用IO流向存储器或SD卡中存入/读取字符的工具类

FileManager

package com.kale.utils;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintStream;

import android.content.Context;
import android.os.Environment;

/**
 * @author:Jack Tony
 * @tips  :
 *  <!-- 读写SD卡的权限 -->
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 * @date  :2014-6-30
 */
public class FileManager {
    private String SD_PATH;
    private String fileName;
    private String dirName;

    public String getSD_PATH() {
        return SD_PATH;
    }
    
    /**
     * @param permission 是否添加了权限
     */
    public FileManager(boolean permission) {
        //得到当前外部存储设备的目录
        SD_PATH = Environment.getExternalStorageDirectory() + "/";
    }
    
    /**
     * 在SD卡上创建文件
     * 
     * @throws IOException
     */
    public File creatSDFile(String dirName ,String fileName) throws IOException {
        this.fileName = fileName;
        this.dirName = dirName;
        File file = new File(creatSDDir(dirName), fileName);
        return file;
    }
    
    
    public String getFileWholePath() throws IOException{
        if (dirName == null || fileName == null) {
            return SD_PATH + dirName + "/" + fileName;
        }
        else {
            throw new IOException("can't find dirName or fileName");
        }
        
    }
    
    /**
     * 在SD卡上创建目录
     * 
     * @param dirName
     */
    public File creatSDDir(String dirName) {
        File dir = new File(SD_PATH + dirName);
        dir.mkdir();
        return dir;
    }
    


    /**
     * 判断SD卡上的文件夹是否存在
     * kale,file.txt->kale/file.txt
     */
    public boolean isFileExist(String dirName ,String fileName){
        File file = new File(SD_PATH +dirName+"/"+ fileName);
        return file.exists();
    }
    
    /**
     * 将一个InputStream里面的数据写入到SD卡中
     * example：kale,file.txt,inputStream->kale/file.txt
     * InputStream is = new ByteArrayInputStream( "kale data".getBytes() );
       manager.saveToSdCard("dir02", "kale.txt", is );
     */
    public File saveToSDcard(String dirName,String fileName,InputStream input){
        File file = null;
        OutputStream output = null;
        try{
            //创建目录
            creatSDDir(dirName);
            //建立文件
            file = creatSDFile(dirName ,fileName);
            output = new FileOutputStream(file);
            byte buffer [] = new byte[5 * 1024];
            //int count = 0;
            while((input.read(buffer)) != -1){
                //String str = new String(buffer,0,count);
                //str = new String(str.getBytes("iso-8859-1"),"utf-8");                
                /*System.out.println("---------File Manager----start--------");
                System.out.println(str);
                System.out.println("---------File Manager-----end-------");*/
                output.write(buffer);
            }
            output.flush();
        }
        catch(Exception e){
            e.printStackTrace();
        }
        finally{
            try{
                output.close();
            }
            catch(Exception e){
                e.printStackTrace();
            }
        }
        return file;
    }
    
    /**
     * @param dirName
     * @param fileName
     * @return 从sd卡中读取文件的字符，返回String
     * @throws Exception
     */
    public String readFromSDcard(String dirName,String fileName) throws FileNotFoundException {
        try {
            File file = new File(SD_PATH +dirName+"/"+ fileName);
            FileInputStream fis = new FileInputStream(file);
            BufferedReader br = new BufferedReader(new InputStreamReader(fis));
            StringBuilder sb = new StringBuilder("");
            String line = null;
            //循环读取文件内容
            while((line = br.readLine()) != null) {
                sb.append(line);
            }
            br.close();
            return sb.toString().trim();
        } 
        catch(FileNotFoundException e) {
            e.printStackTrace();
            throw new FileNotFoundException("no such file");
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
    
    /////////////////////// 直接读取包名文件夹下的文件，而不是SD卡中的 /////////////////////
    /**
     * @param str
     * 将string写入到data/data/包名/files中
     * example:write(file.txt ,data)
     */
    public static void write(Context mContext,String fileName,String str) {
        try {
            /**
             * MODE_PRIVATE:该文件只能被当前程序读写 MODE_APPEND:用追加方式打开文件，新写入的内容追加到末尾
             * MODE_WORLD_READABLE:该文件内容可以被其他程序读
             * MODE_WORLD_WRITEABLE:该文件内容可以被其他程序读写
             */
            FileOutputStream fos = mContext.openFileOutput(fileName, Context.MODE_PRIVATE | Context.MODE_APPEND);
            PrintStream ps = new PrintStream(fos);
            // 输出文件的内容
            ps.println(str);
            ps.close();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 通过文件名来读取data/data/包名/files下的文件
     * example:read("file.txt")
     * @return 
     * 返回null，表示找不到文件，或出现异常
     */
    public static String read(Context mContext,String fileName) {
        try {
            // 打开文件输入流
            FileInputStream fis = mContext.openFileInput(fileName);
            byte[] buff = new byte[1024];
            int hasRead = 0;
            StringBuilder sb = new StringBuilder("");
            // 读取文件内容
            while ((hasRead = fis.read(buff)) > 0) {
                sb.append(new String(buff, 0, hasRead));
            }
            // 关闭文件输入流
            fis.close();
            return sb.toString();
        } 
        catch(FileNotFoundException e) {
            e.printStackTrace();
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

}