java.util.Properties工具类

import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Properties;

/**
 * @Description 加载属性配置文件工具类
 * @Package com.viathink.utils.PropertiesFilesUtils.java
 * @date 2012-5-16 下午3:18:19
 * @version V1.0
 */
public class PropertiesFilesUtils {
    private static final PropertiesFilesUtils propertiesFiles = new PropertiesFilesUtils();

    /**
     * 存放所有的属性配置文件对象
     */
    private Map<String, Properties> propertiesMap = new HashMap<String, Properties>();

    private PropertiesFilesUtils() {
    }

    /**
     * 获得属性配置文件工具类的实例对象
     * 
     * @return PropertiesFilesUtils 对象
     */
    public static PropertiesFilesUtils getInstance() {
        return propertiesFiles;
    }

    /**
     * 获取Properties文件对象
     * 
     * @param PropertiesFileName
     * @return
     * @throws IOException
     */
    public synchronized Properties getProperties(String propertiesFileName) throws IOException {
        if (propertiesFileName == null || "".equals(propertiesFileName)) {
            throw new IllegalArgumentException("The propertiesFileName is illegal argument!");
        }
        Properties prop = propertiesMap.get(propertiesFileName);
        if (prop == null) {
            prop = new Properties();
            //注意这个文件的InputStream，这里要修改
            InputStream is = this.getClass().getResourceAsStream(propertiesFileName);
            if (is == null)
                throw new FileNotFoundException("The file \"" + propertiesFileName + "\" is  not found!");
            prop.load(is);
            propertiesMap.put(propertiesFileName, prop);
        }
        return prop;
    }

    /**
     * 将properties文件写到磁盘上
     * 
     * @param properties
     *            属性文件
     * @param propertiesFilePath
     *            要保存的路径
     * @throws IOException
     */
    public void writePropertiesFile(Properties properties, String propertiesFilePath) throws IOException {
        if (properties == null || propertiesFilePath == null || "".equals(propertiesFilePath))
            throw new IllegalArgumentException("The props or propertiesFilePath  is illegal argument!");
        FileWriter fw = new FileWriter(propertiesFilePath);
        properties.store(fw, null);
        fw.flush();
        fw.close();
    }

    /**
     * 更新属性文件的某个属性,并保存到磁盘上
     * 
     * @param properties
     *            要更新的属性文件
     * @param propertyName
     *            属性名称
     * @param propertyValue
     *            属性值
     * @param filePath
     *            保存的文件路径
     * @throws IOException
     */
    public void updatePropertiesFile(Properties properties, String propertyName, String propertyValue, String filePath)
            throws IOException {
        if (properties == null || propertyName == null || "".equals(propertyName) || propertyValue == null
                || "".equals(propertyValue) || filePath == null || "".equals(filePath))
            throw new IllegalArgumentException("The parameters  is illegal argument!");
        properties.setProperty(propertyName, propertyValue);
        writePropertiesFile(properties, filePath);
    }

    /**
     * 根据属性配置文件名称和属性名称获取属性配置值
     * 
     * @param propertiesFileName
     *            属性配置文件名称
     * @param propertyName
     *            属性名称
     * @return 属性值
     * @throws IOException
     */
    public String getProperty(String propertiesFileName, String propertyName) throws IOException {
        Properties prop = getProperties(propertiesFileName);
        return prop.getProperty(propertyName);
    }

    /**
     * 获得Properties对象列表
     * 
     * @return
     */
    public List<Properties> getProperties() {
        if (propertiesMap.isEmpty())
            return null;
        return new LinkedList<Properties>(propertiesMap.values());
    }

    /**
     * 获得属性对象Map
     * 
     * @return
     */
    public Map<String, Properties> getPropertiesMap() {
        return propertiesMap;
    }

    public static void main(String[] args) throws IOException {
        String realPath="p.txt";
        PropertiesFilesUtils pfu = PropertiesFilesUtils.getInstance();
        Properties pro = pfu.getProperties(realPath);
        Properties pro1 = pfu.getProperties(realPath);
        Properties pro2 = pfu.getProperties(realPath);
        Properties pro3 = pfu.getProperties(realPath);
        
        System.out.println(pro == pro1);
        System.out.println(pro == pro2);
        System.out.println(pro == pro3);
        
        System.out.println(pfu.getProperties().size());
        System.out.println(pfu.getPropertiesMap().size());
        System.out.println(pro.getProperty("a"));
        pfu.updatePropertiesFile(pro, "messge.type", "image", realPath);
        System.out.println(pro.getProperty("messge.type"));
    }
}