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MyBatis之xml配置的解析

下文笔者讲述Mybatis之xml配置解析的相关简介说明,如下所示
下文笔者讲述使用XMLConfigBuilder类
读取xml文件并生成一个DataSource
使用xml配置一个DataSource
xml格式如下所示:

com.mysql.jdbc.Driverjdbc:mysql://localhost:3306/mysqldb?useUnicode=true&characterEncoding=utf8root123456

dom4j

dom4j可用于读取每一个节点的标签、属性、子节点等
而且使用较为简单,只需要输入流或文件即可解析
例: 使用dom4j,先引入dom4j相应的jar包

dom4jdom4j1.6.1

编写相应的示例代码

// InputStream in;
SAXReader reader = new SAXReader();
Document document = reader.read(in);
Element root = document.getRootElement();
String tagName = root.getName();    // 标签名
for (Object item : root.elements("xxx")) {// e表示root的标签名为xxx的孩子Element e = (Element) item;
}

XMLConfigure之获取配置信息

private static ClassLoader loader = ClassLoader.getSystemClassLoader();public static DataSource build(String resource)
{try {InputStream stream = loader.getResourceAsStream(resource);SAXReader reader = new SAXReader();Document document = reader.read(stream);Element root = document.getRootElement();// Element代入，生成DataSourcereturn evalDataSource(root);} catch (Exception e) {throw new RuntimeException("error occured while evaling xml " + resource);}
}//内容解析
public static DataSource evalDataSource(Element node) throws ClassNotFoundException 
{if (!node.getName().equals("database")) {throw new RuntimeException("root should be ");}String driverClassName = null;String url = null;String username = null;String password = null;for (Object item : node.elements("property")) {Element i = (Element) item;         String value = getValue(i);String name = i.attributeValue("name");if (name == null || value == null) throw new RuntimeException("[database]:  should contain name and value");switch (name) {case "url" : url = value; break;case "username" : username = value; break;case "password" : password = value; break;case "driverClassName" : driverClassName = value; break; default : throw new RuntimeException("[database]:  unknown name"); }}return new VDataSource(driverClassName, url, username, password);
}//测试代码
DataSource ds = XMLConfigBuilder.build("config.xml");
Session session = new VSession(data);
session.exec("select * from users where id<8");