封装类：
package com.example.testsave.util; import java.io.BufferedReader; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.InputStreamReader; import android.content.Context; import android.os.Environment; import android.util.Log; import android.widget.Toast; public class SaveUtil { /** * * @param filename * @param content * @throws Exception */ public static void saveToSDCard(String filename, String content) throws Exception { File file = new File(Environment.getExternalStorageDirectory(), filename);// 指定文件存储目录为SD卡，文件名 FileOutputStream outStream = new FileOutputStream(file);// 输出文件流 outStream.write(content.getBytes()); outStream.close(); //如果没有a.txt会自动创建 加入true 会每次都追加 不加的话 则直接是新的文件 把a.txt替换掉 // File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath(), "a.txt"); // FileOutputStream fos = new FileOutputStream(file, true); // fos.write("这个是存储数据".getBytes()); // //这个地方并没有必要调用这个刷新方法 因为close也自带close 但是要养成好习惯 // fos.flush(); // fos.close(); } /** * * @param context * @return true 存在 false 不存在 */ public static boolean isExist(Context context) { boolean isExist = false; try { // 判断SDCard是否存在，并且可以读写 if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) { Toast.makeText(context, "yes", 1).show(); isExist = true; } else { Toast.makeText(context, "no", 1).show(); isExist = false; } } catch (Exception e) { Toast.makeText(context, "no", 1).show(); e.printStackTrace(); } return isExist; } /** * * @param file * @throws Exception */ public static void getToSDDate(String fileName) throws Exception{ File file = new File(Environment.getExternalStorageDirectory(), fileName); FileInputStream fis = new FileInputStream(file); BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(fis)); String s = bufferedReader.readLine(); //这个地方会显示这个是存储数据 Log.e("MainActivity", s); fis.close(); } }调用：
package com.example.testsave; import com.example.testsave.util.SaveUtil; import android.app.Activity; import android.os.Bundle; public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); boolean exist = SaveUtil.isExist(getApplicationContext()); if (exist) { try { SaveUtil.saveToSDCard("1.txt", "test"); // 保存数据 } catch (Exception e) { e.printStackTrace(); } } try { SaveUtil.getToSDDate("1.txt"); // 根据名称获取保存的数据 } catch (Exception e) { e.printStackTrace(); } // Log.e("MainActivity", localUrl); } }网络下载文件的保存： http://blog.csdn.net/pengyu1801/article/details/50085909
http://blog.csdn.net/pengyu1801/article/details/50085761
