Spring Boot项目开发（一）——通过mybatis-generator自动生成基础代码

一、创建项目

通过IDEA的Initializr创建项目，详情参见：Spring Boot入门

 二、添加项目依赖

添加Mybatis、Mysql、mybatis-generator（用于生成项目基础代码）依赖

<?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>2.2.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.learn</groupId>
    <artifactId>mall</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mall</name>
    <description>mall project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <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>
        <!--添加mybatis依赖-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>
        <!--添加MySQL依赖-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <!--添加mybatis逆向工程插件-->
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.7</version>
                <configuration>
                    <verbose>true</verbose>
                    <overwrite>true</overwrite>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

 三、编写generatorConfig.xml配置文件

编写generatorConfig.xml配置文件，将文件放在resources目录下，配置文件官网地址：http://mybatis.org/generator/configreference/xmlconfig.html

<?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>
    <!-- 指定数据连接驱动jar地址 -->
    <classPathEntry location="D:softwareapache-maven-3.5.2
epository4mysqlmysql-connector-java8.0.18mysql-connector-java-8.0.18.jar"/>
    <!-- 一个数据库一个context -->
    <context id="MySQLTables" targetRuntime="MyBatis3">
        <!-- 注释 -->
        <commentGenerator>
            <!-- 是否取消注释 -->
            <property name="suppressAllComments" value="true"/>
            <!-- 是否生成注释代时间戳-->
            <property name="suppressDate" value="true"/>
        </commentGenerator>
        <!-- jdbc连接 -->
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver"
                        connectionURL="jdbc:mysql://192.168.211.128:3316/mall?serverTimeZone=UTC&amp;
                        useUnicode=true&amp;characterEncoding=utf-8&amp;useSSL=true"
                        userId="root"
                        password="123456"/>
        <!-- 类型转换 -->
        <javaTypeResolver>
            <!-- 是否使用bigDecimal， false可自动转化以下类型（Long, Integer, Short, etc.） -->
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <!-- 生成实体类地址 -->
        <javaModelGenerator targetPackage="com.learn.mall.model.pojo" targetProject="src/main/java">
            <!-- 是否在当前路径下新加一层schema,eg：fase路径com.oop.eksp.user.model， true:com.oop.eksp.user.model.[schemaName] -->
            <property name="enableSubPackages" value="true"/>
            <!-- 是否针对string类型的字段在set的时候进行trim调用 -->
            <property name="trimStrings" value="true"/>
            <!--建立的model对象是否不可改变，即生成的Model对象不会有setter方法，只有构造方法-->
            <property name="immutable" value="false"/>
        </javaModelGenerator>
        <!-- 生成mapper映射文件存放位置即xml文件 -->
        <sqlMapGenerator targetPackage="mappers" targetProject="src/main/resources">
            <!-- 是否在当前路径下新加一层schema,eg：fase路径com.oop.eksp.user.model， true:com.oop.eksp.user.model.[schemaName] -->
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>
        <!-- 生成dao类存放位置 -->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.learn.mall.model.dao" targetProject="src/main/java">
            <property name="enableSubPackages" value="false"/>
        </javaClientGenerator>
        <!-- 配置表信息 -->
        <!--tableName为对应的数据库表 domainObjectName是要生成的实体类 enable*ByExample
                是否生成 example类   -->
        <table tableName="mall_cart"
               domainObjectName="Cart" enableCountByExample="false"
               enableDeleteByExample="false" enableSelectByExample="false"
               enableUpdateByExample="false" selectByExampleQueryId="false">
        </table>
        <table tableName="mall_category"
               domainObjectName="Category" enableCountByExample="false"
               enableDeleteByExample="false" enableSelectByExample="false"
               enableUpdateByExample="false" selectByExampleQueryId="false">
        </table>
        <table tableName="mall_order"
               domainObjectName="Order" enableCountByExample="false"
               enableDeleteByExample="false" enableSelectByExample="false"
               enableUpdateByExample="false" selectByExampleQueryId="false">
        </table>
        <table tableName="mall_order_item"
               domainObjectName="OrderItem" enableCountByExample="false"
               enableDeleteByExample="false" enableSelectByExample="false"
               enableUpdateByExample="false" selectByExampleQueryId="false">
        </table>
        <table tableName="mall_product"
               domainObjectName="Product" enableCountByExample="false"
               enableDeleteByExample="false" enableSelectByExample="false"
               enableUpdateByExample="false" selectByExampleQueryId="false">
        </table>
        <table tableName="mall_user"
               domainObjectName="User" enableCountByExample="false"
               enableDeleteByExample="false" enableSelectByExample="false"
               enableUpdateByExample="false" selectByExampleQueryId="false">
        </table>
    </context>
</generatorConfiguration>

 四、启动mybatis-generator生成基础代码

打开IDEA的Maven Projects窗口，点击mybatis-generator启动插件，运行完成后即可生成基础代码

 注意：代码生成之后需要给所有的Mapper文件加上@Repository注解，否则Service注入时会报错

package com.learn.mall.model.dao;

import com.learn.mall.model.pojo.Cart;
import org.springframework.stereotype.Repository;

@Repository
public interface CartMapper {
    int deleteByPrimaryKey(Integer id);

    int insert(Cart record);

    int insertSelective(Cart record);

    Cart selectByPrimaryKey(Integer id);

    int updateByPrimaryKeySelective(Cart record);

    int updateByPrimaryKey(Cart record);
}

 五、编写测试demo

1、在application.properties配置文件中配置数据库信息

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.url=jdbc:mysql://192.168.211.128:3316
  /mall?serverTimeZone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
mybatis.mapper-locations=classpath:mappers/*.xml

2、编写Service层接口

package com.learn.mall.service;

import com.learn.mall.model.pojo.User;

public interface UserService {
    User getUser();
}

 3、编写ServiceImpl

package com.learn.mall.service.impl;

import com.learn.mall.model.dao.UserMapper;
import com.learn.mall.model.pojo.User;
import com.learn.mall.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    UserMapper userMapper;
    @Override
    public User getUser() {
        return userMapper.selectByPrimaryKey(1);
    }
}

 4、编写Controller

package com.learn.mall.controller;

import com.learn.mall.model.pojo.User;
import com.learn.mall.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class UserController {
    @Autowired
    UserService userService;

    @GetMapping("/test")
    @ResponseBody
    public User getUser(){
        return  userService.getUser();
    }
}

5、浏览器请求测试