1. First is my project structure and the dependencies I introduced:
2. Introduced dependencies: jdk uses 17
<properties>
<maven.compiler.source>17</maven.compiler.source>
<maven.compiler.target>17</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>dom4j</groupId>
<artifactId>dom4j</artifactId>
<version>1.6.1</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
<!--Do xml parsing-->
<dependency>
<groupId>jaxen</groupId>
<artifactId>jaxen</artifactId>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
3. The test code is as follows:
public class TestMybatis {
@Test
public void testPorerXml() throws DocumentException {
SAXReader saxReader=new SAXReader();
InputStream resourceAsStream = ClassLoader.getSystemClassLoader().getResourceAsStream("mybatis-conf.xml");
Document read = saxReader.read(resourceAsStream);
System.out.println("read = " + read);
String xPath="/configuration/environments";
Element node =(Element) read.selectSingleNode(xPath);
String node1 = node.attributeValue("default");
System.out.println("node1 = " + node1);
String xPath1="/configuration/environments/environment[@id='" + node1 + "']";
System.out.println("xPath1 = " + xPath1);
Elementele = (Element) read.selectSingleNode(xPath1);
System.out.println("ele = " + ele);
Element transactionManager = ele.element("transactionManager");
String transactionManager1 = transactionManager.attributeValue("type");
System.out.println("transactionManager1 = " + transactionManager1);
Element dataSource = ele.element("dataSource");
String pooled = dataSource.attributeValue("type");
System.out.println("pooled = " + pooled);
List<Element> elements = dataSource.elements();
elements.forEach(elem->{
String name = elem.attributeValue("name");
String value = elem.attributeValue("value");
System.out.println("name = " + name + "-----" + "value = " + value);
});
String xpaht2="//mapper";
List<Element> list = read.selectNodes(xpaht2);
for (Element l:list) {
System.out.println("l = " + l);
String resource = l.attributeValue("resource");
System.out.println("resource = " + resource);
}
}
@Test
public void testAdminXml() throws DocumentException {
SAXReader saxReader=new SAXReader();
InputStream resourceAsStream = ClassLoader.getSystemClassLoader().getResourceAsStream("AdminMapper.xml");
Document document = saxReader.read(resourceAsStream);
String path="/mapper";
Element element = (Element) document.selectSingleNode(path);
String namespace = element.attributeValue("namespace");
System.out.println("namespace = " + namespace);
List<Element> elements = element.elements();
elements.forEach(elem->{
String id = elem.attributeValue("id");
System.out.println("id = " + id);
String useGeneratedKeys = elem.attributeValue("useGeneratedKeys");
System.out.println("useGeneratedKeys = " + useGeneratedKeys);
String keyProperty = elem.attributeValue("keyProperty");
System.out.println("keyProperty = " + keyProperty);
String resultType = elem.attributeValue("resultType");
System.out.println("resultType = " + resultType);
String resultMapper = elem.attributeValue("resultMap");
System.out.println("resultMapper = " + resultMapper);
String textTrim = elem.getTextTrim();
System.out.println("textTrim = " + textTrim);
String s = textTrim.replaceAll("#\{[0-9A-Za-z_$]*}", "?");
System.out.println("s = " + s);
});
}
}
4. Talk about what each method is used for and its specific function:
SAXReader saxReader=new SAXReader();
InputStream resourceAsStream = ClassLoader.getSystemClassLoader().getResourceAsStream("mybatis-conf.xml");
Document read = saxReader.read(resourceAsStream);
0. The SAX parser reads the XML file named "mybatis-conf.xml" located on the classpath and parses it into a Document object. Among them, SAXReader is a SAX parser,
InputStream resourceAsStream = ClassLoader.getSystemClassLoader().getResourceAsStream("mybatis-conf.xml") is used to obtain the input stream of the mybatis-conf.xml file,
Document read = saxReader.read(resourceAsStream) parses the input stream into a Document object:
1. Element node =(Element) read.selectSingleNode(xPath);: Get the root node in the mybatis-conf.xml file based on the XPath expression, which is the
2. String node1 = node.attributeValue(“default”);: Get the default attribute value of the
3. String xPath1=”/configuration/environments/environment[@id='” + node1 + “‘]”;: Constructs an XPath expression based on the default attribute value, used to obtain the
4. Element ele = (Element) read.selectSingleNode(xPath1);: Get the
5. Element transactionManager = ele.element(“transactionManager”);: Get the
6. String transactionManager1 = transactionManager.attributeValue(“type”);: Get the type attribute value of the
7. Element dataSource = ele.element(“dataSource”);: Get the
8. String pooled = dataSource.attributeValue(“type”);: Get the type attribute value of the
9. List
10. elements.forEach(elem->{}: Traverse the configuration information of the database connection pool and obtain the name and value attributes of each child node.
11. String xpaht2=”//mapper”;: Constructs an XPath expression to obtain all
12. List
13. for (Element l:list) {}: Traverse all
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