MyBatis Generator自动生成

原文地址：https://blog.csdn.net/weixin_42476498/article/details/100511477

1.先在项目resources下创建并编写generatorConfig.xml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>


    
    <context id="mysqlgenerator" targetRuntime="MyBatis3">
        <plugin type="org.mybatis.generator.plugins.EqualsHashCodePlugin">plugin>
        <plugin type="org.mybatis.generator.plugins.SerializablePlugin">plugin>
        <plugin type="org.mybatis.generator.plugins.ToStringPlugin">plugin>
        <plugin type="com.itfsw.mybatis.generator.plugins.ExampleEnhancedPlugin"/>
        <plugin type="com.itfsw.mybatis.generator.plugins.ModelColumnPlugin"/>
        <plugin type="com.itfsw.mybatis.generator.plugins.ExampleTargetPlugin">
            <property name="targetPackage" value="com.zxd.testforteaching.example"/>
        plugin>
        <plugin type="com.itfsw.mybatis.generator.plugins.SelectOneByExamplePlugin"/>
        <plugin type="com.itfsw.mybatis.generator.plugins.LogicalDeletePlugin">
            
            
            <property name="logicalDeleteColumn" value="deleted"/>
            
            <property name="logicalDeleteValue" value="1"/>
            
            <property name="logicalUnDeleteValue" value="0"/>
        plugin>
        <plugin type="com.itfsw.mybatis.generator.plugins.OptimisticLockerPlugin"/>
        
        <plugin type="org.mybatis.generator.plugins.UnmergeableXmlMappersPlugin" />
        <commentGenerator>
            
            
            <property name="suppressDate" value="true"/>
            
            <property name="suppressAllComments" value="true"/>
        commentGenerator>
        
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver"
                        connectionURL="jdbc:mysql://127.0.0.1:3306/zxdtestmysql?nullCatalogMeansCurrent=true&serverTimezone=UTC"
                        userId="root"
                        password="root">
            <property name="useInformationSchema" value="true"/>
        jdbcConnection>
        
        <javaModelGenerator targetPackage="com.zxd.testforteaching.model"
                            targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
            <property name="trimStrings" value="true"/>
            <property name="constructorBased" value="false"/>
        javaModelGenerator>
        
        <sqlMapGenerator targetPackage="com.zxd.testforteaching.mapper"
                         targetProject="src/main/resources">
            <property name="enableSubPackages" value="true"/>
        sqlMapGenerator>
        
        <javaClientGenerator type="XMLMAPPER"
                             targetPackage="com.zxd.testforteaching.dao"
                             targetProject="src/main/java">
        javaClientGenerator>
        
        <table tableName="course" domainObjectName="Course">
        
        
        
        
        
            <generatedKey column="c_id" sqlStatement="MySql" identity="true"/>
        table>
    context>
generatorConfiguration>

2.设置pom.xml

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>4.0.0modelVersion>
    <parent>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-parentartifactId>
        <version>2.1.7.RELEASEversion>
        <relativePath/> 
    parent>
    <groupId>com.zxdgroupId>
    <artifactId>testforteachingartifactId>
    <version>0.0.1-SNAPSHOTversion>
    <name>testforteachingname>
    <description>Demo project for Spring Bootdescription>
    <properties>
        <java.version>1.8java.version>
    properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-webartifactId>
        dependency>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-testartifactId>
            <scope>testscope>
        dependency>
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <scope>runtimescope>
        dependency>
        <dependency>
            <groupId>org.mybatis.spring.bootgroupId>
            <artifactId>mybatis-spring-boot-starterartifactId>
            <version>1.3.2version>
        dependency>
    dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-maven-pluginartifactId>
            plugin>
            
            <plugin>
                <groupId>org.mybatis.generatorgroupId>
                <artifactId>mybatis-generator-maven-pluginartifactId>
                <version>1.3.7version>
                <configuration>
                    <configurationFile>${basedir}/src/main/resources/generatorConfig.xmlconfigurationFile>
                    <verbose>trueverbose>
                    
                    <overwrite>trueoverwrite>
                configuration>
                <dependencies>
                    
                    <dependency>
                        <groupId>mysqlgroupId>
                        <artifactId>mysql-connector-javaartifactId>
                        <version>8.0.13version>
                    dependency>
                    
                    <dependency>
                        <groupId>com.itfswgroupId>
                        <artifactId>mybatis-generator-pluginartifactId>
                        <version>1.2.10version>
                    dependency>
                    





                dependencies>
            plugin>
        plugins>
    build>

project>

3.项目根目录下执行 mvn mybatis-generator:generate
正确无误执行完，就是在你设定的位置生成mybatis的各文件。
ps:每次generate都会覆盖原来的xml，所以不要在自动生成的xml中DIY自己的语句

4.说明
1.generatorConfig.xml中：
context的targetRuntime

<context id="mysqlgenerator" targetRuntime="MyBatis3">
    1，MyBatis3：默认的值，生成基于MyBatis3.x以上版本的内容，包括XXXBySample；(常用)
    2，MyBatis3Simple：类似MyBatis3，只是不生成XXXBySample； 

javaClientGenerator的type

对于mybatis来说，即生成Mapper接口，注意，如果没有配置该元素，那么默认不会生成Mapper接口 
type：选择怎么生成mapper接口（在MyBatis3/MyBatis3Simple下）：
1，ANNOTATEDMAPPER：会生成使用Mapper接口+Annotation的方式创建（SQL生成在annotation中），不会生成对应的XML；
2，MIXEDMAPPER：使用混合配置，会生成Mapper接口，并适当添加合适的Annotation，但是XML会生成在XML中；
3，XMLMAPPER：会生成Mapper接口，接口完全依赖XML；
注意，如果context是MyBatis3Simple：只支持ANNOTATEDMAPPER和XMLMAPPER

2.如果要实现生成的文件不要注释并且也是覆盖，需要做如下配置：

1，pom中加true，并且导入1.3.7以上版本的插件；
2，自动生成配置中配置UnmergeableXmlMappersPlugin；
才可以取消生成全部注释。
注意：如果没有取消生成注释，就不用做这些处理，就是覆盖。因为插件是根据自己的注释来确定是否为overwrite还是merge的。

5.搭建运行mybatis的配置
为方便记，分三部曲配置
1.需要配置扫描的xml文件： 在application.xml中配置，

mybatis:
mapper-locations: classpath:com/zxd/testforteaching/mapper/*.xml

2.需要配置扫描的接口文件：
启动类上加 @MapperScan(“com.zxd.testforteaching.dao”) 取src.main.java后面的路径；
或者每个Mapper接口上面加@Mapper注解；

3.需要配置映射的实体类： 两种方式
一。不用配置的情况：用完全限定名来指定这些POJO的引用，例如

1
二。可以通过在application.xml中配置pojo引用路径，就可以不用完全限定名

mybatis:
type-aliases-package: com.zxd.testforteaching.model
-----------------------

6.缺少mybatis配置的一些常见报错信息
org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.zxd.testforteaching.dao.CourseMapper.selectByPrimaryKey
ps 是因为未配置mapper-locations
Caused by: java.lang.ClassNotFoundException: Cannot find class: Course
ps 是因为未扫描到接受的实体类（pojo）
Field courseMapper in com.zxd.testforteaching.controller.TestController required a bean of type 'com.zxd.testforteaching.dao.CourseMapper' that could not be found.
ps 是因为mapper接口未扫描到。

7.最后就可以测试一下mybatis啦~
@RestController
public class TestController {
@Autowired
private CourseMapper courseMapper;
@RequestMapping("/getOne")
public Course getOne(String a){
Course course = courseMapper.selectByPrimaryKey("01");
return course;
}
}
//结果返回 {"cId":"01","cName":"语文","tId":"02"}