使用Java代码配置MyBatis Generator

　　使用MyBatis Generator生成器时，有时候没办法使用xml型的配置文件，比如将Maven项目设置成pom打包方式(<packaging>pom</packaging>)！由于Maven的工作机制对于打包方式为pom的项目是不会输出jar包或war和resources内容，所以放在resources目录下或放在源码目录下的xml文件就没法读取了，就算你在pom.xml文件中明确有如下配置也没有用的：

    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.yml</include>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.yml</include>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>
    </build>

　　这个时候就会用到纯Java代码的MyBatis Generator配置，直接贴配置代码：

import org.mybatis.generator.config.*;

/**
 * 基础Java代码的MBG配置
 * Maven打包方式为POM的项目或模块(<packaging>pom</packaging>)，resources目录的内容不会输出到类路径下，所以可以选择直接使用Java代码配置！
 *
 * @author 707669522@qq.com
 * @since 2020-06-13
 */
public class GeneratorConfig {
    public static Configuration getGeneratorConfig() {
        Context context = new Context(ModelType.CONDITIONAL);
        context.setId("simple");
        context.setTargetRuntime("MyBatis3Simple");

        /*添加属性*/
        context.addProperty("javaFileEncoding", "UTF-8");

        /*插件配置，这个是我自己的插件，没有自定义插件的同学可以不配这一节，删除即可*/
        PluginConfiguration pluginConfig = new PluginConfiguration();
        pluginConfig.setConfigurationType("com.xgclassroom.generator.GeneratorPlugin");
        context.addPluginConfiguration(pluginConfig);

        /*注释生成器配置*/
        CommentGeneratorConfiguration commentGeneratorConfig = new CommentGeneratorConfiguration();
        commentGeneratorConfig.addProperty("suppressAllComments", "true");
        context.setCommentGeneratorConfiguration(commentGeneratorConfig);

        /*JDBC连接信息配置*/
        JDBCConnectionConfiguration jdbcConnectionConfig = new JDBCConnectionConfiguration();
        jdbcConnectionConfig.setDriverClass("com.mysql.cj.jdbc.Driver");
        //注意代码配置中JDBC连接字符串中的参数分隔符不需要再像xml配置文件中那样使用转义符
        jdbcConnectionConfig.setConnectionURL("jdbc:mysql://localhost:3306/permission_center?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&useSSL=false");
        jdbcConnectionConfig.setUserId("xurm");
        jdbcConnectionConfig.setPassword("1qaz@WSX");
        jdbcConnectionConfig.addProperty("nullCatalogMeansCurrent", "true");//MySQL无法识别table标签中schema类的配置，所以在URL上指明目标数据库，并追加nullCatalogMeansCurrent属性为true
        jdbcConnectionConfig.addProperty("remarksReporting", "true");//针对oracle数据库无法读取表和字段备注
        jdbcConnectionConfig.addProperty("useInformationSchema", "true");//针对mysql数据库无法读取表和字段备注
        context.setJdbcConnectionConfiguration(jdbcConnectionConfig);

        /*Model生成器配置*/
        JavaModelGeneratorConfiguration javaModelGeneratorConfig = new JavaModelGeneratorConfiguration();
        javaModelGeneratorConfig.setTargetProject("permission/src/main/java");//目标项目(源码主路径)
        javaModelGeneratorConfig.setTargetPackage("com.xgclassroom.model");//目标包(Model类文件存放包)
        context.setJavaModelGeneratorConfiguration(javaModelGeneratorConfig);

        /*SqlMapper生成器配置(*Mapper.xml类文件)，要javaClient生成器类型配合*/
        SqlMapGeneratorConfiguration sqlMapGeneratorConfig = new SqlMapGeneratorConfiguration();
        sqlMapGeneratorConfig.setTargetProject("permission/src/main/java");//目标项目(源码主路径)
        sqlMapGeneratorConfig.setTargetPackage("com.xgclassroom.mapper");//目标包(*Mapper.xml类文件存放包)
        context.setSqlMapGeneratorConfiguration(sqlMapGeneratorConfig);

        /*JavaClient生成器配置(*Mapper.java类文件)*/
        JavaClientGeneratorConfiguration javaClientGeneratorConfig = new JavaClientGeneratorConfiguration();
        javaClientGeneratorConfig.setConfigurationType("XMLMAPPER");//JavaClient生成器类型(主要有ANNOTATEDMAPPER、MIXEDMAPPER、XMLMAPPER，要Context的TargetRuntime配合)
        javaClientGeneratorConfig.setTargetProject("permission/src/main/java");//目标项目(源码主路径)
        javaClientGeneratorConfig.setTargetPackage("com.xgclassroom.mapper");//目标包(*Mapper.java类文件存放包)
        context.setJavaClientGeneratorConfiguration(javaClientGeneratorConfig);

        /*表生成配置*/
        TableConfiguration tableConfig = new TableConfiguration(context);
        tableConfig.setTableName("%");
        GeneratedKey generatedKey = new GeneratedKey("id", "JDBC", true, null);//设置主键列和生成方式
        tableConfig.setGeneratedKey(generatedKey);
        context.addTableConfiguration(tableConfig);

        Configuration config = new Configuration();
        config.addContext(context);

        return config;
    }
}

　　然后就是把MyBatis Generator调用过程中原本读取xml配置文件的地方换掉就可以了：

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

import java.util.ArrayList;
import java.util.List;

/**
 * MyBatisGenerator代码生成器Java调用程序
 *
 * @author 707669522@qq.com
 * @since 2020-06-13
 */
public class GeneratorRunner {
    public static void main(String[] args) {
        try {
            List<String> warnings = new ArrayList<String>();
            Configuration config;
            //使用xml配置文件的方式
            /*File configFile = new File(GeneratorRunner.class.getClassLoader().getResource("generatorConfig.xml").getPath());
            ConfigurationParser cp = new ConfigurationParser(warnings);
            config = cp.parseConfiguration(configFile);*/
            //使用纯Java代码配置的方式
            config = GeneratorConfig.getGeneratorConfig();
            DefaultShellCallback callback = new DefaultShellCallback(true);
            MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
            myBatisGenerator.generate(null);
        } catch (Exception e) {
            System.out.println(e.getMessage());
            e.printStackTrace();
        }
    }
}

　　Talk is cheap, show me the code! Bye.