
    }

    public String getUser_name() {
        return user_name;
    }

    public void setUser_name(String user_name) {
        this.user_name = user_name;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    private String user_id;
    private  String user_name;
    private String password;
    private  String email;
}

4、编写仓储接口，一定要写成接口，他自动生成实现类

@Repository
public interface UserMapper  {
    List<user> GetUserById();
}

5、编写xml文件，定义sql语句

<?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.yinmingneng.springboot1028001.Mapper.UserMapper">
    <select id="GetUserById" resultType="cn.yinmingneng.springboot1028001.Entities.user">
        select * from user
    </select>
</mapper>

xml文件放在resources文件夹下的mapping文件下下

6、应用程序启动配置，我使用了yml文件，读起来方便，一定要配置spring的daatasource否则会报错，mybatis的获取xml文件的路径，

typeAliasesPackage:类的别名

server:
  port: 8095

Spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/5555?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
    driver-class-name: com.mysql.jdbc.Driver

mybatis:
  mapper-locations: classpath:Mapping/*.xml
  //typeAliasesPackage:cn.yinmingneng.springboot1028001.Mapper

7、启动程序配置扫描包,如果不配置扫描包的路径会找不到这些接口

@MapperScan("cn.yinmingneng.springboot1028001.Mapper")

 Field userMapper in cn.yinmingneng.springboot1028001.Services.UserServices required a bean of type 'cn.yinmingneng.springboot1028001.Mapper.UserMapper' that could not be found.

8、测试、启动测试