springboot+mybatis基本环境搭建

SpringBoot整合Mybatis环境搭建：

1.创建工程springboot_mybatis，导入依赖：包含父工程，web起步依赖，mysql驱动以及mybatis起步依赖
    <?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>

        <groupId>com.it</groupId>
        <artifactId>springboot_mybatis</artifactId>
        <version>1.0-SNAPSHOT</version>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.1.4.RELEASE</version>
        </parent>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>

            <!--测试起步依赖-->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            <!--添加依赖：MySQL驱动，springboot整合mybatis-->
            <!--驱动-->
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
            </dependency>
            <!--mybatis的 起步依赖-->
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.0.1</version>
            </dependency>
        </dependencies>


    </project>
    
2.创建启动类：使用@MapperScan指定要扫描的包
    package com.it;

    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;

    /**
     * 启动类
     *
     * @author Lyle
     * @date 2020/7/11
     */
    @SpringBootApplication
    @MapperScan(basePackages = "com.it.dao")
    public class SpringBootMybatisApplication {
        public static void main(String[] args) {
            SpringApplication.run(SpringBootMybatisApplication.class,args);
        }
    }
    
3.配置springboot配置文件：数据源，mybatis映射文件位置，应用名称以及应用端口号；
    spring:
      datasource:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://localhost/springboot_user?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
        username: root
        password: root
      #配置mapper的映射文件的位置，配置该配置后，接口包路径和映射文件包路径可以不一致
      mybatis:
        mapper-locations: classpath:mappers/*Mapper.xml
      application:
        name: user
    server:
      port: 25501
      
4.数据库表：
    CREATE TABLE `user` (
      `id` int(11) NOT NULL AUTO_INCREMENT,
      `username` varchar(50) DEFAULT NULL,
      `password` varchar(50) DEFAULT NULL,
      `name` varchar(50) DEFAULT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;
    
5.数据库表对应的实体类：
    package com.it.pojo;

    import java.io.Serializable;

    /**
     * ToDo
     *
     * @author Lyle
     * @date 2020/4/1
     */
    public class User implements Serializable {
        private Integer id;
        private String username;//用户名
        private String password;//密码
        private String name;//姓名

        public Integer getId() {
            return id;
        }

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

        public String getUsername() {
            return username;
        }

        public void setUsername(String username) {
            this.username = username;
        }

        public String getPassword() {
            return password;
        }

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

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }
    }
    
6.典型的三层架构：controller,service,dao
    6.1 controller层：
        package com.it.controller;

        import com.it.pojo.User;
        import com.it.service.IUserService;
        import org.springframework.beans.factory.annotation.Autowired;
        import org.springframework.web.bind.annotation.RequestMapping;
        import org.springframework.web.bind.annotation.RestController;

        import java.util.List;

        /**
         * ToDo
         *
         * @author Lyle
         * @date 2020/7/11
         */
        @RestController
        @RequestMapping(value = "/user")
        public class UserController {

            @Autowired
            private IUserService userService;
            @RequestMapping(value = "/findAll")
            public List<User> findList(){
                return userService.findList();
            }
        }
    6.2 service接口及其实现类：
        接口：
        package com.it.service;

        import com.it.pojo.User;

        import java.util.List;

        /**
         * ToDo
         *
         * @author Lyle
         * @date 2020/7/11
         */
        public interface IUserService {
            List<User> findList();
        }
        
        实现类：
        package com.it.service.impl;

        import com.it.dao.UserMapper;
        import com.it.pojo.User;
        import com.it.service.IUserService;
        import org.springframework.beans.factory.annotation.Autowired;
        import org.springframework.stereotype.Service;

        import java.util.List;

        /**
         * ToDo
         *
         * @author Lyle
         * @date 2020/7/11
         */
        @Service
        public class UserService implements IUserService {

            @Autowired
            private UserMapper userMapper;


            @Override
            public List<User> findList() {
                return userMapper.findAll();
            }
        }
        
    6.3 dao接口及xml文件：
        dao接口：
        package com.it.dao;

        import com.it.pojo.User;
        import org.springframework.stereotype.Repository;

        import java.util.List;

        /**
         * ToDo
         *
         * @author Lyle
         * @date 2020/4/1
         */
        @Repository
        public interface UserMapper {

            public List<User> findAll();
        }
        
        xml映射文件：
            <?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.it.dao.UserMapper">
                <select id="findAll" resultType="com.it.pojo.User">
                    SELECT * from user
                </select>
            </mapper>

调用接口测试：打开浏览器，输入http://localhost:25501/user/findAll