第四章🚦Mybatis-支持*匹配扫描包

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📖 本章内容：Mybatis-支持*匹配扫描包

🌳Gitee仓库地址：👉🏽 Mybatis支持*匹配扫描包

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1️⃣ 可以给指定的包起别名
2️⃣ 找到所有的mapper.xml映射文件
3️⃣ 加载全局的配置文件

🍖配置文件信息

# MyBatis配置
mybatis:
  # 搜索指定包别名
  typeAliasesPackage: com.michale.*.entity
  # 配置mapper的扫描，找到所有的mapper.xml映射文件
  mapperLocations: classpath:mapper/*.xml
  # 加载全局的配置文件
  configLocation: classpath:mybatis/mybatis-config.xml

• mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!-- 全局参数 -->
    <settings>
        <!-- 使全局的映射器启用或禁用缓存 -->
        <setting name="cacheEnabled" value="true"/>
        <!-- 允许JDBC 支持自动生成主键 -->
        <setting name="useGeneratedKeys" value="true"/>
        <!-- 配置默认的执行器.SIMPLE就是普通执行器;REUSE执行器会重用预处理语句(prepared statements);BATCH执行器将重用语句并执行批量更新 -->
        <setting name="defaultExecutorType" value="SIMPLE"/>
        <!-- 指定 MyBatis 所用日志的具体实现 -->
        <setting name="logImpl" value="SLF4J"/>
        <!-- 使用驼峰命名法转换字段 -->
        <!-- <setting name="mapUnderscoreToCamelCase" value="true"/> -->
    </settings>
</configuration>

🍵读取配置信息

/**
 * @Author: 花棉袄
 * @CreateDate: 2022年08月29日
 * @Describe: 读取mybatis扫描包
 */
@Data
@Component
@ConfigurationProperties(prefix = "mybatis")
public class MybatisProperties {

    @ApiModelProperty("搜索指定包别名")
    private String typeAliasesPackage;

    @ApiModelProperty("配置mapper的扫描，找到所有的mapper.xml映射文件")
    private String mapperLocations;

    @ApiModelProperty("加载全局的配置文件")
    private String configLocation;
}

🍠Mybatis配置类

/**
 * @Author: 花棉袄
 * @CreateDate: 2022年08月29日
 * @Describe: Mybatis支持*匹配扫描包
 */
@Configuration
public class MyBatisConfig {
    @Autowired
    private MybatisProperties mybatisProperties;

    static final String DEFAULT_RESOURCE_PATTERN = "**/*.class";

    @Bean
    public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception {
        /* 获取配置信息 */
        String typeAliasesPackage = mybatisProperties.getTypeAliasesPackage();
        String mapperLocations = mybatisProperties.getMapperLocations();
        String configLocation = mybatisProperties.getConfigLocation();
        typeAliasesPackage = setTypeAliasesPackage(typeAliasesPackage);
        /* 将指定的类添加到VFS实现列表中 */
        VFS.addImplClass(SpringBootVFS.class);

        /* 依赖Spring容器完成MyBatis的SqlSessionFactory对象的创建 */
        final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        /* 配置数据源 */
        sessionFactory.setDataSource(dataSource);
        /* 配置需要定义别名的实体类的包 */
        sessionFactory.setTypeAliasesPackage(typeAliasesPackage);
        /* 配置mapper文件的路径 */
        sessionFactory.setMapperLocations(resolveMapperLocations(StringUtils.split(mapperLocations, ",")));
        /* 配置mapper文件的路径 */
        sessionFactory.setConfigLocation(new DefaultResourceLoader().getResource(configLocation));
        return sessionFactory.getObject();
    }

    /**
     * typeAliasesPackage 路径扫描
     * @param typeAliasesPackage
     * @return
     */
    public static String setTypeAliasesPackage(String typeAliasesPackage) {
        ResourcePatternResolver resolver = (ResourcePatternResolver) new PathMatchingResourcePatternResolver();
        MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory(resolver);
        List<String> allResult = new ArrayList<String>();
        try {
            for (String aliasesPackage : typeAliasesPackage.split(",")) {
                List<String> result = new ArrayList<String>();
                aliasesPackage = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX
                        + ClassUtils.convertClassNameToResourcePath(aliasesPackage.trim()) + "/" + DEFAULT_RESOURCE_PATTERN;
                Resource[] resources = resolver.getResources(aliasesPackage);
                if (resources != null && resources.length > 0) {
                    MetadataReader metadataReader = null;
                    for (Resource resource : resources) {
                        if (resource.isReadable()) {
                            metadataReader = metadataReaderFactory.getMetadataReader(resource);
                            try {
                                result.add(Class.forName(metadataReader.getClassMetadata().getClassName()).getPackage().getName());
                            } catch (ClassNotFoundException e) {
                                e.printStackTrace();
                            }
                        }
                    }
                }
                if (result.size() > 0) {
                    HashSet<String> hashResult = new HashSet<String>(result);
                    allResult.addAll(hashResult);
                }
            }
            if (allResult.size() > 0) {
                typeAliasesPackage = String.join(",", (String[]) allResult.toArray(new String[0]));
            } else {
                throw new RuntimeException("mybatis typeAliasesPackage 路径扫描错误,参数typeAliasesPackage:" + typeAliasesPackage + "未找到任何包");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return typeAliasesPackage;
    }

    /**
     * mybatisProperties 路径扫描
     * @param mapperLocations
     * @return
     */
    public Resource[] resolveMapperLocations(String[] mapperLocations) {
        ResourcePatternResolver resourceResolver = new PathMatchingResourcePatternResolver();
        List<Resource> resources = new ArrayList<Resource>();
        if (mapperLocations != null) {
            for (String mapperLocation : mapperLocations) {
                try {
                    Resource[] mappers = resourceResolver.getResources(mapperLocation);
                    resources.addAll(Arrays.asList(mappers));
                } catch (IOException e) {
                    // ignore
                }
            }
        }
        return resources.toArray(new Resource[resources.size()]);
    }
}

🍏MybatisPlus扩展

• 配置数据源之后MybatisPlus的增强组件全部失效的问题

• 使用MybatisSqlSessionFactoryBean工厂构建对象

final MybatisSqlSessionFactoryBean sessionFactory = new MybatisSqlSessionFactoryBean();

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