SpringBoot整合Mybatis框架

前期准备——数据库

表

 SQL脚本

-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(255) DEFAULT NULL,
  `password` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

第一步：导包，直接去Maven搜mybatis，可以看到有一个mybatis-spring-boot-starter，点进去将其依赖复制下来，然后粘贴到我们SpringBoot项目的pom.xml文件的中

<!-- mybatis-spring-boot-starter -->
<dependency>
      <groupId>org.mybatis.spring.boot</groupId>
      <artifactId>mybatis-spring-boot-starter</artifactId>
      <version>2.1.4</version>
</dependency>

项目目录结构

 第二步：在springboot的核心配置文件中对Mybatis进行相关配置

这里有对别名和Mybatis中的所有mapper文件的路径进行配置，如有需要，自己可另行配置

#配置数据源
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/springboot?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=123

# 整合mybatis
# 别名
mybatis.type-aliases-package=com.lzp.pojo
# 绑定mapper文件
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml

第三步：编写实体类、接口以及对应的xxxMapper.xml文件，这里我用User业务来举例（同下）

User类

package com.lzp.pojo;

import org.springframework.context.annotation.Bean;
import java.io.Serializable;

/**
 * @Author LZP
 * @Date 2021/4/24 15:17
 * @Version 1.0
 */
public class User implements Serializable {
    private int id;
    private String userName;
    private String password;

    public User() {
    }

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

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

    public int getId() {
        return id;
    }

    public void setId(int 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;
    }


    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", userName='" + userName + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

UserMapper.java

package com.lzp.mapper;

import com.lzp.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
import java.util.List;

/**
 * @Author LZP
 * @Date 2021/4/24 15:17
 * @Version 1.0
 */
// @Mapper这个注解表示该类是一个mybatis的mapper类，Dao
@Mapper
// @Repository这个注解加上，表示该类会被Spring的IOC容器进行托管
@Repository
public interface UserMapper {

    int addUser(User user);

    int deleteUser(int id);

    int updateUser(User user);

    User queryUserById(int id);

    List<User> queryUserList();
}

UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.lzp.mapper.UserMapper">

    <!--  这取User中的属性时，可以直接使用实体类的属性名，不需要通过实体类的类名去点出来  -->
    <insert id="addUser" parameterType="User">
        insert into user (username, password)
        values (#{userName}, #{password})
    </insert>

    <delete id="deleteUser" parameterType="_int">
        delete
        from user
        where id = #{id}
    </delete>

    <update id="updateUser" parameterType="User">
        update user
        set
            username = #{userName},
            password = #{password}
        where id = #{id}
    </update>

    <select id="queryUserById" parameterType="_int" resultType="User">
        select *
        from user
        where id = #{id};
    </select>

    <select id="queryUserList" resultType="User">
        select *
        from user
    </select>
</mapper>

 第四步：编写UserController.java（Controller层）去测试增删改查，这里采用RestFull风格

package com.lzp.controller;

import com.lzp.mapper.UserMapper;
import com.lzp.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;

/**
 * @Author LZP
 * @Date 2021/4/24 15:32
 * @Version 1.0
 *
 * 用户控制层
 * 基本功能：
 * 实现用户的增删改查
 * 请求URL采用了RestFull风格
 */
@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    private UserMapper userMapper;

    @RequestMapping("/queryUserList")
    public List<User> queryUserList() {
        List<User> users = userMapper.queryUserList();
        for (User user : users) {
            System.out.println(user);
        }
        return users;
    }

    @RequestMapping("/queryUserById/{id}")
    public User queryUserById(@PathVariable("id") int id) {
        User user = userMapper.queryUserById(id);
        System.out.println(user);
        return user;
    }

    /**
     * 如需使用RestFull风格，就必须添加@PathVariable这个注解，以保证数据能够正确绑定获取到
     * @param username
     * @param password
     * @return
     */
    @RequestMapping("/addUser/{username}/{password}")
    public String addUser(@PathVariable("username") String username, @PathVariable("password") String password) {
        User user = new User(username, password);
        int result = userMapper.addUser(user);
        if (result > 0) {
            return "成功添加用户";
        }
        return "添加用户失败";
    }

    @RequestMapping("/deleteUser/{id}")
    public String deleteUser(@PathVariable("id") int id) {
        int result = userMapper.deleteUser(id);
        if (result > 0) {
            return "成功删除用户";
        }
        return "删除用户失败";
    }

    @RequestMapping("/updateUser/{id}/{username}/{password}")
    public String updateUser(@PathVariable("id") int id, @PathVariable("username") String username,
                             @PathVariable("password") String password) {
        User user = new User(id, username, password);
        int result = userMapper.updateUser(user);
        if (result > 0) {
            return "成功修改用户";
        }
        return "修改用户失败";
    }
}

最后：浏览器效果如下（只截取了查询所有用户的界面）