Spring Boot 教程(2) - Mybatis

2020-05-19 16:15:45来源:博客园 阅读 ()

容器云强势上线!快速搭建集群,上万Linux镜像随意使用

Spring Boot 教程(2) - Mybatis

Spring Boot 教程 - Mybatis

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。


原文链接:https://www.cnblogs.com/Butterfly-Tri/p/12902945.html
如有疑问请与原作者联系

标签:参数AVIEClassimgSQL

版权申明:本站文章部分自网络,如有侵权,请联系:west999com@outlook.com
特别注意:本站所有转载文章言论不代表本站观点,本站所提供的摄影照片,插画,设计作品,如需使用,请与原作者联系,版权归原作者所有

上一篇:Spring Boot 教程(1) - HelloWorld

下一篇:Docker搭建代码检测平台SonarQube并检测maven项目