SpringBoot+MySQL+MyBatis的入門教程

本博客 貓叔的博客，轉載請申明出處

本系列教程爲HMStrange項目附帶。

歷史文章

• 如何在VMware12安裝Centos7.6最新版
• Centos7.6安裝Java8
• Centos7.6安裝MySQL+Redis（最新版）

教程內容

備註：本系列開發工具均爲IDEA

1、構建項目，選擇Lombok、Web、MySQL、MyBatis四個基本的Maven依賴。

大家可以看看pom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 http://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>2.1.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.myself.mybatis</groupId>
    <artifactId>datademo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>datademo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</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>2.0.1</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</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>
    </dependencies>

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

</project>

2、準備MySQL，這裏可以參考歷史文章的安裝MySQL環節，我新建了一個數據庫，針對這個項目，構建了一張簡單的表。

DDL

CREATE TABLE `t_msg` (
  `id` int(11) NOT NULL,
  `message` varchar(255) DEFAULT NULL COMMENT '信息',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

3、構建項目目錄，我構建了一個經典的web項目目錄結構，entity實體類、mapper映射、service接口、impl接口實現、controller業務訪問、resources/mapper包用於存放xml

4、填寫application.yml，默認生成不是yml，不過我覺得yml視覺效果好一些，就改了一下，我們需要填寫數據庫信息，還有mybatis的數據庫映射地址，實體類地址

spring:
  datasource:
    url: jdbc:mysql://192.168.192.133:3306/datademo?characterEncoding=utf-8&useSSL=false
    username: root
    password: password
    driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:
  mapper-locations: classpath*:mapper/*Mapper.xml
  type-aliases-package: com.myself.mybatis.entity

5、構建數據庫對應的實體類TMsg，這個類放在entity

package com.myself.mybatis.entity;

import lombok.Data;

import java.io.Serializable;

/**
 * Created by MySelf on 2019/4/9.
 */
@Data
public class TMsg implements Serializable {

    private Integer id;

    private String message;

}

6、構建對應的Mapper接口（其實就類似dao層），這裏與TMsgMapper.xml文件對應關係

package com.myself.mybatis.mapper;

import com.myself.mybatis.entity.TMsg;
import org.apache.ibatis.annotations.Mapper;

/**
 * Created by MySelf on 2019/4/9.
 */
@Mapper
public interface TMsgMapper {

    public TMsg findById(Integer id);

}

<?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.myself.mybatis.mapper.TMsgMapper">
    <select id="findById" resultType="com.myself.mybatis.entity.TMsg">
        SELECT id,message from t_msg WHERE id = #{id}
    </select>
</mapper>

我這邊就單純一個方法，大家可以擴展自己的方法。

7、service層與其實現，這個比較簡單，一般做過web項目的都瞭解

package com.myself.mybatis.service;

import com.myself.mybatis.entity.TMsg;

/**
 * Created by MySelf on 2019/4/9.
 */
public interface TMsgService {

    public TMsg findById(Integer id);

}

package com.myself.mybatis.service.impl;

import com.myself.mybatis.entity.TMsg;
import com.myself.mybatis.mapper.TMsgMapper;
import com.myself.mybatis.service.TMsgService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

/**
 * Created by MySelf on 2019/4/9.
 */
@Service
public class TMsgServiceImpl implements TMsgService {

    @Autowired
    private TMsgMapper tMsgMapper;

    @Override
    public TMsg findById(Integer id) {
        return tMsgMapper.findById(id);
    }
}

8、controller層，我這邊構建了一個get方法，通過id獲取信息。

package com.myself.mybatis.controller;

import com.myself.mybatis.entity.TMsg;
import com.myself.mybatis.service.TMsgService;
import org.apache.ibatis.annotations.Param;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * Created by MySelf on 2019/4/9.
 */
@RestController
@RequestMapping("/msg")
public class TMsgController {

    @Autowired
    private TMsgService tMsgService;

    @GetMapping("/getMsg")
    public String getMsg(@Param("id") Integer id){
        TMsg tMsg = tMsgService.findById(id);
        return tMsg.getMessage();
    }

}

9、啓動項目，並使用Postman測試

10、項目下載地址

歡迎到HMStrange項目進行下載：https://github.com/UncleCatMy...

公衆號：Java貓說

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