深入解析Properties属性类及其应用

属性类 Properties

Properties 类本身是 HashTable 类的子类&＃xff0c;数据存放也是按照key和value的形式存放数据的。

public class Properties extends HashTable<Object, Object>

Properties 类的主要方法&＃xff1a;

• public Properties() //构造一个空的属性类
• public Properties(Properties defaults) //构造一个指定属性内容的类
• public String getProperty(String key) //根据属性的key取得属性的value&＃xff0c;如果没有key则返回null
• public String getProperty(String key, String defaultValue) //根据属性的key取得属性的value&＃xff0c;如果没有key&＃xff0c;则返回defaultValue
• public Object setProperty(String key, String value) //设置属性
• public void list(PrintStream ouot) //属性打印
• public void load(InputStream inStream) throws IOException //从输入流中取出全部的属性内容
• public void loadFormXML(InputStream in) throws IOException, InvalidPropertiesFormatException //从XML文件格式中读取内容
• public void store(OutputStream os, String comment) throws IOException //将属性内容通过输出流输出&＃xff0c;同时声明属性的注释
• public void storeToXML(OutputStream os, String comment) throws IOException //以XML文件格式输出属性&＃xff0c;默认编码
• public void storeToXML(OutputStream os, String comment, String encoding) throws IOException //以XML文件格式输出&＃xff0c;用户指定默认编码

import java.io.*;
import java.util.Properties;/*** Created by Javen on 2018/8/24.*/
public class PropertiesDemo {public static void main(String args[]) {writePropertiesFile(); //写 Properties 文件readPropertiesFile(); //读 Properties 文件}public static void writePropertiesFile() {File file &＃61; new File("D:" &＃43; File.separator &＃43; "PropertiesDemoWrite.txt");File file2 &＃61; new File("D:" &＃43; File.separator &＃43; "PropertiesDemoWriteXml.txt");Properties properties &＃61; new Properties();properties.setProperty("javen", "19950601");properties.setProperty("nanshen", "19960101");properties.setProperty("kunshen", "19940101");properties.setProperty("zuqiang", "19940201");try {properties.store(new FileOutputStream(file), "PropertiesDemo");//写文件properties.storeToXML(new FileOutputStream(file2), "PropertiesDemoXml", "utf-8");} catch (IOException e) {e.printStackTrace();}}public static void readPropertiesFile() {File file &＃61; new File("D:" &＃43; File.separator &＃43; "PropertiesDemoWrite.txt");File file2 &＃61; new File("D:" &＃43; File.separator &＃43; "PropertiesDemoWriteXml.txt");Properties properties &＃61; new Properties();Properties properties2 &＃61; new Properties();try {properties.load(new FileInputStream(file));properties2.loadFromXML(new FileInputStream(file2));} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}String jw &＃61; properties.getProperty("javen");String ns &＃61; properties.getProperty("nanshen");String zq &＃61; properties.getProperty("gangge");//不存在的keyString ks &＃61; properties.getProperty("kunshen");System.out.println( jw &＃43; "\n" &＃43; ns &＃43; "\n" &＃43; zq &＃43; "\n" &＃43; ks);}
}