Spring Boot 教程(2)

1. 什么是Mybatis?

MyBatis 是一款优秀的持久层框架，它支持自定义 SQL、存储过程以及高级映射。MyBatis 免除了几乎所有的 JDBC 代码以及设置参数和获取结果集的工作。MyBatis 可以通过简单的 XML 或注解来配置和映射原始类型、接口和 Java POJO（Plain Old Java Objects，普通老式 Java 对象）为数据库中的记录。

2. Spring Boot 整合 Mybatis

2.1 引入maven坐标

<!--springboot父工程-->

    <parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>2.2.2.RELEASE</version>

        <relativePath/> <!-- lookup parent from repository -->

    </parent>

    <dependencies>

        <!--springboot框架web组件-->

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-web</artifactId>

            <version>2.2.2.RELEASE</version>

        </dependency>

        <!--mybatis整合springboot组件-->

        <dependency>

            <groupId>org.mybatis.spring.boot</groupId>

            <artifactId>mybatis-spring-boot-starter</artifactId>

            <version>2.1.0</version>

        </dependency>

        <!--mysql数据库连接驱动-->

        <dependency>

            <groupId>mysql</groupId>

            <artifactId>mysql-connector-java</artifactId>

            <version>8.0.18</version>

        </dependency>

        <!--lombok组件-->

        <dependency>

            <groupId>org.projectlombok</groupId>

            <artifactId>lombok</artifactId>

            <version>1.18.10</version>

        </dependency>

    </dependencies>

    <build>

        <!--springboot的maven插件-->

        <plugins>

            <plugin>

                <groupId>org.springframework.boot</groupId>

                <artifactId>spring-boot-maven-plugin</artifactId>

            </plugin>

            <plugin>

                <groupId>org.apache.maven.plugins</groupId>

                <artifactId>maven-compiler-plugin</artifactId>

                <configuration>

                    <compilerArgs>

                        <arg>-parameters</arg>

                    </compilerArgs>

                </configuration>

            </plugin>

        </plugins>

    </build>

2.2 编写代码

2.2.1 创建如图所示的目录结构

记得两个mapper文件的路径要一致，在编译之后mybatis的映射文件和接口文件才会在同一个目录下。

2.2.2 代码编写

2.2.2.1 创建配置文件和启动类

application.yml：

butterflytri:

  databaseurl-port: 127.0.0.1:3306 # 数据库端口

  database-name: student_db # 数据库名

server:

  port: 8080 # 应用端口

  servlet:

    context-path: /butterflytri # 应用映射

spring:

  application:

    name: mybatis # 应用名称

  datasource:

    url: jdbc:mysql://${butterflytri.databaseurl-port}/${butterflytri.database-name}?useUnicode=true&characterEncoding=UTF-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC

    driver-class-name: com.mysql.jdbc.Driver

    username: root

    password: root

mybatis:

  type-aliases-package: org.wjf.entity # entity别名

  mapper-locations: classpath:org/wjf/mapper/*Mapper.xml # mapper映射包扫描

启动类MybatisApplication.java：

package org.butterflytri;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

/**

 * @author: WJF

 * @date: 2020/5/16

 * @description: MybatisApplication

 */

@SpringBootApplication

public class MybatisApplication {

    public static void main(String[] args) {

        SpringApplication.run(MybatisApplication.class,args);

    }

}

2.2.2.2 创建实体类Student

在entity包下创建Student.java实体类。

package org.butterflytri.entity;

import lombok.Getter;

import lombok.Setter;

import lombok.ToString;

import java.io.Serializable;

/**

 * @author: WJF

 * @date: 2020/5/16

 * @description: Student

 */

@ToString

@Getter

@Setter

public class Student implements Serializable {

    private Long id;

    private String studentName;

    private String studentNo;

    private String sex;

    private Integer age;

}

2.2.2.3 编写mybatis接口文件

在mapper包下创建StudentMapper.java接口。

package org.butterflytri.mapper;

import org.apache.ibatis.annotations.Mapper;

import org.butterflytri.entity.Student;

import java.util.List;

/**

 * @author: WJF

 * @date: 2020/5/16

 * @description:

 */

@Mapper

public interface StudentMapper {

    /**

     * 查询所有学生信息

     * @return List<Student>

     */

    List<Student> findAll();

    /**

     * 通过id查询学生信息

     * @param id

     * @return Student

     */

    Student findOne(Long id);

    /**

     * 通过学号查询学生信息

     * @param studentNo

     * @return Student

     */

    Student findByStudentNo(String studentNo);

}

2.2.2.4 创建mybatis映射文件

在mapper包下创建StudentMapper.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="org.butterflytri.mapper.StudentMapper">

    <sql id="propertyMapper">

        `ID` AS id,

        `STUDENT_NAME` AS studentName,

        `STUDENT_NO` AS studentNo,

        `SEX` AS sex,

        `AGE` AS age

    </sql>

    <select id="findAll" resultType="org.butterflytri.entity.Student">

        SELECT

            <include refid="propertyMapper"></include>

        FROM

            `t_student`

    </select>

    <select id="findOne" parameterType="java.lang.Long" resultType="org.butterflytri.entity.Student">

        SELECT

            <include refid="propertyMapper"></include>

        FROM

            `t_student`

        WHERE

            `ID` = #{id}

    </select>

    <select id="findByStudentNo" parameterType="java.lang.String" resultType="org.butterflytri.entity.Student">

        SELECT

            <include refid="propertyMapper"></include>

        FROM

            `t_student`

        WHERE

            `STUDENT_NO` = #{studentNo}

    </select>

</mapper>

2.2.2.5 Service层

在service包下创建StudentService.java接口，在impl包下创建StudentServiceImpl.Java类并继承StudentService.Java接口。

StudentService.java：

package org.butterflytri.service;

import org.butterflytri.entity.Student;

import java.util.List;

/**

 * @author: WJF

 * @date: 2020/5/16

 * @description: StudentService

 */

public interface StudentService {

    public List<Student> findAll();

    public Student findOne(Long id);

    public Student findByStudentNo(String studentNo);

}

StudentServiceImpl.java：

package org.butterflytri.service.impl;

import org.butterflytri.entity.Student;

import org.butterflytri.mapper.StudentMapper;

import org.butterflytri.service.StudentService;

import org.springframework.stereotype.Service;

import javax.annotation.Resource;

import java.util.List;

/**

 * @author: WJF

 * @date: 2020/5/16

 * @description: StudentServiceImpl

 */

@Service

public class StudentServiceImpl implements StudentService {

    @Resource

    private StudentMapper studentMapper;

    @Override

    public List<Student> findAll() {

        return studentMapper.findAll();

    }

    @Override

    public Student findOne(Long id) {

        return studentMapper.findOne(id);

    }

    @Override

    public Student findByStudentNo(String studentNo) {

        return studentMapper.findByStudentNo(studentNo);

    }

}

2.2.2.6 Controller层

在controller包下创建StudentController.java控制器类。

package org.butterflytri.controller;

import org.butterflytri.entity.Student;

import org.butterflytri.service.StudentService;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

import java.util.List;

/**

 * @author: WJF

 * @date: 2020/5/16

 * @description: StudentController

 */

@RestController

@RequestMapping("/student")

public class StudentController {

    @Resource

    private StudentService studentService;

    @RequestMapping("/findAll")

    public List<Student> findAll() {

        return studentService.findAll();

    }

    @RequestMapping("/findOne")

    public Student findOne(Long id) {

        return studentService.findOne(id);

    }

    @RequestMapping("/findByStudentNo")

    public Student findByStudentNo(String studentNo) {

        return studentService.findByStudentNo(studentNo);

    }

}

2.2.2.7 启动工程，访问路径

启动工程，访问三个接口：

findAll：

findOne：

findByStudentNo：

3. 项目地址

本项目传送门：spring-boot-mybatis

此教程会一直更新下去，觉得博主写的可以的话，关注一下，也可以更方便下次来学习。

巴特西

Spring Boot 教程(2) - Mybatis

1. 什么是Mybatis?

2. Spring Boot 整合 Mybatis

3. 项目地址

最新文章

热门文章