项目结构
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描述一下自定义持久层框架的项目结构？文章源自浅海拾贝-https://blog.terwergreen.com/custom-code-implementation-of-the-long-lasting-layer-framework-zjoe17.html
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. ├── IPersistence │ ├── IPersistence.iml │ ├── pom.xml │ └── src └── IPersistence_test ├── IPersistence_test.iml ├── pom.xml ├── src └── target
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具体代码
sqlMapperConfig.xml 配置文件
<configuration>
<!-- 存放数据库配置信息 -->
<dataSource>
<property name="driverClass" value="com.mysql.jdbc.Driver"></property>
<property name="jdbcUrl" value="jdbc:mysql://localhost:3306/zdy_mybatis"></property>
<property name="username" value="root"></property>
<property name="password" value="123456"></property>
</dataSource>
<!-- 存放mapper.xml全路径 -->
<mapper resource="UserMapper.xml" />
</configuration>
UserMapper.xml 配置文件
<mapper namespace="user">
<!-- sql的唯一标识：namespace.id组合：statementId -->
<select id="selectList" resultType="com.terwergreen.pojo.User">
select * from user
</select>
<select id="selectOne" resultType="com.terwergreen.pojo.User" parameterType="com.terwergreen.pojo.User">
select * from user where id = #{id} and username = #{username}
</select>
</mapper>
读取资源处理，Resources 类
/**
* 资源处理类
*
* @name: Resource
* @author: terwer
* @date: 2022-03-14 12:57
**/
public class Resources {
/**
* 根据配置文件的路径，将配置文件加载成字节输入流，存储到内存中
*
* @param path
* @return
*/
public static InputStream getResourceAsStream(String path) {
InputStream inputStream = Resources.class.getClassLoader().getResourceAsStream(path);
return inputStream;
}
}
SqlSessionFactoryBuider 工厂构建对象
/**
* 工厂构建对象
*
* @name: SqlSessionFactoryBuilder
* @author: terwer
* @date: 2022-03-14 15:18
**/
public class SqlSessionFactoryBuilder {
public SqlSessionFactory build(InputStream in) throws DocumentException, PropertyVetoException {
// 1、解析配置文件，将解析出来的内容封装到Configuration中
XmlConfigBuilder xmlConfigBuilder = new XmlConfigBuilder();
Configuration configuration = xmlConfigBuilder.parse(in);
// 2、创建SqlSessionFactory对象
DefaultSqlSessionFactory sqlSessionFactory = new DefaultSqlSessionFactory(configuration);
return sqlSessionFactory;
}
}
配置文件解析
/**
* @name: XmlConfigBuilder
* @author: terwer
* @date: 2022-03-14 15:40
**/
public class XmlConfigBuilder {
private Configuration configuration;
public XmlConfigBuilder() {
configuration = new Configuration();
}
/**
* 使用dom4j将配置文件进行解析，封装Configuration
*
* @param in
* @return
*/
public Configuration parse(InputStream in) throws DocumentException, PropertyVetoException {
Document document = new SAXReader().read(in);
// <confiruration>
Element rootElement = document.getRootElement();
List<Element> list = rootElement.selectNodes("//property");
Properties properties = new Properties();
for (Element element : list) {
String name = element.attributeValue("name");
String value = element.attributeValue("value");
properties.setProperty(name, value);
}
ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
comboPooledDataSource.setDriverClass(properties.getProperty("driverClass"));
comboPooledDataSource.setJdbcUrl(properties.getProperty("jdbcUrl"));
comboPooledDataSource.setUser(properties.getProperty("username"));
comboPooledDataSource.setPassword(properties.getProperty("password"));
configuration.setDataSource(comboPooledDataSource);
// mapper.xml解析，拿到路径，加载成字节输入流，进行解析
List<Element> mapperList= rootElement.selectNodes("//mapper");
// <mapper>
for (Element element : mapperList) {
String mapperPath = element.attributeValue("resource");
InputStream resourceAsStream = Resources.getResourceAsStream(mapperPath);
XmlMapperBuilder xmlMapperBuilder = new XmlMapperBuilder(configuration);
xmlMapperBuilder.parse(resourceAsStream);
}
return configuration;
}
}
mapper 映射文件解析
/**
* mapper解析器
*
* @name: XmlMapperBuilder
* @author: terwer
* @date: 2022-03-14 16:16
**/
public class XmlMapperBuilder {
private Configuration configuration;
public XmlMapperBuilder(Configuration configuration) {
this.configuration = configuration;
}
public void parse(InputStream in) throws DocumentException {
Document document = new SAXReader().read(in);
// <mapper>
Element rootElement = document.getRootElement();
String namespace = rootElement.attributeValue("namespace");
List<Element> list = rootElement.selectNodes("//select");
for (Element element : list) {
String id = element.attributeValue("id");
String resultType = element.attributeValue("resultType");
String parameterType = element.attributeValue("parameterType");
String sqlText = element.getTextTrim();
MappedStatement mappedStatement = new MappedStatement();
mappedStatement.setStatementId(id);
mappedStatement.setResultType(resultType);
mappedStatement.setParameterType(parameterType);
mappedStatement.setSql(sqlText);
Map<String, MappedStatement> mappedStatementMap = configuration.getMappedStatementMap();
String statementId = namespace + "." + id;
mappedStatementMap.put(statementId, mappedStatement);
}
}
}
SqlSession 的具体实现
/**
* @name: SqlSession
* @author: terwer
* @date: 2022-03-14 16:35
**/
public interface SqlSession {
/**
* 查询所有
*/
public <E> List<E> selectList(String statementId, Object... params) throws Exception;
/**
* 查询单个
*/
public <T> T selectOne(String statementId, Object... params) throws Exception;
public <T> T getMapper(Class<?> mapperClass);
}
文章更新历史文章源自浅海拾贝-https://blog.terwergreen.com/custom-code-implementation-of-the-long-lasting-layer-framework-zjoe17.html
2024/04/13 同步文章到其他平台文章源自浅海拾贝-https://blog.terwergreen.com/custom-code-implementation-of-the-long-lasting-layer-framework-zjoe17.html
2022/05/08 feat: 优化代码 文章源自浅海拾贝-https://blog.terwergreen.com/custom-code-implementation-of-the-long-lasting-layer-framework-zjoe17.html
文章源自浅海拾贝-https://blog.terwergreen.com/custom-code-implementation-of-the-long-lasting-layer-framework-zjoe17.html
本文介绍了一个基于Java和Kotlin的MyBatis框架示例项目的结构和关键代码部分，包括配置文件、Mapper文件、资源处理类以及SqlSessionFactory的构建对象。示例项目用于展示如何配置MyBatis，读取资源，构建SqlSessionFactory，以便进行数据库操作。文章源自浅海拾贝-https://blog.terwergreen.com/custom-code-implementation-of-the-long-lasting-layer-framework-zjoe17.html
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