sd卡文件存储和读取

package com.example.filedemo1;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;

import android.os.Bundle;
import android.app.Activity;

public class MainActivity extends Activity {
private static final String FILENAME = "/mnt/sdcard/neusoft/jmz.txt";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
File file = new File(FILENAME);
//判断文件是否存在，如果不存在创建
if(!file.getParentFile().exists()){
file.getParentFile().mkdirs();
}
PrintStream out = null;
try {
out = new PrintStream(new FileOutputStream(file));
out.println("中国吉林长春");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
if(out!=null){
out.close();
}
}
}

}

tv = (TextView) findViewById(R.id.tv);
// 判断sd卡是否挂载
if (Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED)) {
// 得到sd卡名称
File file = new File(Environment.getExternalStorageDirectory()
+ File.separator + DIR + File.separator + FILENAME);
Scanner sc = null;
try {
//判断文件是否存在
if (file.getParentFile().exists()) {
sc = new Scanner(new FileInputStream(file));
while (sc.hasNext()) {
tv.append(sc.next());
}
}else{
Toast.makeText(this, "不存在", 0).show();
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
if (sc != null) {
sc.close();
}
}

} else {
Toast.makeText(this, "不存在sd卡", 0).show();
}