What is a configuration file in Java
Configuration file names in Java generally end with ".properties" and ".xml" , the structure of these configuration files is the same as Java's HashMap structure. Its function is to change the parameters in the code by modifying the configuration file, thereby achieving flexible parameter changes.
properties usage
driver=com.mysql.jdbc.Driver jdbcUrl=jdbc:mysql://localhost:3306/user user=root password=123456
/** * 讀取config.properties文件中的內(nèi)容,放到Properties類中 * @param filePath 文件路徑 * @param key 配置文件中的key * @return 返回key對(duì)應(yīng)的value */ public static String readConfigFiles(String filePath,String key) { Properties prop = new Properties(); try{ InputStream inputStream = new FileInputStream(filePath); prop.load(inputStream); inputStream.close(); return prop.getProperty(key); }catch (Exception e) { e.printStackTrace(); System.out.println("未找到相關(guān)配置文件"); return null; } }
xml usage
<?xml version="1.0" encoding="utf-8" ?> <class> <student> <firstname>cxx1</firstname> <lastname>Bob1</lastname> <nickname>stars1</nickname> <marks>85</marks> </student> <student rollno="493"> <firstname>cxx2</firstname> <lastname>Bob2</lastname> <nickname>stars2</nickname> <marks>85</marks> </student> <student rollno="593"> <firstname>cxx3</firstname> <lastname>Bob3</lastname> <nickname>stars3</nickname> <marks>85</marks> </student> </class>
package com.cxx.xml; import org.w3c.dom.*; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; /** * @Author: cxx * Dom操作xml * @Date: 2018/5/29 20:19 */ public class DomDemo { //用Element方式 public static void element(NodeList list){ for (int i = 0; i <list.getLength() ; i++) { Element element = (Element) list.item(i); NodeList childNodes = element.getChildNodes(); for (int j = 0; j <childNodes.getLength() ; j++) { if (childNodes.item(j).getNodeType()==Node.ELEMENT_NODE) { //獲取節(jié)點(diǎn) System.out.print(childNodes.item(j).getNodeName() + ":"); //獲取節(jié)點(diǎn)值 System.out.println(childNodes.item(j).getFirstChild().getNodeValue()); } } } } public static void node(NodeList list){ for (int i = 0; i <list.getLength() ; i++) { Node node = list.item(i); NodeList childNodes = node.getChildNodes(); for (int j = 0; j <childNodes.getLength() ; j++) { if (childNodes.item(j).getNodeType()==Node.ELEMENT_NODE) { System.out.print(childNodes.item(j).getNodeName() + ":"); System.out.println(childNodes.item(j).getFirstChild().getNodeValue()); } } } } public static void main(String[] args) { //1.創(chuàng)建DocumentBuilderFactory對(duì)象 DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); //2.創(chuàng)建DocumentBuilder對(duì)象 try { DocumentBuilder builder = factory.newDocumentBuilder(); Document d = builder.parse("src/main/resources/demo.xml"); NodeList sList = d.getElementsByTagName("student"); //element(sList); node(sList); } catch (Exception e) { e.printStackTrace(); } } }
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