android 超輕量級數據存儲類

    import java.io.File;

    import java.io.FileInputStream;

    import java.io.FileNotFoundException;

    import java.io.FileOutputStream;

    import java.io.IOException;

    import java.io.OutputStream;

    import java.io.UnsupportedEncodingException;

    import java.net.URLDecoder;

    import java.net.URLEncoder;

    import java.util.HashMap;

    import java.util.Map;

    import java.util.Properties;

    import java.util.Set;


import android.content.Context;  

/** 
 * android本地存儲 ，主要用于存儲簡單key value鍵值對。提供增、刪、改、查方法。 可自定義路徑 
 *  
 * @author Administrator 
 * 
 */  
public class LocalStorage {  
    private static Properties properties = new Properties();  
    private static String filepath;  

    private LocalStorage() {  
    }  

    /** 
     *  
     * @param ctx 
     * @param fileName 
     *            文件名 
     * @return 
     */  
    public static LocalStorage get(Context ctx, String fileName) {  
        return get(ctx.getCacheDir() + "/" + fileName);  
    }  

    /** 
     *  
     * @param filePath 
     *            文件絕對路徑 
     * @return 
     */  
    public static LocalStorage get(String filePath) {  
        createFile(filePath);  
        filepath = filePath;  
        try {  
            properties.load(new FileInputStream(filepath));  
            return new LocalStorage();  
        } catch (FileNotFoundException e) {  
            e.printStackTrace();  
        } catch (IOException e) {  
            e.printStackTrace();  
        }  
        return null;  
    }  

    private static void createFile(String fileName) {  
        File file = new File(fileName);  
        if (!file.exists()) {  
            String path = file.getAbsolutePath();  
            String[] sourceStrArray = path.split("/");  
            String dirPath = "";  
            for (int i = 0; i < sourceStrArray.length - 1; i++) {  
                if (!sourceStrArray[i].equals("")) {  
                    dirPath += "/" + sourceStrArray[i];  
                }  
            }  
            new File(dirPath).mkdirs();  
            try {  
                file.createNewFile();  
            } catch (IOException e) {  
                e.printStackTrace();  
            }  
        }  

    }  

    public String getAsString(String key) {  
        if (key == null) {  
            return null;  
        }  
        Properties props = new Properties();  
        try {  
            props.load(new FileInputStream(filepath));  
            String value = props.getProperty(key);  
            value = URLDecoder.decode(value, "utf-8");  
            return value;  
        } catch (Exception e) {  
            e.printStackTrace();  
            return null;  
        }  
    }  

    public int getAsInt(String key) {  
        String str = getAsString(key);  
        if (str == null)  
            return -9999;  
        return Integer.valueOf(str).intValue();  
    }  

    public boolean getAsBoolean(String key) {  
        String str = getAsString(key);  
        if (str == null)  
            return false;  
        if (str.equals("true"))  
            return true;  
        return false;  
    }  

    public long getAsLong(String key) {  
        String str = getAsString(key);  
        if (str == null)  
            return -9999;  
        return Long.valueOf(str).longValue();  
    }  

    public float getAsFloat(String key) {  
        String str = getAsString(key);  
        if (str == null)  
            return -9999;  
        return Float.valueOf(str).floatValue();  
    }  

    public double getAsDouble(String key) {  
        String str = getAsString(key);  
        if (str == null)  
            return -9999;  
        return Double.valueOf(str).doubleValue();  
    }  

    /** 
     * 添加 
     *  
     * @param keyname 
     * @param keyvalue 
     */  
    public void put(String keyname, Object keyvalue) {  
        // 處理中文亂碼  
        String value = keyvalue.toString();  
        try {  
            value = URLEncoder.encode(value, "utf-8");  
        } catch (UnsupportedEncodingException e1) {  
            e1.printStackTrace();  
        }  
        try {  
            OutputStream fos = new FileOutputStream(filepath);  
            properties.setProperty(keyname, value);  
            properties.store(fos, null);  
        } catch (IOException e) {  
        }  
    }  

    /** 
     * 更新 
     *  
     * @param keyname 
     * @param keyvalue 
     */  
    public void update(String keyname, String keyvalue) {  
        try {  
            properties.load(new FileInputStream(filepath));  
            OutputStream fos = new FileOutputStream(filepath);  
            properties.setProperty(keyname, keyvalue);  
            properties.store(fos, null);  
        } catch (IOException e) {  
        }  
    }  

    /** 
     * 根據key刪除 
     *  
     * @param key 
     */  
    public void delete(String key) {  
        try {  
            FileInputStream fis = new FileInputStream(filepath);  
            properties.load(fis);  
            Map<String, String> map = new HashMap<String, String>();  
            Set<Object> keySet = properties.keySet();  
            for (Object object : keySet) {  
                String objectkey = (String) object;  
                String value = (String) properties.get(objectkey);  
                map.put(objectkey, value);  
            }  
            map.remove(key);  
            properties.remove(key);  
            for (java.util.Map.Entry<String, String> entry : map.entrySet()) {  
                properties.setProperty(entry.getKey(), entry.getValue());  
            }  
            FileOutputStream fos = new FileOutputStream(filepath);  
            properties.store(fos, "delete key:" + key);  
            fos.close();  
            fis.close();  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
    }  
}  </pre> 



 
 使用方法 
 
    // 這里獲取LocalStorage對象。參數也可以為文件絕對路徑，當然也可以直接傳入Context和文件名。  
        LocalStorage localStorage = LocalStorage.get("test.txt");  
        // 增加  
        localStorage.put("key", "哈哈");  
        // 更新  
        localStorage.update("key", "value");  
        // 查找，這里提供多個getAs 方法。取數據找到相應的數據類型  
        localStorage.getAsString("key");  

        // 刪除  
        localStorage.delete("key");