前言

mybatis自带代码生成插件，我们来试试如何使用

创建空项目

我们通过IDEA的Spring Intializr先创建一个sbm-generator的项目

1.png

目录结构

2.png

标红部分是代码生成器自动生成的代码，如何生成的请往下看

添加依赖

pom.xml引入代码生成依赖：

<?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 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>2.1.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>


    <groupId>com.mrcoder</groupId>
    <artifactId>sbm-generator</artifactId>
    <version>0.0.1</version>
    <name>sbm-generator</name>
    <description>Demo project for Spring Boot</description>

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

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

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

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

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.0</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.3</version>
        </dependency>

    </dependencies>

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


            <plugin>
                <!--Mybatis-generator插件,用于自动生成Mapper和POJO-->
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.2</version>
                <configuration>
                    <!--配置文件的位置-->
                    <configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>
                    <verbose>true</verbose>
                    <overwrite>true</overwrite>
                </configuration>
                <executions>
                    <execution>
                        <id>Generate MyBatis Artifacts</id>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                    </execution>
                </executions>
                <dependencies>
                    <dependency>
                        <groupId>org.mybatis.generator</groupId>
                        <artifactId>mybatis-generator-core</artifactId>
                        <version>1.3.2</version>
                    </dependency>
                </dependencies>
            </plugin>


        </plugins>
    </build>

</project>

添加配置

application.yml:

spring:
  datasource:
    url: jdbc:mysql://192.168.145.131:3306/test?useUnicode=true&characterEncoding=UTF-8&useSSL=false&autoReconnect=true&failOverReadOnly=false&serverTimezone=GMT%2B8
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver



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


#pagehelper分页插件
pagehelper:
  helperDialect: mysql
  reasonable: true
  supportMethodsArguments: true
  params: count=countSql

建库

建立test库，建表:

CREATE TABLE `person` (
  `id` int(11) NOT NULL,
  `name` varchar(255) DEFAULT NULL,
  `age` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

INSERT INTO `person` VALUES ('1', '1', '1');
INSERT INTO `person` VALUES ('2', '2', '2');
INSERT INTO `person` VALUES ('3', '3', '3');
INSERT INTO `person` VALUES ('4', '4', '4');
INSERT INTO `person` VALUES ('5', '5', '5');
INSERT INTO `person` VALUES ('6', '6', '6');
INSERT INTO `person` VALUES ('7', '7', '7');
INSERT INTO `person` VALUES ('8', '8', '8');
INSERT INTO `person` VALUES ('9', '9', '9');
INSERT INTO `person` VALUES ('10', '10', '10');
INSERT INTO `person` VALUES ('11', '11', '11');

mybatis-generator的使用

在pom.xml我们配置了代码生成器配置的目录即

3.png

接下来我们就在对应的
/src/main/resources/generator/目录下创建此文件(generator文件夹请手动创建) generatorConfig.xml：

<?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>

    <!-- 本地数据库驱动程序jar包的全路径 -->
    <classPathEntry location="D:\MaveRepository\mysql\mysql-connector-java\8.0.15\mysql-connector-java-8.0.15.jar"/>

    <context id="context" targetRuntime="MyBatis3">

        <!-- optional，旨在创建class时，对注释进行控制 -->
        <commentGenerator>
            <property name="suppressAllComments" value="true"/>
            <property name="suppressDate" value="true"/>
        </commentGenerator>

        <!-- 数据库的相关配置 -->
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver" connectionURL="jdbc:mysql://192.168.145.131:3306/test"
                        userId="root" password="123456"/>

        <!-- 非必需，类型处理器，在数据库类型和java类型之间的转换控制-->
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>

        <!-- Model实体类生成的位置 -->
        <javaModelGenerator targetPackage="com.mrcoder.sbmgenerator.entity" targetProject="src/main/java">
            <!-- 是否对model添加 构造函数 -->
            <property name="constructorBased" value="false"/>
            <!-- 是否允许子包，即targetPackage.schemaName.tableName -->
            <property name="enableSubPackages" 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"/>
            <!-- 给Model添加一个父类 -->
            <!--<property name="rootClass" value="com.foo.louis.Hello"/>-->
            <!-- 是否对类CHAR类型的列的数据进行trim操作 -->
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>

        <!-- *Mapper.xml 文件的位置 -->
        <sqlMapGenerator targetPackage="mapper" targetProject="src/main/resources">
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>

        <!-- Mapper 接口文件的位置 -->
        <javaClientGenerator targetPackage="com.mrcoder.sbmgenerator.mapper" targetProject="src/main/java"
                             type="XMLMAPPER">
            <property name="enableSubPackages" value="true"/>
            <!--
                    定义Maper.java 源代码中的ByExample() 方法的可视性，可选的值有：
                    public;
                    private;
                    protected;
                    default
                    注意：如果 targetRuntime="MyBatis3",此参数被忽略
             -->
            <property name="exampleMethodVisibility" value=""/>
            <!--方法名计数器Important note: this property is ignored if the target runtime is MyBatis3.-->
            <property name="methodNameCalculator" value=""/>
            <!--为生成的接口添加父接口-->
            <property name="rootInterface" value=""/>
        </javaClientGenerator>

        <!-- 相关表的配置 -->
        <table tableName="person" enableCountByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false"
               enableUpdateByExample="false"/>
    </context>
</generatorConfiguration>

相关配置的含义在代码中均有注释，请根据实际情况修改。

配置完成后，我们可以运行代码生成器mybatis-generator了，直接在IDEA右侧双击mybatis-generator：generate即可

4.png

运行成功会生成entity、mapper目录以及resources下的mapper目录。（参照上图目录结构）

完善

想要项目真正跑起来我们还得完善controller和service
我们在项目下右键新增controller和service的package，
service下再新增implpackage，

service/PersonService.java：

package com.mrcoder.sbmgenerator.service;
import com.mrcoder.sbmgenerator.entity.Person;
import java.util.List;

public interface PersonService {
    int addPerson(Person person);
    List<Person> findAllPerson(int pageNum, int pageSize);
}

service/impl/PersonServiceImpl.java:

package com.mrcoder.sbmgenerator.service.impl;

import com.github.pagehelper.PageHelper;
import com.mrcoder.sbmgenerator.entity.Person;
import com.mrcoder.sbmgenerator.mapper.PersonMapper;
import com.mrcoder.sbmgenerator.service.PersonService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service(value = "personService")
public class PersonServiceImpl implements PersonService {
    @Autowired
    private PersonMapper personMapper;//这里会报错，但是并不会影响

    @Override
    public int addPerson(Person person) {
        return personMapper.insert(person);
    }

    /*
     * 这个方法中用到了我们开头配置依赖的分页插件pagehelper
     * pageNum 开始页数
     * pageSize 每页显示的数据条数
     * */
    @Override
    public List<Person> findAllPerson(int pageNum, int pageSize) {
        //将参数传给这个方法就可以实现物理分页了，非常简单。
        PageHelper.startPage(pageNum, pageSize);
        return personMapper.selectAllPerson();
    }

}

mapper/PersonMapper.java:

package com.mrcoder.sbmgenerator.mapper;

import com.mrcoder.sbmgenerator.entity.Person;

import java.util.List;

public interface PersonMapper {
    int insert(Person record);

    int insertSelective(Person record);

     //selectAllPerson是自己新增的查询方法
    List<Person> selectAllPerson();

}

entity/Person.java:

package com.mrcoder.sbmgenerator.entity;

public class Person {
    private Integer id;

    private String name;

    private Integer age;

    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 Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}

controller/PersonController.java:

package com.mrcoder.sbmgenerator.controller;


import com.mrcoder.sbmgenerator.entity.Person;
import com.mrcoder.sbmgenerator.service.PersonService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class PersonController {
    @Autowired
    private PersonService personService;

    @ResponseBody
    @RequestMapping(value = "/all/{pageNum}/{pageSize}", produces = {"application/json;charset=UTF-8"})
    public Object findAllPerson(@PathVariable("pageNum") int pageNum, @PathVariable("pageSize") int pageSize){
        return personService.findAllPerson(pageNum,pageSize);
    }

}

运行

运行项目，访问

5.png

项目地址

https://github.com/MrCoderStack/SpringBootDemo/tree/master/sbm-generator

https://gitee.com/MrCoderStack/SpringBootDemo/tree/master/sbm-generator

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