Android 读写文件

package pw.pw11.writetext;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;


public class MainActivity extends AppCompatActivity {
    private String path;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        path = getInnerSDCardPath();
        WriteText(path,"test.txt","太好了真棒，你是谁？",false);
    }
    @Override
    protected void onDestroy() {
        super.onDestroy();
        android.util.Log.d("TAG",ReadText(path,"test.txt"));
    }
    public String getInnerSDCardPath() {
        return android.os.Environment.getExternalStorageDirectory().getPath();
    }
    public void WriteText(String path,String filename,String content,boolean append){
        java.io.FileOutputStream fos=null;
        try {
            java.io.File file = new java.io.File(path+"/"+filename);
            fos = new java.io.FileOutputStream(file,append);
            fos.write(content.getBytes());
        } catch (java.io.IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (fos != null) {
                    fos.close();
                }
            } catch (java.io.IOException e) {
                e.printStackTrace();
            }
        }
    }
    public String ReadText(String path,String filename){
        java.io.FileInputStream fis=null;
        String result="";
        try{
            java.io.File file = new java.io.File(path+"/"+filename);
            fis = new java.io.FileInputStream(file);
            int length = fis.available();
            byte [] buffer = new byte[length];
            fis.read(buffer);
            result = new String(buffer,"UTF-8");
        }catch(java.io.IOException e) {
            e.printStackTrace();
        } finally{
            try {
                if (fis != null) {
                    fis.close();
                }
            } catch (java.io.IOException e) {
                e.printStackTrace();
            }
        }
        return result;
    }
}