Android数据持久化之File机制分析

package com.example.data_file;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStreamReader;import android.os.Bundle;import android.annotation.SuppressLint;import android.app.Activity;import android.util.Log;import android.view.Menu;@SuppressLint("SdCardPath")public class MainActivity extends Activity {  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    try {      File file = new File("/data/data/com.example.data_file/file.txt");      Log.v("path=", file.getAbsolutePath());      file.createNewFile();      FileOutputStream fos = new FileOutputStream(file);      fos.write("乌拉啦啦啦".getBytes());      fos.close();      FileInputStream fis = new FileInputStream(file);      InputStreamReader isReader = new InputStreamReader(fis);      char[] charArray = new char[2];      int readLength = isReader.read(charArray);      StringBuffer sb = new StringBuffer();      while(readLength != -1)      {        sb.append(charArray, 0, readLength);        readLength = isReader.read(charArray);      }      Log.v("file.txt文件内容是：", sb.toString());      fis.close();    } catch (IOException e) {      // TODO Auto-generated catch block      e.printStackTrace();    }  }  @Override  public boolean onCreateOptionsMenu(Menu menu) {    // Inflate the menu; this adds items to the action bar if it is present.    getMenuInflater().inflate(R.menu.main, menu);    return true;  }}