修改配置不用重启服务的一种配置文件读取方式

来源：互联网发布：极米投影仪怎么样知乎编辑：程序博客网时间：2024/05/16 12:18

import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;import java.util.Properties;/** * 加载socket配置文件. *  */public final class LoadConfigUtil {/** * 属性文件全名"config/XXXX.properties". */private static final String PFILE = "config/test.properties";/** * 配置文件. */private Properties properties = null;/** * 对应属性文件. */private File file = null;/** * 属性最后修改日期. */private long lastModifiedTime = 0;/** *单例. */private static LoadConfigUtil instance = new LoadConfigUtil();/** * 私有构造方法. */private LoadConfigUtil() {file = new File(PFILE);lastModifiedTime = file.lastModified();if (lastModifiedTime == 0) {System.err.println(PFILE + "配置文件不存在");}try {properties = new Properties();properties.load(new FileInputStream(PFILE));} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}/** * 获得单例. *  * @return instance. */public static synchronized LoadConfigUtil getInstance() {return instance;}/** * 获得文件属性. *  * @param name *            参数名. * @param defaultVal *            默认值. * @return 属性值. */public String getConfigItem(String name, String defaultVal) {long newTime = file.lastModified();System.out.println("newtime:" + newTime);System.out.println("lastime:" + lastModifiedTime);// 检查属性文件是否被修改 ture则重新读取文件if (newTime == 0) {if (lastModifiedTime == 0) {System.err.println(PFILE + "配置文件不存在");} else {System.err.println(PFILE + "配置文件被删除");}return defaultVal;} else if (newTime > lastModifiedTime) {properties.clear();try {properties.load(new FileInputStream(PFILE));lastModifiedTime = newTime;} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}String val = properties.getProperty(name);if (val == null) {return defaultVal;} else {return val;}}public String getXxx() {return getConfigItem("xxx", "");}public static void main(String[] args) throws InterruptedException {String result = LoadConfigUtil.getInstance().getXxx();System.out.println(result);Thread.sleep(10000);result = LoadConfigUtil.getInstance().getXxx();System.out.println(result);}}

演示，在程序休眠期间，修改配置文件，即可得到新结果

newtime:1386732846531lastime:13867328465316newtime:1386931021114lastime:13867328465317

0 0