springboot 整合Mybatis实战教程

但凡是搞Java开发的，现在应该基本上离不开使用springboot框架，使用框架的过程中肯定离不开操作数据库，目前国内主流的orm框架在Java生态圈中肯定首推Mybatis，虽然网上相关的整合教程还是非常多的，但是爹有娘有到最后还不如自己有，纸上谈兵谁都会，但是在作为一名编程人员，首先必须展示自己的代码，废话不多说，下面展示一个完整的整合案例，包括crud的完整操作，掌握明白应该可以应付公司的基本业务开发了，因此如果还打算在这个领域混，这个案例请必须掌握。

---

项目结构

src
    com.spring.coding
        - controller
            - UserController.java
        - service
            - impl
                UserServiceImpl.java
            - UserService.java
        - mapper
            - UserMapper.java
        - model
            - User.java
resources
    mybatis
        - mapper
            - UserMapper.xml
        mybatis-config.xml
    application.yml

maven依赖

<dependencies>
        //web服务需要的包
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        //springboot和Mybatis整合包
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.3</version>
        </dependency>

        //MySQL驱动包
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
    </dependencies>

application.yml配置

server:
  port: 8080

#MySQL相关配置
spring:
  application:
    name: mybatis-crud
  datasource:
    username: root
    password: root
    url: jdbc:mysql://127.0.0.1:3306/test?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC&autoReconnect=true
    driver-class-name: com.mysql.cj.jdbc.Driver

#mybatis相关配置
mybatis:
  #Mybatis配置文件
  config-location: classpath:mybatis/mybatis-config.xml
  #接口映射文件配置
  mapper-locations: classpath:mybatis/mapper/*.xml
  #实体包映射配置
  type-aliases-package: con.mybatis.springboot_mybatis.model

Mybatis 相关配置文件

1、mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <typeAliases>
        <typeAlias alias="Integer" type="java.lang.Integer" />
        <typeAlias alias="Long" type="java.lang.Long" />
        <typeAlias alias="HashMap" type="java.util.HashMap" />
        <typeAlias alias="LinkedHashMap" type="java.util.LinkedHashMap" />
        <typeAlias alias="ArrayList" type="java.util.ArrayList" />
        <typeAlias alias="LinkedList" type="java.util.LinkedList" />
    </typeAliases>
</configuration>

2、UserMapper.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="com.spring.coding.mapper.UserMapper">

    <resultMap id="UserBaseResultMap" type="com.spring.coding.model.User">
        <id property="id" column="id" javaType="Integer"/>
        <result property="userName" column="username"/>
        <result property="password" column="password"/>
    </resultMap>

    <insert id="add" parameterType="com.spring.coding.model.User">
          insert into user(username, password) values (#{userName}, #{password})
    </insert>

    <delete id="deleteByPrimary" parameterType="java.lang.Integer">
        delete from user where id = #{id}
    </delete>

    <update id="updateByPrimaryKey" parameterType="com.spring.coding.model.User">
        update user set username = #{userName}, password = #{password} where id = #{id}
    </update>

    <select id="selectByPrimaryKey" parameterType="java.lang.Integer" resultMap="UserBaseResultMap">
        select * from user where id = #{id}
    </select>

    <select id="selectByList"  resultMap="UserBaseResultMap">
        select * from user
    </select>
</mapper>

UserMapper.java(dao接口层)

package com.spring.coding.mapper;

import com.spring.coding.model.User;

import java.util.List;

public interface UserMapper {
    /**
     * 添加接口
     * @Param User user
     * @return Int
     */
    int add(User user);


    /**
     * 删除接口
     * @Param Int id
     * @return int
     */
     int deleteByPrimary(Integer id);

    /**
     * 修改接口
     * @Param User user
     * @return int
     */

    int updateByPrimaryKey(User user);


    /**
     *　单条查询接口
     * @Param Integer id
     * @return User
     */
    User selectByPrimaryKey(Integer id);

    /**
     * 批量查询接口
     * @Param User user
     * @return List<User>
     */
    List<User> selectByList();

}

User.java(model层)

package com.spring.coding.model;

public class User {
    private Integer id;

    private String userName;

    private String password;

    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 User() {
    }

    public User(Integer id, String userName, String password) {
        this.id = id;
        this.userName = userName;
        this.password = password;
    }
}

UserService.java(Service层)

package com.spring.coding.service;

import com.spring.coding.model.User;

import java.util.List;

public interface UserService {

    /**
     * 添加接口
     * @Param User user
     * @return Int
     */
    int add(User user);


    /**
     * 删除接口
     * @Param Int id
     * @return int
     */
    int deleteByPrimary(Integer id);

    /**
     * 修改接口
     * @Param User user
     * @return int
     */

    int updateByPrimaryKey(User user);


    /**
     *　单条查询接口
     * @Param Integer id
     * @return User
     */
    User selectByPrimaryKey(Integer id);

    /**
     * 批量查询接口
     * @Param User user
     * @return List<User>
     */
    List<User> selectByList();
}

UserServiceImpl.java(Service实现类)

package com.spring.coding.service.impl;

import com.spring.coding.mapper.UserMapper;
import com.spring.coding.model.User;
import com.spring.coding.service.UserService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.List;

@Service
public class UserServiceImpl implements UserService {

    @Resource
    private UserMapper userMapper;


    @Override
    public int add(User user) {
        return userMapper.add(user);
    }

    @Override
    public int deleteByPrimary(Integer id) {
        return userMapper.deleteByPrimary(id);

    }

    @Override
    public int updateByPrimaryKey(User user) {
        return userMapper.updateByPrimaryKey(user);
    }

    @Override
    public User selectByPrimaryKey(Integer id) {
        return userMapper.selectByPrimaryKey(id);
    }

    @Override
    public List<User> selectByList() {
        return userMapper.selectByList();
    }
}

UserController.java(Controller层)

package com.spring.coding.controller;

import com.spring.coding.model.User;
import com.spring.coding.service.UserService;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;

@RestController
@RequestMapping("/api")
public class UserController {

    @Resource
    private UserService userService;

    /**
     * 添加接口
     * @Param User user
     * @return String
     */

    @PostMapping("/user/add")
    public String addUser(@RequestBody User user) {
        userService.add(user);
        return "add";
    }

    /**
     * 删除接口
     * @Param Int id
     * @return String
     */
    @DeleteMapping("user/del/{id}")
    public String delUser(@PathVariable("id") Integer id){
        userService.deleteByPrimary(id);
        return "delete";
    }

    /**
     * 修改接口
     * @Param User user
     * @return int
     */
    @PutMapping("/user/update")
    public String updateUser(@RequestBody User user){
        userService.updateByPrimaryKey(user);
        return "update";
    }

    /**
     *　单条查询接口
     * @Param Integer id
     * @return User
     */
    @GetMapping("/user/{id}")
    public String findUser(@PathVariable("id") Integer id) {
        userService.selectByPrimaryKey(id);
        return "select user one";
    }

    /**
     * 批量查询接口
     * @Param User user
     * @return List<User>
     */
    @GetMapping("/user/list")
    public String findUserList() {
        userService.selectByList();
        return "select user list";
    }
}

ＣodingApplication.java(主启动类)

package com.spring.coding;

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

@SpringBootApplication
@MapperScan("com.spring.coding.mapper")
public class CodingApplication {

    public static void main(String[] args) {
        SpringApplication.run(CodingApplication.class, args);
    }
}

注意要点

• dao的名称需要与对应的mapper名称一致
• mapper的namespace对应dao的全路径
• dao 声明的方法mapper必须一致相同