定义了一个类，saveToRom函数将指定的数据写入tel.txt文件，loadFromRom从tel.txt文件读取数据

import android.content.Context;
 
import java.io.FileInputStream;
import java.io.FileOutputStream;
 
/**
 * Created by test on 2014/9/12.
 */
public class SaveDataService {
 
    //定义应用程序的上下文
    private Context context;
 
    //构造函数
    public SaveDataService(Context context){
        this.setContext(context);
    }
 
    private void setContext(Context context){
        this.context = context;
    }
 
    /*
    写入文件到rom
     */
    public void saveToRom(String tel,String content){
        try {
            FileOutputStream fos =  context.openFileOutput("tel.txt", Context.MODE_PRIVATE);
            String data = tel +":" + content;
            fos.write(data.getBytes());
            fos.flush();
            fos.close();
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }
 
    public String loadFromRom(){
        String result = "";
        try {
            StringBuffer sb = new StringBuffer();
            FileInputStream fis =  context.openFileInput("tel.txt");
            int ch;
            while((ch=fis.read()) !=-1) {
                sb.append((char)ch);
            }
            fis.close();
            result = sb.toString();
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
        return result;
    }
}