Java获取配置文件路径方式与XML解析

曾经终败给现在 2024-04-17 05:48 49阅读 0赞

Java中最常用的配置文件格式：

*  \*.xml
 *  \*.proerties

XML解析方式

*  sax:[http://www.saxproject.org/quickstart.html][http_www.saxproject.org_quickstart.html]
 *  dom:[https://www.w3school.com.cn/xmldom/index.asp][https_www.w3school.com.cn_xmldom_index.asp]
 *  dom4j:[https://dom4j.github.io/][https_dom4j.github.io]

**目录**

JavaPath 获取

Java解析XML的三种方式

SAX

DOM

DOM4j

--------------------

## JavaPath 获取 ##

package com.boonya.path;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.util.Properties;
    import javax.servlet.ServletContext;
    import javax.servlet.http.HttpServletRequest;
    /**
     * Java 中配置文件的读取方式
     * @packge com.boonya.path.JavaPath
     * @date   2019年8月23日  下午10:42:48
     * @author pengjunlin
     * @comment   
     * @update
     */
    public class JavaPath {
    	
    	/**
    	 * 读取与类同级的properties文件
    	 * @MethodName: getPropertiesIn 
    	 * @Description: 
    	 * @param clazz
    	 * @param propertiesPath
    	 * @return
    	 * @throws IOException
    	 * @throws
    	 */
    	@SuppressWarnings("rawtypes")
    	public static Properties getProperties(Class clazz,String propertiesPath) throws IOException{
    		InputStream is= clazz.getResourceAsStream(propertiesPath);
    		Properties p=new Properties();
    		p.load(is);
    		return p;
    	}
    	
    	/**
    	 * 读取资源与类同级的properties文件
    	 * @MethodName: getPropertiesIn 
    	 * @Description: 
    	 * @param clazz
    	 * @param propertiesPath
    	 * @return
    	 * @throws IOException
    	 * @throws
    	 */
    	public static Properties getResourceProperties(String propertiesPath) throws IOException{
    		InputStream is= JavaPath.class.getResourceAsStream("/"+propertiesPath);
    		Properties p=new Properties();
    		p.load(is);
    		return p;
    	}
    	
    	/**
    	 * 读取WEB-INF路径下的properties文件
    	 * @MethodName: getProperties 
    	 * @Description: 
    	 * @param request
    	 * @param webInfPropertiesPath
    	 * @return
    	 * @throws IOException
    	 * @throws
    	 */
    	public static Properties getProperties(HttpServletRequest request,String webInfPropertiesPath) throws IOException{
    		ServletContext context=request.getSession().getServletContext();
    		InputStream is=context.getResourceAsStream(webInfPropertiesPath);
    		Properties p=new Properties();
    		p.load(is);
    		return p;
    	}
    	
    	public static void main(String[] args) throws IOException {
    		Properties pro=JavaPath.getResourceProperties("Test.properties");
    		System.out.println(pro.getProperty("server"));
    		System.out.println(pro.getProperty("port"));
    	}
    
    }

参考地址：[https://www.cnblogs.com/omji0030/p/11000040.html][https_www.cnblogs.com_omji0030_p_11000040.html]

## Java解析XML的三种方式 ##

### SAX ###

package com.boonya.xml;
     
    import org.xml.sax.Attributes;
    import org.xml.sax.SAXException;
    import org.xml.sax.helpers.DefaultHandler;
     
    //
    public class Saxhandler extends DefaultHandler {
     
        @Override
        public void startDocument() throws SAXException {
            System.out.println("开始解析XML文档...");
        }
     
        @Override
        public void endDocument() throws SAXException {
            System.out.println("结束解析XML文档...");
        }
     
        @Override
        public void startElement(String uri, String localName, String qName,
                Attributes attributes) throws SAXException {
            // TODO Auto-generated method stub
            super.startElement(uri, localName, qName, attributes);
            System.out.println("开始解析节点["+qName+"]...");
            System.out.println("共有["+attributes.getLength()+"]个属性");
        }
     
        @Override
        public void characters(char[] ch, int start, int length)
                throws SAXException {
            // TODO Auto-generated method stub
            super.characters(ch, start, length);
            String content =new String(ch,start,length);
            System.out.println(content);
        }
     
        @Override
        public void endElement(String uri, String localName, String qName)
                throws SAXException {
            // TODO Auto-generated method stub
            super.endElement(uri, localName, qName);
            System.out.println("结束解析XML节点...");
        }
    }

### DOM ###

package com.boonya.xml;
     
    import java.util.Iterator;
     
    import javax.xml.parsers.DocumentBuilder;
    import javax.xml.parsers.DocumentBuilderFactory;
     
    import org.w3c.dom.Document;
    import org.w3c.dom.Element;
    import org.w3c.dom.NamedNodeMap;
    import org.w3c.dom.Node;
    import org.w3c.dom.NodeList;
     
    public class DomHandler {
     
        /*
         * 解析XML
         */
        public void read(String fileName) throws Exception {
            // 定义工厂API 使应用程序能够从XML文档获取生成DOM对象树的解析器
            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            // 获取此类的实例之后，将可以从各种输入源解析XML
            DocumentBuilder builder = factory.newDocumentBuilder();
            // builder.parse(this.getClass().getResourceAsStream("/" + fileName));
            // Document接口表示整个HTML或XML文档，从概念上讲，它是文档树的根，并提供对文档数据的基本访问
            Document document = builder.parse(this.getClass().getResourceAsStream(
                    "/" + fileName));
            // 获取根节点
            Element root = document.getDocumentElement();
            System.out.println(root.getNodeName());
     
            //读取database节点NodeList接口提供对节点的有序集合的抽象
            NodeList nodeList = root.getElementsByTagName("database");
            for (int i = 0; i < nodeList.getLength(); i++) {
                // 获取一个节点
                Node node = nodeList.item(i);
                // 获取该节点所有属性
                NamedNodeMap attributes = node.getAttributes();
                for (int j = 0; j < attributes.getLength(); j++) {
                    Node attribute = attributes.item(j);
                    System.out.println(attribute.getNodeName() + ":"
                            + attribute.getNodeValue());
                }
                //获取所有子节点数据
                NodeList childNodes=node.getChildNodes();
                for (int j = 0; j < childNodes.getLength(); j++) {
                    Node childNode=childNodes.item(j);
                    System.out.println(childNode.getNodeName()+":"+childNode.getNodeValue());
                }
            }
        }
     
        public static void main(String[] args) throws Exception {
            new DomHandler().read("data-source.xml");
     
        }
    }

### DOM4j ###

package com.boonya.xml;
    
    import java.io.FileOutputStream;
    import java.sql.DatabaseMetaData;
    import java.util.Iterator;
    import java.util.List;
    
    import org.dom4j.*;
    import org.dom4j.io.OutputFormat;
    import org.dom4j.io.SAXReader;
    import org.dom4j.io.XMLWriter;
    
    public class Dom4jHandler {
    
    	public void add() throws Exception {
    		// 1.创建一个Document
    		Document document = DocumentHelper.createDocument();
    		// 2.给Document添加数据
    		Element root = document.addElement("DataSource");
    		// 添加注释
    		root.addComment("这是注释信息");
    		// 在root根节点下面添加一个子节点
    		Element database = root.addElement("database");
    		database.addAttribute("name", "mysql");
    		database.addAttribute("version", "5.0");
    		// 添加子节点
    		database.addElement("driver").setText("com.mysql.jdbc.Driver");
    		database.addElement("url")
    				.setText("jdbc:mysql://localhost:3306/myjdbc");
    		database.addElement("user").setText("root");
    		database.addElement("password").setText("root");
    		// 3.将Document写出文件
    		OutputFormat format = OutputFormat.createPrettyPrint();
    		format.setEncoding("utf-8");
    		// FileOutputStream默认生成的路径在根路径
    		XMLWriter xw = new XMLWriter(new FileOutputStream("db.xml"), format);
    		xw.write(document);
    		xw.close();
    	}
    
    	public void update(String fileName) throws Exception {
    		// sax解析器
    		SAXReader saxReader = new SAXReader();
    		// 读到对象
    		Document document = saxReader.read(this.getClass().getResourceAsStream(
    				"/" + fileName));
    		Element root = document.getRootElement();
    		List<Element> databases_node = root.elements("database");
    		for (Element database_node : databases_node) {
    			if (database_node.attributeValue("name").equalsIgnoreCase("mysql")) {
    				System.out.println("old:"
    						+ database_node.attributeValue("name"));
    				database_node.attribute("name").setText("Oracle");
    				System.out.println("update:"
    						+ database_node.attributeValue("name"));
    
    				database_node.element("driver").setText("oracel");
    				database_node.element("url").setText("jdbc");
    
    				// 删除password节点
    				database_node.remove(database_node.element("password"));
    
    				// 删除属性
    				database_node.remove(database_node.attribute("version"));
    			}
    		}
    
    		OutputFormat format = OutputFormat.createPrettyPrint();
    		format.setEncoding("utf-8");
    		// FileOutputStream默认生成的路径在根路径
    		XMLWriter xw = new XMLWriter(new FileOutputStream("db2.xml"), format);
    		xw.write(document);
    		xw.close();
    	}
    
    	public void read(String fileName) throws Exception {
    		// sax解析器
    		SAXReader saxReader = new SAXReader();
    		// 读到对象
    		Document document = saxReader.read(this.getClass().getResourceAsStream(
    				"/" + fileName));
    		Element root = document.getRootElement();
    		System.out.println("根节点：" + root.getName());
    
    		// List<Element> childElements=root.elements();
    		List<Element> childElements = root.elements("database");
    		for (Element child : childElements) {
    			// 获取属性 不知道属性名称时的遍历方法
    			List<Attribute> attributes = child.attributes();
    			// for (Attribute attribute : attributes) {
    			// System.out.println(attribute.getName()+":"+attribute.getValue());
    			// }
    			String name = child.attributeValue("name");
    			// String version = child.attributeValue("version");
    			String version = child.attribute("version").getValue();
    			System.out.println(name + ":" + version);
    
    			// //获取子节点
    			// List<Element> childs=child.elements();
    			// for (Element element : childs) {
    			// System.out.println(element.getName()+":"+element.getText());
    			// }
    			System.out.println(child.elementText("driver"));
    			System.out.println(child.element("url").getText());
    			System.out.println(child.elementTextTrim("user"));
    			System.out.println(child.element("password").getTextTrim());
    
    		}
    	}
    
    	public static void main(String[] args) throws Exception {
    		// new Dom4jHandler().read("data-source.xml");
    		// new Dom4jHandler().add();
    		new Dom4jHandler().update("data-source.xml");
    	}
    }

Dom4j获取文档：

package com.boonya.xml;
    
    import java.io.File;
    import java.io.InputStream;
    import java.net.URL;
    import org.dom4j.Document;
    import org.dom4j.DocumentException;
    import org.dom4j.io.SAXReader;
    
    public class Dom4jXMLParser {
    	
    	/**
    	 * 获得XML文档对象（InputStream is = Dom4jXMLParser.class.getResourceAsStream("/Test.xml");）
    	 * @MethodName: getDocument 
    	 * @Description: 
    	 * @param is
    	 * @return
    	 * @throws
    	 */
    	public static Document getDocument(InputStream is) {  
    		Document document=null;
    		try {
    			SAXReader saxReader = new SAXReader();
    			document = saxReader.read(is);
    		} catch (DocumentException e) {
    			e.printStackTrace();
    		}
    	    return document;  
    	}
    	
    	/**
    	 * 获得XML文档对象
    	 * @MethodName: getDocument 
    	 * @Description: 
    	 * @param filePath
    	 * @return
    	 * @throws
    	 */
    	public static Document getDocument(String filePath) {  
    	    Document document = null;  
    	    try {  
    	        SAXReader saxReader = new SAXReader();  
    	        document = saxReader.read(new File(filePath)); 
    	    } catch (Exception ex) {  
    	        ex.printStackTrace();  
    	    }  
    	    return document;  
    	}  
    	
    	/**
    	 * 获得网络XML文档对象
    	 * @MethodName: getDocument 
    	 * @Description: 
    	 * @param url
    	 * @return
    	 * @throws
    	 */
    	public static Document getDocument(URL url) {  
    	    Document document = null;  
    	    try {  
    	        SAXReader saxReader = new SAXReader();  
    	        document = saxReader.read(url);
    	    } catch (Exception ex) {  
    	        ex.printStackTrace();  
    	    }  
    	    return document;  
    	}  
    
    	public static void main(String[] args) throws DocumentException {
    		
    	}
    
    }

Dom4j完整教程：[https://blog.csdn.net/chenweitang123/article/details/6255108][https_blog.csdn.net_chenweitang123_article_details_6255108]

[http_www.saxproject.org_quickstart.html]: http://www.saxproject.org/quickstart.html
[https_www.w3school.com.cn_xmldom_index.asp]: https://www.w3school.com.cn/xmldom/index.asp
[https_dom4j.github.io]: https://dom4j.github.io/
[https_www.cnblogs.com_omji0030_p_11000040.html]: https://www.cnblogs.com/omji0030/p/11000040.html
[https_blog.csdn.net_chenweitang123_article_details_6255108]: https://blog.csdn.net/chenweitang123/article/details/6255108