并从AsyncTask的返回它

并从AsyncTask的返回它

本文介绍了从FTP服务器读取txt文件,并从AsyncTask的返回它的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我有一个 txt文件在我的 FTP服务器。和所有我想要做的就是读取文件,检索的内容,并通过使用的AsyncTask 保存为一个字符串。当我从logcat的理解,我能够连接 FTP服务器,我可以改变目录。但我不能阅读文本文件的情况下,我不知道如何从我的的AsyncTask 类返回。

而这些是我的codeS:

MainActivity.java

 包com.example.ftpdenemeleri;进口android.os.Bundle;
进口android.support.v7.app.ActionBarActivity;公共类MainActivity扩展ActionBarActivity {@覆盖
保护无效的onCreate(捆绑savedInstanceState){    super.onCreate(savedInstanceState);
    的setContentView(R.layout.activity_main);    FtpAsync任务1 =新FtpAsync();
    task1.execute();    }
}

FtpAsync.java

 包com.example.ftpdenemeleri;进口java.io.BufferedInputStream中;
进口java.io.IOException异常;
进口的java.io.InputStream;进口org.apache.commons.net.ftp.FTPClient;
进口org.apache.commons.net.ftp.FTPCmd;
进口android.os.AsyncTask;公共类FtpAsync扩展的AsyncTask<太虚,太虚,字符串> {@覆盖
在preExecute保护无效(){
   super.on preExecute();
}@覆盖
保护字符串doInBackground(虚空...... PARAMS){
    // TODO自动生成方法存根    FTPClient ftpClient =新FTPClient();
    尝试{
        ftpClient.connect(主机名,21);        的System.out.println(ftpClient.getReplyString());
        ftpClient.sendCommand(FTPCmd.USER,用户);
        的System.out.println(ftpClient.getReplyString());
        ftpClient.sendCommand(FTPCmd.PASS,通);
        的System.out.println(ftpClient.getReplyString());
        ftpClient.sendCommand(FTPCmd.CWD,/家庭/网络/ bitirme);
        InputStream为=新的BufferedInputStream(ftpClient.retrieveFileStream(beaglesays.txt));
        的System.out.println(输入流已经打开。);      }赶上(IOException异常前){
        通信System.err.println(除息);
    }
    返回null;
}保护无效onPostExecute(){
        // TODO:检查this.exception
        // TODO:做一些配合饲料
    }
}


解决方案

有很多方法可以充分阅读的InputStream为一个字符串。一个最简单的是使用 IOUtils.toString() 从的。

因此​​,假设,这些变化将返回从表示字符串doInBackground() onPostExecute接受它()

I have a txt file in my ftp server. And all I want to do is reading that file, retrieve the contents and save it as a string by using AsyncTask. As I understand from the logcat, I'm able to connect ftp server and I can change directory. But I cannot read the context of the text file, and I don't know how to return it from the my AsyncTask class.

And these are my codes:

MainActivity.java

package com.example.ftpdenemeleri;

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

public class MainActivity extends ActionBarActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    FtpAsync task1 = new FtpAsync();
    task1.execute();

    }
}

FtpAsync.java

package com.example.ftpdenemeleri;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPCmd;
import android.os.AsyncTask;

public class FtpAsync extends AsyncTask <Void, Void, String>{

@Override
protected void onPreExecute() {
   super.onPreExecute();
}

@Override
protected String doInBackground(Void... params) {
    // TODO Auto-generated method stub

    FTPClient ftpClient = new FTPClient();
    try {
        ftpClient.connect("hostname", 21);

        System.out.println(ftpClient.getReplyString());
        ftpClient.sendCommand(FTPCmd.USER, "user");
        System.out.println(ftpClient.getReplyString());
        ftpClient.sendCommand(FTPCmd.PASS, "pass");
        System.out.println(ftpClient.getReplyString());
        ftpClient.sendCommand(FTPCmd.CWD, "/home/www/bitirme");
        InputStream is = new      BufferedInputStream(ftpClient.retrieveFileStream("beaglesays.txt"));
        System.out.println("Input Stream has opened.");

      } catch (IOException ex) {
        System.err.println(ex);
    }
    return null;
}

protected void onPostExecute() {
        // TODO: check this.exception
        // TODO: do something with the feed
    }
}
解决方案

There are many ways to fully read an InputStream into a String. The easiest one would be to use IOUtils.toString() from Apache Commons IO.

So, assuming that, the changes would be to return said string from doInBackground() and receive it in onPostExecute().

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08-28 11:21