Spring boot整合mybatis实现数据的CRUD

我不是女神ヾ 2022-06-13 19:58 247阅读 0赞

# Spring boot整合mybatis实现数据的CRUD #

本文主要参考：

https://spring.io/guides/gs/rest-service/  这个是如何搭建Spring boot

本文略过如何搭建spring boot，默认已经搭建好spring boot了，如果想要搭建spring boot可以参考上边的文章。

好，下面上货。

首先看一下目录结构：

![Center][]

1、添加maven依赖。

<dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>1.3.0</version>
            </dependency>

2、在classpath:mybatis文件夹下添加mybatis-conf.xml文件

<?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="String" type="java.lang.String"/>
            <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>

3、添加实体类Student:

package com.xueyou.demo.pojo;
    
    import com.fasterxml.jackson.annotation.JsonFormat;
    
    import java.util.Date;
    
    /**
     * Created by wuxueyou on 2017/5/26.
     */
    public class Student {
        private int id;
        private String name;
    
        private int age;
        private String attr;
    
        private Date createtime;
        private Date updatetime;
    
    
        public Student() {
        }
    
        public Student(int id) {
            this.id = id;
        }
    
        public Student(int id, String name) {
            this.id = id;
            this.name = name;
        }
    
        public Student(int id, String name, int age, String attr) {
            this.id = id;
            this.name = name;
            this.age = age;
            this.attr = attr;
        }
    
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
    
        public int getAge() {
            return age;
        }
    
        public void setAge(int age) {
            this.age = age;
        }
    
        public String getAttr() {
            return attr;
        }
    
        public void setAttr(String attr) {
            this.attr = attr;
        }
    
        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
        public Date getCreatetime() {
            return createtime;
        }
    
        public void setCreatetime(Date createtime) {
            this.createtime = createtime;
        }
    
        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
        public Date getUpdatetime() {
            return updatetime;
        }
    
        public void setUpdatetime(Date updatetime) {
            this.updatetime = updatetime;
        }
    }

4、添加DAO接口

package com.xueyou.demo.dao;
    
    import com.xueyou.demo.pojo.Student;
    
    import java.util.Date;
    import java.util.HashMap;
    import java.util.List;
    
    /**
     * Created by wuxueyou on 2017/6/15.
     */
    public interface StudentDao {
        List<Student> getAll();
    
        Student getById(int id);
    
        List<Student> getByNameLike(String name);
    
        Student getByIdAndName(Student student);
    
        Student getByIdAndNameWithParamMap(HashMap<String,Object> params);
    
        List<Student> getByCreateTime(Date date);
    
        int insertStudent(Student student);
    
        int deleteById(Student student);
    }

5、添加studentmapper.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.xueyou.demo.dao.StudentDao">
    
        <sql id="allField">
        id, `name`, age, memo AS attr, createtime, updatetime
        </sql>
    
        <select id="getAll" resultType="com.xueyou.demo.pojo.Student">
            select
            <include refid="allField"/>
            from student
        </select>
    
        <select id="getById" resultType="com.xueyou.demo.pojo.Student">
            SELECT
            <include refid="allField"/>
            from student WHERE id = #{id}
        </select>
    
        <select id="getByNameLike" resultType="com.xueyou.demo.pojo.Student">
            SELECT
            <include refid="allField"/>
            from student WHERE name LIKE CONCAT('%',#{name},'%')
        </select>
    
        <select id="getByIdAndName" resultType="com.xueyou.demo.pojo.Student" parameterType="com.xueyou.demo.pojo.Student">
            SELECT
            <include refid="allField"/>
            from student WHERE id = #{id} AND name = #{name}
        </select>
    
        <select id="getByIdAndNameWithParamMap" resultType="com.xueyou.demo.pojo.Student" parameterType="HashMap">
            SELECT
            <include refid="allField"/>
            from student WHERE id = #{id} AND name = #{name}
        </select>
    
        <select id="getByCreateTime" resultType="com.xueyou.demo.pojo.Student">
            SELECT
            <include refid="allField"/>
            from student where createtime >= #{date}
        </select>
    
        <insert id="insertStudent" parameterType="com.xueyou.demo.pojo.Student">
            insert INTO student(id, `name`, age, memo)
            VALUES (#{id},#{name},#{age},#{memo})
        </insert>
    
        <delete id="deleteById">
            DELETE FROM student where id = #{id}
        </delete>
    </mapper>

6、在controller层进行处理：

package com.xueyou.demo.controller;
    
    import com.xueyou.demo.dao.StudentDao;
    import com.xueyou.demo.pojo.Student;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import java.text.SimpleDateFormat;
    import java.util.Date;
    import java.util.HashMap;
    import java.util.List;
    
    /**
     * Created by wuxueyou on 2017/6/15.
     */
    @RestController
    @RequestMapping("/mybatis")
    public class mybatisTestController {
        @Autowired
        public StudentDao studentDao;
    
        @RequestMapping("/getAll")
        public List<Student> getAll() {
            List<Student> studentList = studentDao.getAll();
            return studentList;
        }
    
        @RequestMapping("/getById")
        public Student getById(int id) {
            return studentDao.getById(id);
        }
    
        @RequestMapping("/getByNameLike")
        public List<Student> getByNameLike(String name) {
            return studentDao.getByNameLike(name);
        }
    
        @RequestMapping("/getByIdAndName")
        public Student getByIdAndName(int id, String name) {
            return studentDao.getByIdAndName(new Student(id, name));
        }
    
        @RequestMapping("/getByIdAndNameWithParamMap")
        public Student getByIdAndNameWithParamMap(int id, String name) {
            HashMap<String, Object> param = new HashMap<>();
            param.put("id", id);
            param.put("name", name);
            return studentDao.getByIdAndNameWithParamMap(param);
        }
    
        @RequestMapping("/getByCreatetime")
        public List<Student> getByCreatetime(String dateStr) throws Exception {
            Date date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(dateStr);
            return studentDao.getByCreateTime(date);
        }
    
        @RequestMapping("/insertStudent")
        public int insertStudent(int id, String name, int age, String memo) {
            return studentDao.insertStudent(new Student(id, name, age, memo));
        }
    
        @RequestMapping("/deleteById")
        public int deleteById(int id) {
            return studentDao.deleteById(new Student(id));
        }
    }

7、这里需要注意的是在springboot启动的时候需要添加mapperscan注解

@MapperScan(basePackages = {"com.xueyou.demo.dao"})

否则会出现找不到接口的实现类的问题。

测试数据：

![Center 1][]

由于请求很多，这里不一一列出了。update和delete的返回值是sql执行后受影响的行数。如果返回0，那么就意味着更新或者删除失败。

后记：2018年3月23日

当前如果更新了新版本的mybatis starter，那么需要再application.properties里面配置好xml的路径

#mybatis mybatis.mapper-locations=classpath:/mybatis/mapper/*.xml

否则，会出现找不到dao的实现类的异常。

[Center]: /images/20220614/2b13d407069544629fb2576822f9a21b.png
[Center 1]: /images/20220614/95eb05c219e146d1bc6e731a9274c34b.png