Android sdcard读写文件（二）

继续说sdcard读写文件的情况，这篇博客说的是在sdcard根目录中读写文件，着重的而是多种方式的读写文件。直接给出代码：

FileService.java

package com.llp.classdifine;import java.io.BufferedWriter;import java.io.ByteArrayOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.OutputStreamWriter;import android.content.Context;import android.os.Environment;public class FileService {private Context context;private String mPath = Environment.getExternalStorageDirectory().getPath()+ "/datas";public FileService(Context context) {this.context = context;}/** * 保存内容到sd卡中（以私有文件形式保存） *  * @param filename *            文件名称 * @param content *            文件内容 * @throws Exception */public void save2sdCard(String fileName, String content) throws Exception {File file = new File(Environment.getExternalStorageDirectory(),fileName);FileOutputStream outputStream = new FileOutputStream(file);outputStream.write(content.getBytes());outputStream.close();}/** * 保存内容（以私有文件形式保存） *  * @param filename *            文件名称 * @param content *            文件内容 * @throws Exception */public void save(String fileName, String content) throws Exception {FileOutputStream outputStream = context.openFileOutput(fileName,Context.MODE_PRIVATE);outputStream.write(content.getBytes());outputStream.close();}/** * 保存内容（以私有文件形式保存+追加） *  * @param filename *            文件名称 * @param content *            文件内容 * @throws Exception */public void saveAppend(String fileName, String content) throws Exception {FileOutputStream outputStream = context.openFileOutput(fileName,Context.MODE_APPEND);outputStream.write(content.getBytes());outputStream.close();}/** * 保存内容（允许其他应用读取） *  * @param filename *            文件名称 * @param content *            文件内容 * @throws Exception */public void saveReadAble(String fileName, String content) throws Exception {FileOutputStream outputStream = context.openFileOutput(fileName,Context.MODE_WORLD_READABLE);outputStream.write(content.getBytes());outputStream.close();}/** * 保存文件到sdcard中某个路径下 * @param fileName * @param content */public void write2Path(String fileName, String content) {File f = new File(mPath + "/" + fileName + ".txt");try {FileOutputStream fileOS = new FileOutputStream(f);try {fileOS.write(content.getBytes());fileOS.close();BufferedWriter buf = new BufferedWriter(new OutputStreamWriter(fileOS));buf.write(content, 0, content.length());buf.flush();buf.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();}}/** * 从sdcard中的某个路径下读取文件 * @param fileName * @return */public String readFromPath(String fileName) {byte[] data = new byte[1024];try {FileInputStream fileIS = new FileInputStream(mPath + "/" + fileName+ ".txt");// BufferedReader buf = new BufferedReader(new// InputStreamReader(in))byte[] buffer = new byte[1024];ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();int len = -1;while ((len = fileIS.read(buffer)) != -1) {// 读取文件到缓冲区byteArrayOutputStream.write(buffer, 0, len);// 写入到内存}data = byteArrayOutputStream.toByteArray();// 将内存中的二进制数据转为数组byteArrayOutputStream.close();fileIS.close();} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}return new String(data);}/** * 文件读取 *  * @param fileName * @return * @throws Exception */public String read(String fileName) throws Exception {FileInputStream inputStream = context.openFileInput(fileName);byte[] buffer = new byte[1024];ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();int len = -1;while ((len = inputStream.read(buffer)) != -1) {// 读取文件到缓冲区byteArrayOutputStream.write(buffer, 0, len);// 写入到内存}byte[] data = byteArrayOutputStream.toByteArray();// 将内存中的二进制数据转为数组byteArrayOutputStream.close();inputStream.close();return new String(data);}}

MainActivity.java文件：

package com.example.sdcard;import java.io.File;import com.example.sdcard.FileService;import android.app.Activity;import android.os.Bundle;import android.os.Environment;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class MainActivity extends Activity {/** Called when the activity is first created. */private static final String TAG = "MainActivity";private FileService fileService;String fileName;String content;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);File sd = Environment.getExternalStorageDirectory();String mPath = sd.getPath() + "/datas";File file = new File(mPath);if (!file.exists()) {file.mkdir();}Log.v("test", "file.getPath()" + file.getPath());Button button = (Button) findViewById(R.id.btnsave);Button read = (Button) findViewById(R.id.btnread);fileService = new FileService(this);// File file = this.getFilesDir();// 快速得到文件夹// this.getCacheDir();// 获得缓存文件夹final EditText fileNameText = (EditText) findViewById(R.id.fileName);final EditText contenText = (EditText) findViewById(R.id.content);final EditText readtext = (EditText) findViewById(R.id.contentread);button.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {fileName = fileNameText.getText().toString();content = contenText.getText().toString();try {// 判断sd卡是否存在手机上并且可以进行读写if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {fileService.write2Path(fileName, content);} else {}} catch (Exception e) {Log.e(TAG, e.toString());}}});read.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubtry {// 判断sd卡是否存在手机上并且可以进行读写if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {fileName = fileNameText.getText().toString();Log.v("test", "fileName" + fileName);readtext.setText(fileService.readFromPath(fileName));} else {}} catch (Exception e) {Log.e(TAG, e.toString());}}});}}