mybatis提供代了碼生成器來(lái)簡(jiǎn)化我們的開(kāi)發(fā)工作，只要我們?cè)跀?shù)據(jù)庫(kù)中創(chuàng)建好數(shù)據(jù)表，然后通過(guò)代碼生成器就可以一鍵生成表相關(guān)的entity、Mapper接口以及xxxMapper.xml映射配置文件，然后把生成的信息導(dǎo)入到相應(yīng)項(xiàng)目就可以進(jìn)行我們開(kāi)發(fā)工作了。

一、基于java代碼的生成器

1.創(chuàng)建maven項(xiàng)目并導(dǎo)入相應(yīng)的mybatis需要的包

<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>
    <groupId>com.qiu</groupId>
    <artifactId>mybatis</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        
    <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.4.4</version>
    </dependency>
    <!-- mybatis-generator-core 反向生成java代碼 -->
    <dependency>
        <groupId>org.mybatis.generator</groupId>
        <artifactId>mybatis-generator-core</artifactId>
        <version>1.3.5</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.36</version>
    </dependency>
    </dependencies>
</project>

2.配置代碼生成器相關(guān)的xml（generator.xml）

在classpath路徑下面創(chuàng)建generator.xml，進(jìn)行配置時(shí)候需要注意的是在generator.xml中標(biāo)簽是有順序的，按下面的進(jìn)行配置就行

<?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="testTables" targetRuntime="MyBatis3">  
        <commentGenerator>  
            <!-- 是否去除自動(dòng)生成的注釋 true：是 ： false:否 -->  
            <property name="suppressAllComments" value="true" />  
        </commentGenerator>  
        <!--數(shù)據(jù)庫(kù)連接的信息：驅(qū)動(dòng)類、連接地址、用戶名、密碼 -->  
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"  
            connectionURL="jdbc:mysql://localhost:3306/mybatis" userId="root"  
            password="123456">  
        </jdbcConnection>  
        <!-- 默認(rèn)false，把JDBC DECIMAL 和 NUMERIC 類型解析為 Integer，為 true時(shí)把JDBC DECIMAL 和   
            NUMERIC 類型解析為java.math.BigDecimal -->  
        <javaTypeResolver>  
            <property name="forceBigDecimals" value="false" />  
        </javaTypeResolver>  
  
        <!-- targetProject:生成PO類的位置 -->  
        <javaModelGenerator targetPackage="com.qiu.entity"  
            targetProject=".\src\main\java">  
            <!-- enableSubPackages:是否讓schema作為包的后綴 -->  
            <property name="enableSubPackages" value="false" />  
            <!-- 從數(shù)據(jù)庫(kù)返回的值被清理前后的空格 -->  
            <property name="trimStrings" value="true" />  
        </javaModelGenerator>  
        <!-- targetProject:mapper映射文件生成的位置 -->  
        <sqlMapGenerator targetPackage="mapper"   
            targetProject=".\src\main\resource">  
            <!-- enableSubPackages:是否讓schema作為包的后綴 -->  
            <property name="enableSubPackages" value="false" />  
        </sqlMapGenerator>  
        <!-- targetPackage：mapper接口生成的位置 -->  
        <javaClientGenerator type="XMLMAPPER"  
            targetPackage="com.qiu.dao"   
            targetProject=".\src\main\java">  
            <!-- enableSubPackages:是否讓schema作為包的后綴 -->  
            <property name="enableSubPackages" value="false" />  
        </javaClientGenerator>  
  <!--逆向工程不生成example類-->
    <!-- 列出要生成代碼的所有表，這里配置的是不生成Example文件 -->    
        <table tableName="tb_user" domainObjectName="UserInfo"    
               enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false"    
               enableSelectByExample="false" selectByExampleQueryId="false" >    
            <property name="useActualColumnNames" value="false"/>    
        </table>  
    </context>  
</generatorConfiguration> 

3.創(chuàng)建java類用于執(zhí)行生成代碼

import java.io.File;
import java.util.ArrayList;
import java.util.List;



import org.mybatis.generator.api.MyBatisGenerator;
import org.mybatis.generator.config.Configuration;
import org.mybatis.generator.config.xml.ConfigurationParser;
import org.mybatis.generator.internal.DefaultShellCallback;

public class Generator {
    public void generator() throws Exception{  
          
        List<String> warnings = new ArrayList<String>();  
//已經(jīng)創(chuàng)建了是否覆蓋
        boolean overwrite = true;  
//注意這里最好采用絕對(duì)路徑，否則容易出現(xiàn)找不到文件
        File configFile = new File("C:\\Users\\Administrator\\Workspaces\\MyEclipse Professional 2014\\myblog\\src\\main\\java\\generator\\generator.xml");   
        ConfigurationParser cp = new ConfigurationParser(warnings);  
        Configuration config = cp.parseConfiguration(configFile);  
        DefaultShellCallback callback = new DefaultShellCallback(overwrite);  
        MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config,  
                callback, warnings);  
        myBatisGenerator.generate(null);  
  
    }   
    public static void main(String[] args) throws Exception {  
        try {  
            Generator generatorSqlmap = new Generator();  
            generatorSqlmap.generator();  
           System.out.println("mybatis 代碼生成成功。。。");
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
          
    }  

}

二、基于maven文件自動(dòng)生成

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