044_Properties工具类

Properties类详解

最新推荐文章于 2022-02-07 15:41:09 发布

原创最新推荐文章于 2022-02-07 15:41:09 发布 · 297 阅读

0 ·

CC 4.0 BY-SA版权

Java基础学习专栏收录该内容

51 篇文章

订阅专栏

本文详细介绍了Java中的Properties类，包括其继承关系、基本用途、推荐使用方法及如何通过各种方式加载和存储属性。同时提供了具体的代码示例来演示如何操作Properties对象。

1. Properties继承HashTable

public class Propertiesextends Hashtable<Object,Object>

2. Properties类表示了一个持久的属性集。Properties可保存在流中或从流中加载。属性列表中每个键及其对应值都是一个字符串。

3. 官方推荐使用setProperty方法, 不要使用put和putAll方法

4. load(Reader)/store(Writer, String)简单的面向行的格式在基于字符的流中加载和存储属性。除了输入/输出流使用ISO 8859-1字符编码外,

load(InputStream)/store(OutputStream, String)方法与load(Reader)/store(Writer, String)对的工作方式完全相同。

5. loadFromXML(InputStream)和storeToXML(OutputStream, String, String)方法按简单的XML格式加载和存储属性。默认使用UTF-8字符编码。

6. Properties是线程安全的, 多个线程可以共享单个Properties对象而无需进行外部同步。

7. 使用Properties工具类

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Properties;
import java.util.Set;

public class UseProperties {
	/**
	 * Properties的keys和loadFromXML方法加载数据
	 * @throws FileNotFoundException
	 * @throws IOException
	 */
	public void loadFromXML() throws FileNotFoundException, IOException {
		Properties properties = new Properties();
		properties.loadFromXML(new FileInputStream("middleware.xml"));
		
		Enumeration<Object> e = properties.keys();
		while(e.hasMoreElements()) {
			String key = (String) e.nextElement();
			System.out.println(key + ":" + properties.getProperty(key, ""));
		}
	}
	
	/**
	 * Properties的setProperty和storeToXML方法储存数据
	 * @throws FileNotFoundException
	 * @throws IOException
	 */
	public static void storeToXML() throws FileNotFoundException, IOException {
		Properties properties = new Properties();
		properties.setProperty("game", "unity");
		properties.setProperty("middleware", "c++");
		properties.setProperty("plantform1", "jni c++");
		properties.setProperty("plantform2", "oc c++");
		
		properties.storeToXML(new FileOutputStream("middleware.xml"), "game sdk middleware");
	}
	
	/**
	 * Properties的getProperty和load方法加载数据
	 * @throws FileNotFoundException
	 * @throws IOException
	 */
	public void load() throws FileNotFoundException, IOException {
		Properties properties = new Properties();
		properties.load(new FileInputStream("people.properties"));
		
		Set<Object> set = properties.keySet();
		for (Object object : set) {
			System.out.println(object + ":" + properties.getProperty((String)object, ""));
		}
	}
	
	/**
	 * Properties的setProperty和store方法储存数据
	 * @throws FileNotFoundException
	 * @throws IOException
	 */
	public void store() throws FileNotFoundException, IOException {
		Properties properties = new Properties();
		properties.setProperty("name", "zhangsan");
		properties.setProperty("age", "22");
		properties.setProperty("sex", "male");
		
		properties.store(new FileOutputStream("people.properties"), "people infomation");
	}
	
}