Android文件缓存 Json文件的读写

<span style="color:#333300;">package com.jingchen.tbviewer.utils;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.StreamCorruptedException;
import java.nio.channels.FileChannel;
import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import android.os.Environment;

public class CacheUtils {

	private static File CacheRoot;

	/**
	 * 存储Json文件
	 * 
	 * @param context
	 * @param json
	 *            json字符串
	 * @param fileName
	 *            存储的文件名
	 * @param append
	 *            true 增加到文件末，false则覆盖掉原来的文件
	 */
	public static void writeJson(Context c, String json, String fileName,
			boolean append) {

		CacheRoot = Environment.getExternalStorageState() == Environment.MEDIA_MOUNTED ? c
				.getExternalCacheDir() : c.getCacheDir();
		FileOutputStream fos = null;
		ObjectOutputStream os = null;
		try {
			File ff = new File(CacheRoot, fileName);
			boolean boo = ff.exists();
			fos = new FileOutputStream(ff, append);
			os = new ObjectOutputStream(fos);
			if (append && boo) {
				FileChannel fc = fos.getChannel();
				fc.truncate(fc.position() - 4);

			}

			os.writeObject(json);

		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {

			if (fos != null) {
				try {
					fos.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}

			}
			if (os != null) {

				try {
					os.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}

		}

	}

	/**
	 * 读取json数据
	 * 
	 * @param c
	 * @param fileName
	 * @return 返回值为list
	 */

	@SuppressWarnings("resource")
	public static List<String> readJson(Context c, String fileName) {

		CacheRoot = Environment.getExternalStorageState() == Environment.MEDIA_MOUNTED ? c
				.getExternalCacheDir() : c.getCacheDir();
		FileInputStream fis = null;
		ObjectInputStream ois = null;
		List<String> result = new ArrayList<String>();
		File des = new File(CacheRoot, fileName);
		try {
			fis = new FileInputStream(des);
			ois = new ObjectInputStream(fis);
			while (fis.available() > 0)
				result.add((String) ois.readObject());

		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (StreamCorruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			if (fis != null) {
				try {
					fis.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}

			if (ois != null) {
				try {
					ois.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}

		}

		return result;
	}

}</span><strong style="color: rgb(255, 0, 0);">
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