android java 文件的读写（转）

package xiaohang.zhimeng;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import org.apache.http.util.EncodingUtils;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.widget.TextView;

public class Activity01 extends Activity{
    //常量，为编码格式
    public static final String ENCODING = "UTF-8";
    //定义文件的名称
    String fileName = "test.txt";
    //写入和读出的数据信息
    String message = "欢迎大家来我们群里讨论问题";
    TextView textView;
     @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        writeFileData(fileName, message);
        String result = readFileData(fileName);
        textView = (TextView)findViewById(R.id.tv);
        textView.setTextColor(Color.GREEN);
        textView.setTextSize(20.0f);
        textView.setText(result);

    }
     //向指定的文件中写入指定的数据
     public void writeFileData(String filename, String message){
         try {
            FileOutputStream fout = openFileOutput(filename, MODE_PRIVATE);//获得FileOutputStream
            //将要写入的字符串转换为byte数组
            byte[]  bytes = message.getBytes();
            fout.write(bytes);//将byte数组写入文件
            fout.close();//关闭文件输出流
        } catch (Exception e) {
            e.printStackTrace();
        }
     }

     //打开指定文件，读取其数据，返回字符串对象
     public String readFileData(String fileName){
         String result="";
         try {
            FileInputStream fin = openFileInput(fileName);
            //获取文件长度
            int lenght = fin.available();
            byte[] buffer = new byte[lenght];
            fin.read(buffer);
            //将byte数组转换成指定格式的字符串
            result = EncodingUtils.getString(buffer, ENCODING);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
     }
}