android File 读取存储 saveTo sdcard

来源：互联网发布：cacti 监控windows 编辑：程序博客网时间：2024/05/28 16:24

package cn.itcast.service;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;

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

public class FileService {
   private Context context;

   public FileService(Context context) {
       this.context = context;
   }

   // 
   // <uses-permission
   // android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
   // 
   // <uses-permission
   // android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
   public void saveToSDCard(String filename, String content) throws Exception {
       //File file=new File("/mnt/sdcard",filename); 但是不建议这么写因为可能因为版本的不同而变化;
       File file = new File(Environment.getExternalStorageDirectory(),
               filename);
       FileOutputStream outStream = new FileOutputStream(file);
       outStream.write(content.getBytes());
       outStream.close();
   }

   /**
   * 保存文件
   *
   * @param filename
   *            文件名称
   * @param content
   *            文件内容
   */
   public void save(String filename, String content) throws Exception {
       // 私有操作模式：创建出来的文件只能被本应用访问，其它应用无法访问该文件，另外采用私有操作模式创建的文件，写入文件中的内容会覆盖原文件的内容
       FileOutputStream outStream = context.openFileOutput(filename,
               Context.MODE_PRIVATE);
       outStream.write(content.getBytes());
       outStream.close();
   }

   /**
   * 保存文件
   *
   * @param filename
   *            文件名称
   * @param content
   *            文件内容
   */
   public void saveAppend(String filename, String content) throws Exception {// ctrl+shift+y//
                                                                               // x
       // Context.Mode_APPEND:和私有一样只能被本应用访问;不同点检查文件是否存在; 存在就追加到原文件中;
       FileOutputStream outStream = context.openFileOutput(filename,
               Context.MODE_APPEND);
       // content.getBytes(String encoding); 会使用和系统指定的字符集编码; 如果没有指定会使用iso8859-1;
       outStream.write(content.getBytes());
       outStream.close();
   }

   /**
   * 保存文件
   *
   * @param filename
   *            文件名称
   * @param content
   *            文件内容
   */
   public void saveReadable(String filename, String content) throws Exception {
       // 私有操作模式：创建出来的文件只能被本应用访问，其它应用无法访问该文件，另外采用私有操作模式创建的文件，写入文件中的内容会覆盖原文件的内容
       FileOutputStream outStream = context.openFileOutput(filename,
               Context.MODE_WORLD_READABLE);
       outStream.write(content.getBytes());
       outStream.close();
   }

   /**
   * 保存文件
   *
   * @param filename
   *            文件名称
   * @param content
   *            文件内容
   */
   public void saveWriteable(String filename, String content) throws Exception {
       // writeable 文件不能被其他的读取; 但是能够被写入(自己感觉是覆盖里面的内容)
       FileOutputStream outStream = context.openFileOutput(filename,
               Context.MODE_WORLD_WRITEABLE);
       outStream.write(content.getBytes());
       outStream.close();
   }

   /**
   * 保存文件
   *
   * @param filename
   *            文件名称
   * @param content
   *            文件内容
   */
   public void saveRW(String filename, String content) throws Exception {
       // 如果希望文件被其他应用读和写; 可以传入
       // Context.MODE_WORLD_READABLE+Context.MODE_WORLD_WRITEABLE;
       // 默认的写的模式写模式是覆盖掉;如果想追加的话在fileoutputStream(file,true);
       // 就会追加了;
       FileOutputStream outStream = context.openFileOutput(filename,
               Context.MODE_WORLD_WRITEABLE + Context.MODE_WORLD_READABLE);
       outStream.write(content.getBytes());
       outStream.close();
   }

   /**
   * 读取文件内容
   *
   * @param filename
   *            文件名称
   * @return 文件内容
   * @throws Exception
   */
   public String read(String filename) throws Exception {
       FileInputStream inStream = context.openFileInput(filename);
       ByteArrayOutputStream outStream = new ByteArrayOutputStream();// 装进内存缓存流;
       byte[] buffer = new byte[1024];
       int len = 0;
       while ((len = inStream.read(buffer)) != -1) {
           outStream.write(buffer, 0, len);// 先读取到内存中;
       }
       byte[] data = outStream.toByteArray();//字节流的数组;
       return new String(data);
   }

}

//-----------------------------------------------本应用中的testCase -----AndroidTestCase-------------------------------------------------------

public class FileServiceTest extends AndroidTestCase {
   private static final String TAG = "FileServiceTest";

   public void testRead() throws Throwable{
       // 默认的是保存到手机存储空间; 在本应用中这里不用写路径;
       FileService service = new FileService(this.getContext());
       String result = service.read("itcast.txt");
       Log.i(TAG, result);
   }

   public void testSaveAppend() throws Throwable{

       FileService service = new FileService(this.getContext());
       service.saveAppend("append.txt", ",liming");
   }

//----------------------------------------------------------------------other 其他应用中访问本应用的文件的TestCase-----------------------------------------

package cn.itcast.test;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;

import android.test.AndroidTestCase;
import android.util.Log;

public class AccessOtherAppFileTest extends AndroidTestCase {

   private static String read(InputStream inStream) throws Exception{
       ByteArrayOutputStream outStream = new ByteArrayOutputStream();
       byte[] buffer = new byte[1024];
       int len = 0;
       while((len = inStream.read(buffer)) != -1){
           outStream.write(buffer, 0, len);
       }
       byte[] data = outStream.toByteArray();
       return new String(data);
   }

   public void testAccessFile() throws Throwable{
       String path = "/data/data/cn.itcast.files/files/itcast.txt";
       File file = new File(path);
       FileInputStream inStream = new FileInputStream(file);
       Log.i("AccessOtherAppFileTest", read(inStream));
   }

   public void testAccessFile2() throws Throwable{
       String path = "/data/data/cn.itcast.files/files/append.txt";
       File file = new File(path);
       FileInputStream inStream = new FileInputStream(file);
       Log.i("AccessOtherAppFileTest", read(inStream));
   }

   public void testAccessFile3() throws Throwable{
       String path = "/data/data/cn.itcast.files/files/readable.txt";
       File file = new File(path);
       FileInputStream inStream = new FileInputStream(file);
       Log.i("AccessOtherAppFileTest", read(inStream));
   }

   public void testAccessFile4() throws Throwable{
       String path = "/data/data/cn.itcast.files/files/writeable.txt";
       File file = new File(path);
       FileInputStream inStream = new FileInputStream(file);
       Log.i("AccessOtherAppFileTest", read(inStream));
   }

   public void testAccessFile5() throws Throwable{
       // 在访问别的项目的文件的时候需要指定路径;
       String path = "/data/data/cn.itcast.files/files/writeable.txt";
       File file = new File(path);
       FileOutputStream outStream = new FileOutputStream(file);
       outStream.write("itcast".getBytes());
       outStream.close();
   }

   public void testAccessFile7() throws Throwable{
       String path = "/data/data/cn.itcast.files/files/rw.txt";
       File file = new File(path);
       FileInputStream inStream = new FileInputStream(file);
       Log.i("AccessOtherAppFileTest", read(inStream));
   }

   public void testAccessFile8() throws Throwable{
       String path = "/data/data/cn.itcast.files/files/rw.txt";
       File file = new File(path);
       FileOutputStream outStream = new FileOutputStream(file,true);// 在fileout putStream 可以指定是否追加到文件末尾; 默认是覆盖;
       outStream.write("8888".getBytes());
       outStream.close();
   }
}