基于SpringBoot + Mybatis实现SpringMVC Web项目

1、pom.xml文件

<?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>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.0</version>
    </parent>

    <groupId>com.coffee</groupId>
    <artifactId>webmvc-demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <mybatis.verison>2.2.2</mybatis.verison>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-commons</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>


        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>${mybatis.verison}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2、主启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

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

3、实体类

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.io.Serializable;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class People implements Serializable {
    private static final long serialVersionUID = 620950479129453625L;

    private Integer id;

    private String username;

    private String gender;

    private String address;
}

4、dao层

import com.coffee.webmvc.samples.entity.People;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.springframework.data.domain.Pageable;

import java.util.List;

@Mapper
public interface PeopleDao {

    /**
     * 通过ID查询单条数据
     *
     * @param id 主键
     * @return 实例对象
     */
    People queryById(Integer id);

    /**
     * 查询指定行数据
     *
     * @param people   查询条件
     * @param pageable 分页对象
     * @return 对象列表
     */
    List<People> queryAllByLimit(People people, @Param("pageable") Pageable pageable);

    /**
     * 统计总行数
     *
     * @param people 查询条件
     * @return 总行数
     */
    long count(People people);

    /**
     * 新增数据
     *
     * @param people 实例对象
     * @return 影响行数
     */
    int insert(People people);

    /**
     * 批量新增数据（MyBatis原生foreach方法）
     *
     * @param entities List<People> 实例对象列表
     * @return 影响行数
     */
    int insertBatch(@Param("entities") List<People> entities);

    /**
     * 批量新增或按主键更新数据（MyBatis原生foreach方法）
     *
     * @param entities List<People> 实例对象列表
     * @return 影响行数
     * @throws org.springframework.jdbc.BadSqlGrammarException 入参是空List的时候会抛SQL语句错误的异常，请自行校验入参
     */
    int insertOrUpdateBatch(@Param("entities") List<People> entities);

    /**
     * 修改数据
     *
     * @param people 实例对象
     * @return 影响行数
     */
    int update(People people);

    /**
     * 通过主键删除数据
     *
     * @param id 主键
     * @return 影响行数
     */
    int deleteById(Integer id);

}

5、service层

package com.coffee.webmvc.samples.service;

import com.coffee.webmvc.samples.entity.People;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;

public interface PeopleService {

    /**
     * 通过ID查询单条数据
     *
     * @param id 主键
     * @return 实例对象
     */
    People queryById(Integer id);

    /**
     * 分页查询
     *
     * @param people      筛选条件
     * @param pageRequest 分页对象
     * @return 查询结果
     */
    Page<People> queryByPage(People people, PageRequest pageRequest);

    /**
     * 新增数据
     *
     * @param people 实例对象
     * @return 实例对象
     */
    People insert(People people);

    /**
     * 修改数据
     *
     * @param people 实例对象
     * @return 实例对象
     */
    People update(People people);

    /**
     * 通过主键删除数据
     *
     * @param id 主键
     * @return 是否成功
     */
    boolean deleteById(Integer id);
}

6、service实现类

import com.coffee.webmvc.samples.entity.People;
import com.coffee.webmvc.samples.dao.PeopleDao;
import com.coffee.webmvc.samples.service.PeopleService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageImpl;
import org.springframework.data.domain.PageRequest;

@Service("peopleService")
public class PeopleServiceImpl implements PeopleService {

    @Autowired
    private PeopleDao peopleDao;

    /**
     * 通过ID查询单条数据
     *
     * @param id 主键
     * @return 实例对象
     */
    @Override
    public People queryById(Integer id) {
        return this.peopleDao.queryById(id);
    }

    /**
     * 分页查询
     *
     * @param people      筛选条件
     * @param pageRequest 分页对象
     * @return 查询结果
     */
    @Override
    public Page<People> queryByPage(People people, PageRequest pageRequest) {
        long total = this.peopleDao.count(people);
        return new PageImpl<>(this.peopleDao.queryAllByLimit(people, pageRequest), pageRequest, total);
    }

    /**
     * 新增数据
     *
     * @param people 实例对象
     * @return 实例对象
     */
    @Override
    public People insert(People people) {
        this.peopleDao.insert(people);
        return people;
    }

    /**
     * 修改数据
     *
     * @param people 实例对象
     * @return 实例对象
     */
    @Override
    public People update(People people) {
        this.peopleDao.update(people);
        return this.queryById(people.getId());
    }

    /**
     * 通过主键删除数据
     *
     * @param id 主键
     * @return 是否成功
     */
    @Override
    public boolean deleteById(Integer id) {
        return this.peopleDao.deleteById(id) > 0;
    }
}

7、controller层

import com.coffee.webmvc.samples.entity.People;
import com.coffee.webmvc.samples.service.PeopleService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("people")
public class PeopleController {
    /**
     * 服务对象
     */
    @Autowired
    private PeopleService peopleService;

    /**
     * 分页查询
     *
     * @param people      筛选条件
     * @param pageRequest 分页对象
     * @return 查询结果
     */
    @GetMapping("/queryByPage")
    public ResponseEntity<Page<People>> queryByPage(People people, PageRequest pageRequest) {
        return ResponseEntity.ok(this.peopleService.queryByPage(people, pageRequest));
    }

    /**
     * 通过主键查询单条数据
     *
     * @param id 主键
     * @return 单条数据
     */
    @GetMapping("{id}")
    public ResponseEntity<People> queryById(@PathVariable("id") Integer id) {
        return ResponseEntity.ok(this.peopleService.queryById(id));
    }

    /**
     * 新增数据
     *
     * @param people 实体
     * @return 新增结果
     */
    @PostMapping
    public ResponseEntity<People> add(People people) {
        return ResponseEntity.ok(this.peopleService.insert(people));
    }

    /**
     * 编辑数据
     *
     * @param people 实体
     * @return 编辑结果
     */
    @PutMapping({"{id}"})
    public ResponseEntity<People> edit(@PathVariable("id") People people) {
        return ResponseEntity.ok(this.peopleService.update(people));
    }

    /**
     * 删除数据
     *
     * @param id 主键
     * @return 删除是否成功
     */
    @DeleteMapping({"{id}"})
    public ResponseEntity<Boolean> deleteById(@PathVariable("id") Integer id) {
        return ResponseEntity.ok(this.peopleService.deleteById(id));
    }

}

8、mapper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.coffee.webmvc.samples.dao.PeopleDao">

    <resultMap type="com.coffee.webmvc.samples.entity.People" id="PeopleMap">
        <result property="id" column="id" jdbcType="INTEGER"/>
        <result property="username" column="username" jdbcType="VARCHAR"/>
        <result property="gender" column="gender" jdbcType="VARCHAR"/>
        <result property="address" column="address" jdbcType="VARCHAR"/>
    </resultMap>

    <!--查询单个-->
    <select id="queryById" resultMap="PeopleMap">
        select id,
               username,
               gender,
               address
        from people
        where id = #{id}
    </select>

    <!--查询指定行数据-->
    <select id="queryAllByLimit" resultMap="PeopleMap">
        select
        id, username, gender, address
        from people
        <where>
            <if test="id != null">
                and id = #{id}
            </if>
            <if test="username != null and username != ''">
                and username = #{username}
            </if>
            <if test="gender != null and gender != ''">
                and gender = #{gender}
            </if>
            <if test="address != null and address != ''">
                and address = #{address}
            </if>
        </where>
        limit #{pageable.offset}, #{pageable.pageSize}
    </select>

    <!--统计总行数-->
    <select id="count" resultType="java.lang.Long">
        select count(1)
        from people
        <where>
            <if test="id != null">
                and id = #{id}
            </if>
            <if test="username != null and username != ''">
                and username = #{username}
            </if>
            <if test="gender != null and gender != ''">
                and gender = #{gender}
            </if>
            <if test="address != null and address != ''">
                and address = #{address}
            </if>
        </where>
    </select>

    <!--新增所有列-->
    <insert id="insert" keyProperty="id" useGeneratedKeys="true">
        insert into people(username, gender, address)
        values (#{username}, #{gender}, #{address})
    </insert>

    <insert id="insertBatch" keyProperty="id" useGeneratedKeys="true">
        insert into people(username, gender, address)
        values
        <foreach collection="entities" item="entity" separator=",">
            (#{entity.username}, #{entity.gender}, #{entity.address})
        </foreach>
    </insert>

    <insert id="insertOrUpdateBatch" keyProperty="id" useGeneratedKeys="true">
        insert into people(username, gender, address)
        values
        <foreach collection="entities" item="entity" separator=",">
            (#{entity.username}, #{entity.gender}, #{entity.address})
        </foreach>
        on duplicate key update
        username = values(username),
        gender = values(gender),
        address = values(address)
    </insert>

    <!--通过主键修改数据-->
    <update id="update">
        update people
        <set>
            <if test="username != null and username != ''">
                username = #{username},
            </if>
            <if test="gender != null and gender != ''">
                gender = #{gender},
            </if>
            <if test="address != null and address != ''">
                address = #{address},
            </if>
        </set>
        where id = #{id}
    </update>

    <!--通过主键删除-->
    <delete id="deleteById">
        delete
        from people
        where id = #{id}
    </delete>
</mapper>

9、application.properties

server.port=8080

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.url=jdbc:mysql://localhost:3306/demo?characterEncoding=UTF-8&useSSL=false&serverTimezone=UTC&allowPublicKeyRetrieval=true

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

至此，整合数据库实现增删改查的一个简单SpringMVC Web项目就搭建完成。详细的项目目录结构如下图：

备注：以上大多数代码可以利用EasyCode结合数据库自动生成。