properties类及其子类用法

来源：互联网发布：vb简单程序编写编辑：程序博客网时间：2024/05/29 18:07
在读取系统属性，环境变量，properties文件，简单的xml文件中，我们经常使用properties类

package demo4;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.FilterOutputStream;import java.io.IOException;import java.util.Enumeration;import java.util.InvalidPropertiesFormatException;import java.util.Map;import java.util.Map.Entry;import java.util.Properties;public class Test1 {/*读取环境变量*/public void environment(){Map<String,String> env=System.getenv();for(Entry<String, String> entry:env.entrySet()){System.out.println("key:"+entry.getKey()+"\t");System.out.println("value:"+entry.getValue()+"\n");}System.out.println("value:"+System.getenv("JAVA_HOME"));}/*读取系统属性*/public void systemProperty(){Properties prop = System.getProperties();// 列出全部系统属性内容for (Entry<Object, Object> entry : prop.entrySet()) {System.out.print("KEY: " + entry.getKey() + "\t");System.out.println("VALUE: " + entry.getValue());}// prop.list(System.out); // 该方法也可以列出全部系统属性// 获得指定系统属性内容String version = prop.getProperty("java.version");System.out.println(version);String dir = prop.getProperty("user.dir");System.out.println("dir="+dir);// 设置系统属性setProperty("mykey", "myvalue");System.out.println(prop.getProperty("mykey", "default"));// 列出全部系统属性名Enumeration<String> names = (Enumeration<String>) prop.propertyNames();while (names.hasMoreElements()) {String s = names.nextElement();System.out.println(s);}}private static void setProperty(String key, String value) {Properties prop = System.getProperties();prop.setProperty(key, value);}/*读取 properties文件*/public void propertyFile() throws FileNotFoundException, IOException{Properties prop=new Properties();File input=new File("test1.properties");prop.load(new FileInputStream(input));//prop.load(new FileReader(input));System.out.println(prop.getProperty("key1"));File output=new File("test2.properties");prop.setProperty("czk","123");prop.store(new FileOutputStream(output), "first record");// prop.store(new FileWriter(output), "属性列表的描述");}/*只能读取简单的xml文件*/public void xmlFile() throws InvalidPropertiesFormatException, FileNotFoundException, IOException{Properties prop = new Properties();File input = new File("config.xml");prop.loadFromXML(new FileInputStream(input));prop.setProperty("key", "value");File output = new File("new.xml");prop.storeToXML(new FileOutputStream(output), "属性列表的描述");}}
0 0