mybatis入门案例-传参类型和方式

mybatis传参类型和方式

主要分享一下mybatis的mapper接口参数类型和传参方式，适用于初学者。

直接上代码：

pom.xml文件

<?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>3.3.4</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>demo</description>
    <url/>

    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <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>3.0.3</version>
        </dependency>

        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter-test</artifactId>
            <version>3.0.3</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

application.yml文件

spring:
  datasource:
    username: root
    password: ******
    url: jdbc:mysql:///数据库名
    driver-class-name: com.mysql.jdbc.Driver
mybatis:
  mapper-locations: classpath:mapper/*Mapper.xml
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

实体类：User

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {

    private Integer id;
    private String username;
    private String password;
    private String email;
}

mapper接口

public interface UserMapper {

    /**
     * 只有一个参数
     * 根据用户id查询用户
     * @param id
     * @return
     */
    User querybyId(Integer id);

    /**
     * 有两个参数
     * 根据用户名和密码查询用户
     * @param username
     * @param password
     * @return
     */
    User querybyUsernameAndPassword(@Param("username") String username, @Param("password") String password);

    /**
     * 有一个对象参数
     * 根据用户对象查询用户
     * @param user
     * @return
     */
    User querybyUser(User user);

    /**
     * 有一个map参数
     * 根据map查询用户
     * @param maps
     * @return
     */
    User querybyMap(Map<String,String> maps);

    /**
     * 有一个list集合参数
     * 批量添加
     * @param users
     */
    void batchInsert(@Param("users") List<User> users);
}

mapper.xml文件

<?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.example.demo.mapper.UserMapper">

    <!-- 根据用户ID查询用户 -->
    <select id="querybyId" resultType="com.example.demo.domain.User">
        SELECT * FROM user WHERE id = #{id}
    </select>

    <!-- 根据用户名和密码查询用户 -->
    <select id="querybyUsernameAndPassword" resultType="com.example.demo.domain.User">
        SELECT * FROM user WHERE username = #{username} AND password = #{password}
    </select>

    <!-- 根据用户对象查询用户 -->
    <select id="querybyUser" resultType="com.example.demo.domain.User">
        SELECT * FROM user WHERE username = #{username} AND password = #{password}
    </select>

    <!-- 根据map查询用户 -->
    <select id="querybyMap" resultType="com.example.demo.domain.User">
        SELECT * FROM user
        <where>
            <if test="'username' !=null">
                AND username = #{username}
            </if>
            <if test="'password' !=null">
                AND password = #{password}
            </if>
        </where>

    </select>

    <!-- 批量添加用户 -->
    <insert id="batchInsert">
        INSERT INTO user (username, password,email) VALUES
        <foreach item="user" index="index" collection="users" open="(" separator="),(" close=")">
            #{user.username}, #{user.password}, #{user.email}
        </foreach>
    </insert>

</mapper>

测试

@SpringBootTest
class DemoApplicationTests {

    @Autowired
    private UserMapper userMapper;

    @Test
    void contextLoads() {

        System.out.println(userMapper.querybyId(1));
    }

    @Test
    void querybyUsernameAndPassword() {
        System.out.println(userMapper.querybyUsernameAndPassword("tom", "123"));
    }

    @Test
    void querybyUser() {
        System.out.println(userMapper.querybyUser(new User(null, "tom", "123", null)));
    }

    @Test
    void querybyMap() {
        System.out.println(userMapper.querybyMap(new HashMap<String, String>(){{
            put("username","tom"); put("password","123");
        }}));
    }

    @Test
    void batchInsert() {
        userMapper.batchInsert(new ArrayList<User>(){{
            add(new User(null,"tom3","123","[email protected]"));
            add(new User(null,"tom4","123","[email protected]"));
        }});
    }

}

完结，撒花！ 希望对各位初学者有帮助，感觉点赞关注。