springboot2之结合mybatis增删改查解析

1. 场景描述

本节结合springboot2、springmvc、mybatis、swagger2等，搭建一个完整的增删改查项目，希望通过这个基础项目，能帮忙朋友快速上手springboot2项目。

2. 解决方案

2.1新建springboot项目

使用idea新建springboot项目（springboot项目快速搭建）

（1）new project

（2）gav设置

2.2 项目整体图及说明

2.2.1 整体图

2.2.2 说明

项目包含4大内容

（1）pom.xml

maven项目必备，用于定义项目、获取jar包、打包等。

（2）项目配置文件

有两个，一个是项目内配置文件；一个是用于mybatis-generate生成相关数据库操作文件。

（3）spcrudapplication

项目启动类，springboot项目必备。

（4）springmvc对应类。

包含controller、service、db等相关类。

2.3 详细说明

2.3.1 pom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 https://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>2.1.7.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.laowang</groupId>
    <artifactId>spcrud</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spcrud</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
     <!--1.web启动包 软件老王-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!--2. 数据库 软件老王-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.15</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
            <version>2.1.5.RELEASE</version>
        </dependency>

        <!--3. swagger 软件老王-->
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>2.7.0</version>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>2.7.0</version>
        </dependency>
        <!--4.mybatis 软件老王-->
        <!--mybatis-->
        <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.1.0</version>
    </dependency>

    </dependencies>

     <!--5.打包 软件老王-->
    <build>
        <resources>
            <resource>
                <directory>src/main/resources/</directory>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>

            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.5</version>
                <configuration>
                  <configurationFile>src/main/resources/generatorConfig.xml</configurationFile>
                    <verbose>true</verbose>
                    <overwrite>true</overwrite>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

说明：

包含5块内容

（1）web启动包 ；

（2）数据库 ；

（3）swagger；

（4）mybatis；

（5）打包；

2.3.2 资源文件

（1）application.properties

spring.datasource.url=jdbc:mysql://127.0.0.1:3306/ruanjianlaowang?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=root

说明： 数据库配置文件，连接、用户名、密码

（2）mybatis资源文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
    <classPathEntry
            location="E:\m2\repository\mysql\mysql-connector-java\5.1.46\mysql-connector-java-5.1.46.jar"/>
    <context id="DB2Tables" targetRuntime="MyBatis3">
        <!--<plugin type="org.mybatis.generator.plugins.ExamplePagePlugin"/>-->
        <!--<plugin type="org.mybatis.generator.plugins.SerializablePlugin"/>-->
        <commentGenerator>
            <!-- 是否去除自动生成的注释 true：是 ： false:否 -->
            <property name="suppressAllComments" value="true"/>
        </commentGenerator>

        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://127.0.0.1:3306/ruanjianlaowang"
                        userId="root"
                        password="root">
        </jdbcConnection>

        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <javaModelGenerator targetPackage="com.laowang.spcrud.db.entity" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>
        <sqlMapGenerator targetPackage="com.laowang.spcrud.db.mapper" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.laowang.spcrud.db.mapper" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>

        <table tableName="t_laowang" domainObjectName="TLaowang" enableInsert="true"
               enableDeleteByPrimaryKey="true"
               enableSelectByPrimaryKey="true"
               enableUpdateByPrimaryKey="true"
               enableCountByExample="false"
               enableDeleteByExample="false"
               enableSelectByExample="false"
               enableUpdateByExample="false">
            <property name="useActualColumnNames" value="false"/>
            <generatedKey column="id" sqlStatement="MYSQL" identity="true"/>
        </table>

    </context>
</generatorConfiguration>

说明：

包含几块内容：

（a）classPathEntry 标签定义的是mysql-connector的jar包地址

（b）jdbcConnection 数据库连接信息

（c）javaModelGenerator、sqlMapGenerator、javaClientGenerator定义的是生成文件存放的地址；

（d）table具体执行生成代码的tabel，增加几个标签，不生成example方法。

2.3.3 启动类

package com.laowang.spcrud;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import springfox.documentation.swagger2.annotations.EnableSwagger2;

@SpringBootApplication
@EnableSwagger2
@MapperScan("com.laowang.spcrud.db.mapper")
public class SpcrudApplication {

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

}

说明：

@SpringBootApplication所有springboot项目启动必备

@EnableSwagger2 启动swagger

@MapperScan加载mpper文件。

2.3.4 springmvc类

（1）TestController

package com.laowang.spcrud.controller;

import com.laowang.spcrud.db.entity.TLaowang;
import com.laowang.spcrud.service.TestService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestController {
    @Autowired
    private TestService testService;

    /**
     *  增加
     * @auther: 软件老王
     */
    @RequestMapping(value ="/save", method = RequestMethod.POST)
    @ResponseBody
    public  String save(TLaowang tLaowang) {
        testService.insertRecord(tLaowang);
        return "保存成功，i'm 软件老王！";
    }
    /**
     *  删除
     * @auther: 软件老王
     */
    @RequestMapping(value ="/delete", method = RequestMethod.POST)
    @ResponseBody
    public  String delete(int id) {
        testService.deleteByPrimaryKey(id);
        return "删除成功，i'm 软件老王！";
    }

    /**
     *  更新
     * @auther: 软件老王
     */
    @RequestMapping(value ="/update", method = RequestMethod.POST)
    @ResponseBody
    public  String update(TLaowang tLaowang) {
        testService.updateByPrimaryKeySelective(tLaowang);
        return "更新成功，i'm 软件老王！";
    }
    /**
     *  查询
     * @auther: 软件老王
     */
    @RequestMapping(value ="/select", method = RequestMethod.POST)
    @ResponseBody
    public  Object select(int id) {
        return testService.selectByPrimaryKey(id);
    }
}

ctroller类包含增删改查4个方法，使用了rest请求的方式。

（2）TestService

package com.laowang.spcrud.service;

import com.laowang.spcrud.db.entity.TLaowang;
import com.laowang.spcrud.db.mapper.TLaowangMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class TestService {
    @Autowired
    private TLaowangMapper tLaowangMapper;

    /**
     *  增加
     * @auther: 软件老王
     */
    public  void insertRecord(TLaowang tLaowang) {
        tLaowangMapper.insert(tLaowang);
    }

    /**
     *  删除
     * @auther: 软件老王
     */
    public  void deleteByPrimaryKey(int id) {
        tLaowangMapper.deleteByPrimaryKey(id);
    }
    /**
     *  更新
     * @auther: 软件老王
     */
    public  void updateByPrimaryKeySelective(TLaowang tLaowang) {
        tLaowangMapper.updateByPrimaryKeySelective(tLaowang);
    }

    /**
     *  查询
     * @auther: 软件老王
     */
    public  TLaowang selectByPrimaryKey(int id) {
        return tLaowangMapper.selectByPrimaryKey(id);
    }
}

TestService类，增删改查的服务类。

（3）实体类TLaowang

package com.laowang.spcrud.db.entity;

public class TLaowang {
    private Integer id;

    private String name;

    private String password;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name == null ? null : name.trim();
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password == null ? null : password.trim();
    }
}

操作实体类，包含三个字段：id、name、password

（4）mpper接口类TLaowangMapper

package com.laowang.spcrud.db.mapper;

import com.laowang.spcrud.db.entity.TLaowang;

public interface TLaowangMapper {
    int deleteByPrimaryKey(Integer id);

    int insert(TLaowang record);

    int insertSelective(TLaowang record);

    TLaowang selectByPrimaryKey(Integer id);

    int updateByPrimaryKeySelective(TLaowang record);

    int updateByPrimaryKey(TLaowang record);
}

（5）mapper接口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.laowang.spcrud.db.mapper.TLaowangMapper">
  <resultMap id="BaseResultMap" type="com.laowang.spcrud.db.entity.TLaowang">
    <id column="id" jdbcType="INTEGER" property="id" />
    <result column="name" jdbcType="VARCHAR" property="name" />
    <result column="password" jdbcType="VARCHAR" property="password" />
  </resultMap>
  <sql id="Base_Column_List">
    id, name, password
  </sql>
  <select id="selectByPrimaryKey" parameterType="java.lang.Integer" resultMap="BaseResultMap">
    select
    <include refid="Base_Column_List" />
    from t_laowang
    where id = #{id,jdbcType=INTEGER}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer">
    delete from t_laowang
    where id = #{id,jdbcType=INTEGER}
  </delete>
  <insert id="insert" parameterType="com.laowang.spcrud.db.entity.TLaowang">
    <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">
      SELECT LAST_INSERT_ID()
    </selectKey>
    insert into t_laowang (name, password)
    values (#{name,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR})
  </insert>
  <insert id="insertSelective" parameterType="com.laowang.spcrud.db.entity.TLaowang">
    <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">
      SELECT LAST_INSERT_ID()
    </selectKey>
    insert into t_laowang
    <trim prefix="(" suffix=")" suffixOverrides=",">
      <if test="name != null">
        name,
      </if>
      <if test="password != null">
        password,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides=",">
      <if test="name != null">
        #{name,jdbcType=VARCHAR},
      </if>
      <if test="password != null">
        #{password,jdbcType=VARCHAR},
      </if>
    </trim>
  </insert>
  <update id="updateByPrimaryKeySelective" parameterType="com.laowang.spcrud.db.entity.TLaowang">
    update t_laowang
    <set>
      <if test="name != null">
        name = #{name,jdbcType=VARCHAR},
      </if>
      <if test="password != null">
        password = #{password,jdbcType=VARCHAR},
      </if>
    </set>
    where id = #{id,jdbcType=INTEGER}
  </update>
  <update id="updateByPrimaryKey" parameterType="com.laowang.spcrud.db.entity.TLaowang">
    update t_laowang
    set name = #{name,jdbcType=VARCHAR},
      password = #{password,jdbcType=VARCHAR}
    where id = #{id,jdbcType=INTEGER}
  </update>
</mapper>

4与5在一起，这里使用了mybatis自动生成的增删改查方法，未做扩展，真实项目中除了这几个外，肯定还会做些扩展，比如根据name查询等。

2.4 数据库建表语句

CREATE TABLE `t_laowang` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(50) DEFAULT NULL,
  `password` varchar(50) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

2.5 swagger效果

http://localhost:8080/swagger-ui.html

完整的代码，完整的注释，希望对你有帮助。

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