Spring Boot入门(七)：使用MyBatis访问MySql数据库(xml方式)

本系列博客带你一步一步的学习spring boot，如帮助到你，不胜荣幸，如有错误，欢迎指正！

本篇博客我们讲解下在spring boot中使用mybatis访问mysql数据库（xml方式）的简单用法。

本系列其它文章如下所示：

spring boot入门(一)：使用idea创建spring boot项目并使用yaml配置文件

spring boot入门(二)：使用profile实现多环境配置管理&如何获取配置文件值

spring boot入门(三)：使用scheduled注解实现定时任务

spring boot入门(四)：开发web api接口常用注解总结

spring boot入门(五)：使用jdbc访问mysql数据库

spring boot入门(六)：使用mybatis访问mysql数据库(注解方式)

1. 前期准备

假设你的机器已经安装好了mysql，我们先执行如下语句创建数据库和表：

create database springbootaction_db;

create table author
(
  author_id   int auto_increment comment '作者id' primary key,
  author_name varchar(20) not null comment '姓名',
  pen_name    varchar(20) not null comment '笔名'
)
comment '作者';

2. 修改pom文件

pom文件引入mybatis的starter pom和mysql的驱动，因后面要编写控制器，因此也引入下阿里巴巴的fastjson：

<dependency>
    <groupid>org.mybatis.spring.boot</groupid>
    <artifactid>mybatis-spring-boot-starter</artifactid>
    <version>1.1.1</version>
</dependency>

<dependency>
    <groupid>mysql</groupid>
    <artifactid>mysql-connector-java</artifactid>
    <version>5.1.35</version>
</dependency>
<dependency>
    <groupid>com.alibaba</groupid>
    <artifactid>fastjson</artifactid>
    <version>1.2.47</version>
</dependency>

说明：引入了mybatis-spring-boot-starter后，可以不再引用spring-boot-starter-jdbc,因为前者已经依赖于后者。

3. 配置数据源

在resources/application.yml中配置数据源：

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.driver
    url: jdbc:mysql://localhost:3306/springbootaction_db
    username: root
    password:

4. 修改配置文件

在application.yml中添加mybatis配置：

mybatis:
  mapper-locations: classpath:mybatis/*.xml
  type-aliases-package: com.zwwhnly.springbootaction.mybatis.entity

其中，mapper-locations为mybatis xml文件的路径，type-aliases-package为定义的实体所在的包名。

5. 定义数据库实体

定义数据库实体author：

package com.zwwhnly.springbootaction.mybatis.entity;

import com.alibaba.fastjson.annotation.jsonfield;

public class author {
    @jsonfield(name = "author_id")
    private integer authorid;
    @jsonfield(name = "author_name")
    private string authorname;
    @jsonfield(name = "pen_name")
    private string penname;

    public integer getauthorid() {
        return authorid;
    }

    public void setauthorid(integer authorid) {
        this.authorid = authorid;
    }

    public string getauthorname() {
        return authorname;
    }

    public void setauthorname(string authorname) {
        this.authorname = authorname;
    }

    public string getpenname() {
        return penname;
    }

    public void setpenname(string penname) {
        this.penname = penname;
    }
}

6. 编写dao层代码

定义接口authormapperv2：

package com.zwwhnly.springbootaction.mybatis.xml;

import com.zwwhnly.springbootaction.mybatis.entity.author;
import org.apache.ibatis.annotations.mapper;
import org.apache.ibatis.annotations.param;

import java.util.list;

@mapper
public interface authormapperv2 {

    int add(@param("author_name") string authorname, @param("pen_name") string penname);

    int update(@param("author_name") string authorname, @param("pen_name") string penname, @param("id") integer id);

    int delete(integer id);

    author findauthor(@param("id") integer id);

    list<author> findauthorlist();
}

注意：接口要添加@mapper注解。

7. 编写service层代码

定义类authorservicev2：

package com.zwwhnly.springbootaction.mybatis.xml;

import com.zwwhnly.springbootaction.mybatis.entity.author;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.stereotype.service;

import java.util.list;

@service
public class authorservicev2 {
    @autowired
    private authormapperv2 authormapperv2;

    public int add(string authorname, string penname) {
        return this.authormapperv2.add(authorname, penname);
    }

    public int update(string authorname, string penname, integer id) {
        return this.authormapperv2.update(authorname, penname, id);
    }

    public int delete(integer id) {
        return this.authormapperv2.delete(id);
    }

    public author findauthor(integer id) {
        return this.authormapperv2.findauthor(id);
    }

    public list<author> findauthorlist() {
        return this.authormapperv2.findauthorlist();
    }
}

注意：类添加@service注解。

8. 添加mybatis xml文件

在resources目录下，新建mybatis文件夹，然后新建authormapper.xml文件，分别实现上面定义的新增，修改，删除，获取单个作者信息，获取作者列表功能：

<?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.zwwhnly.springbootaction.mybatis.xml.authormapperv2">
    <resultmap id="authormap" type="author">
        <result property="authorid" column="author_id"/>
        <result property="authorname" column="author_name"/>
        <result property="penname" column="pen_name"/>
    </resultmap>

    <insert id="add">
        insert into author(author_name, pen_name)
        values(#{author_name}, #{pen_name});
    </insert>
    <update id="update">
        update author
        set author_name = #{author_name,jdbctype=varchar},
        pen_name = #{pen_name,jdbctype=varchar}
        where author_id = #{id,jdbctype=integer};
    </update>
    <delete id="delete">
        delete from author
        where author_id = #{id};
    </delete>
    <select id="findauthor" resultmap="authormap" resulttype="author">
       select author_id, author_name, pen_name
       from author
       where author_id = #{id};
    </select>
    <select id="findauthorlist" resultmap="authormap">
        select author_id, author_name, pen_name
        from author;
    </select>
</mapper>

9. 编写controller代码

新建控制器authorcontrollerv2：

package com.zwwhnly.springbootaction.controller;

import com.alibaba.fastjson.jsonobject;
import com.zwwhnly.springbootaction.mybatis.entity.author;
import com.zwwhnly.springbootaction.mybatis.xml.authorservicev2;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.web.bind.annotation.*;

import java.util.hashmap;
import java.util.list;
import java.util.map;

@restcontroller
@requestmapping(value = "/mybatis/author")
public class authorcontrollerv2 {
    @autowired
    private authorservicev2 authorservicev2;

    /**
     * 查询作者列表
     */
    @requestmapping(value = "getauthorlistv2", method = requestmethod.get)
    public map<string, object> getauthorlist() {
        list<author> authorlist = this.authorservicev2.findauthorlist();
        map<string, object> param = new hashmap<>();
        param.put("total", authorlist.size());
        param.put("rows", authorlist);
        return param;
    }

    /**
     * 查询单个作者信息
     */
    @requestmapping(value = "/getauthorv2/{authorid:\\d+}", method = requestmethod.get)
    public author getauthor(@pathvariable integer authorid) {
        author author = this.authorservicev2.findauthor(authorid);
        if (author == null) {
            throw new runtimeexception("查询错误");
        }
        return author;
    }

    /**
     * 新增
     */
    @requestmapping(value = "addv2", method = requestmethod.post)
    public void add(@requestbody jsonobject jsonobject) {
        string authorname = jsonobject.getstring("authorname");
        string penname = jsonobject.getstring("penname");

        try {
            this.authorservicev2.add(authorname, penname);
        } catch (exception e) {
            e.printstacktrace();
            throw new runtimeexception("新增错误");
        }
    }

    /**
     * 更新
     */
    @requestmapping(value = "/updatev2/{authorid:\\d+}", method = requestmethod.put)
    public void update(@pathvariable integer authorid, @requestbody jsonobject jsonobject) {
        author author = this.authorservicev2.findauthor(authorid);
        string authorname = jsonobject.getstring("authorname");
        string penname = jsonobject.getstring("penname");

        try {
            this.authorservicev2.update(authorname, penname, author.getauthorid());
        } catch (exception e) {
            e.printstacktrace();
            throw new runtimeexception("更新错误");
        }
    }

    /**
     * 删除
     */
    @requestmapping(value = "/deletev2/{authorid:\\d+}", method = requestmethod.delete)
    public void delete(@pathvariable integer authorid) {
        try {
            this.authorservicev2.delete(authorid);
        } catch (exception e) {
            throw new runtimeexception("删除错误");
        }
    }
}

10. 使用postman验证

10.1 验证新增

因为新增是post请求，因此这里我们使用下postman工具：

调用完接口，发现数据库新增数据成功。

然后用同样的方法新增下鲁迅的信息。

10.2 验证更新

调用更新接口将鲁迅的名字从周作人修改为周树人：

调用完接口，发现数据库更新数据成功。

10.3 验证获取列表

在浏览器访问http://localhost:8080/mybatis/author/getauthorlistv2，返回数据如下：

{
  "total": 2,
  "rows": [
    {
      "authorid": 1,
      "authorname": "王卫国",
      "penname": "路遥"
    },
    {
      "authorid": 2,
      "authorname": "周树人",
      "penname": "鲁迅"
    }
  ]
}

10.4 验证获取单个数据

在浏览器访问http://localhost:8080/mybatis/author/getauthorv2/1，返回如下数据：

{
  "authorid": 1,
  "authorname": "王卫国",
  "penname": "路遥"
}

10.5 验证删除

调用删除接口，将鲁迅的数据删除：

此时访问http://localhost:8080/mybatis/author/getauthorlistv2，返回数据只有1条了：

{
  "total": 1,
  "rows": [
    {
      "authorid": 1,
      "authorname": "王卫国",
      "penname": "路遥"
    }
  ]
}

11. 源码

源码地址：，欢迎下载。

12. 参考

spring boot 揭秘与实战（二） 数据存储篇 - mybatis整合

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