如何将字符串写入txt文件并将其发送到服务器

Question

我想在android中开发一个应用程序，我需要捕获图像并将该图像转换为字符串并将该字符串写入txt文件并将其发送到服务器，服务器读取该文件并再次将该字符串转换为图像…

现在我已经完成了图像的一部分，并将该图像转换为字符串并将该字符串写入TXT文件。

但是当我尝试读取该文件并将该字符串转换为图像时，它不起作用…

将图像转换为字符串的代码为

File imageFile = new File(path);
Bitmap bitmap = BitmapFactory.decodeFile(imageFile.getAbsolutePath());
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 90, stream);
byte[] image = stream.toByteArray();
imgstr = Base64.encodeToString(image, 0);   

将其写入文件的代码为

File file = new File("new.txt");
FileWriter w = new FileWriter("/sdcard/new/new.txt");
BufferedWriter out = new BufferedWriter(w);
out.write(data);
out.flush();
out.close();

读取文件并将字符串转换为图像的代码是

FileInputStream fstream = new FileInputStream("/sdcard/new/new.txt");          
DataInputStream in = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String strLine;
ArrayList list=new ArrayList();
while ((strLine = br.readLine()) != null)
{
    list.add(strLine);
}
Iterator itr;
for (itr=list.iterator(); itr.hasNext(); )
{
    String str=itr.next().toString(); 
    StringBuffer sb=new StringBuffer(str);
    int length=sb.length();
    String imageDataString = sb.substring(0, length);
    byte[] decodedString = Base64.decode(imageDataString, Base64.DEFAULT);
    Bitmap decodedByte = BitmapFactory.decodeByteArray(decodedString, 0,decodedString.length); 
    FileOutputStream imageOutFile = new FileOutputStream("/sdcard/new/android.jpg");
    imageOutFile.write(decodedString);
    imageOutFile.close();
    System.out.println("File converted");

但它没有将字符串转换成图像

Answer 1

如果你所需要的是通过ftp从android上传文件到web服务器，这将做的技巧(从froyo - up工作-但你必须导入apache commons并在你的"src"文件夹中安装一个副本):

import java.io.FileInputStream;
import org.apache.commons.net.ftp.FTPClient;
import android.util.Log;
public class FtpFileUp implements Runnable {
    private final String TAG = "FTPfile";
    boolean flagFTPOK = false;
    String fileName, fileDirSubLocalName, fileDirSubRemoteName;
    String fileDirName = NavigationActivity.fileDirName;

    FtpFileUp (String fileNameIn, String fileDirSubLocalNameIn, String fileDirSubRemoteNameIn) {
        fileName = (String) fileNameIn;
        fileDirSubLocalName = (String) fileDirSubLocalNameIn;
        fileDirSubRemoteName = (String) fileDirSubRemoteNameIn;
    }
    FtpFileUp (String fileNameIn) {
        String fileDirSubNameIn = "";
        fileName = (String) fileNameIn;
        fileDirSubLocalName = (String) fileDirSubNameIn;
        fileDirSubRemoteName = (String) fileDirSubNameIn;
    }
    FtpFileUp (String fileNameIn, String fileDirSubNameIn) {
        fileName = (String) fileNameIn;
        fileDirSubLocalName = (String) fileDirSubNameIn;
        fileDirSubRemoteName = (String) fileDirSubNameIn;
    }
    @Override
    public void run() {
        String ftpConnectString = "ftp.yourdomain.com";
        if (fileDirSubRemoteName != "") fileDirSubRemoteName += "/";
        if (fileDirSubLocalName != "") fileDirSubLocalName += "/";
        FTPClient ftpCli = new FTPClient();
        try {
           FileInputStream fis = new FileInputStream(fileDirName+"/"+fileDirSubLocalName+fileName);
           ftpCli.connect(ftpConnectString);
           ftpCli.login("user", "password");
           Log.i(TAG, "ok ftp "+ftpCli.getDataConnectionMode());
           ftpCli.storeFile("/"+fileDirSubRemoteName+fileName, fis);
           fis.close();
           flagFTPOK = true;
        } catch (Exception except) {
           Log.i(TAG, "ftp up FAIL "+except);
        }
    }
}

，您可以使用以下代码(由TRY CATCH封装)调用

Thread ftpThread01 = new Thread(new FtpFileUp("fileName", "", "/www/android/imgUpload"));
ftpThread01.start();

注意:正如你所看到的，有两个可选的构造函数，你可以使用它们来自动存储默认位置。它们可以被移除而不会造成任何伤害。