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java - Android ssh在Buttonclick上没有返回任何东西

问题描述

我最近制作了一个应用程序，当按下按钮时在我的电脑上执行一个小的 ssh 命令，但是当我运行它时似乎什么也没发生。我对 android 开发有点陌生 - 所以我不太确定我是否正确使用了 jsh。

我的主要活动如下：

package com.amex.myapplication;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import com.jcraft.jsch.ChannelExec;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.Session;
import java.io.ByteArrayOutputStream;
import java.util.Properties;

public class MainActivity extends AppCompatActivity {


public static String executeRemoteCommand(
        String username,
        String password,
        String hostname,
        int port) throws Exception {

    JSch jsch = new JSch();
    Session session = jsch.getSession("exiatron00", "192.168.0.10", 22);
    session.setPassword("password");

    // Avoid asking for key confirmation
    Properties prop = new Properties();
    prop.put("StrictHostKeyChecking", "no");
    session.setConfig(prop);

    session.connect();

    // SSH Channel
    ChannelExec channelssh = (ChannelExec) session.openChannel("exec");
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    channelssh.setOutputStream(baos);

    // Execute command
    channelssh.setCommand("touch /home/exiatron00/Desktop/sshtest.txt");
    channelssh.connect();
    channelssh.disconnect();

    return baos.toString();


}


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

}

public void Button(View view) {
    try {
        executeRemoteCommand("exiatron00", "NvidiaGtx1!", "192.168.1.10", 22);
    } catch (Exception e) {
        e.printStackTrace();
    }



 }
}

我的清单是：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
 package="com.amex.myapplication">
  <uses-permission android:name="android.permission.INTERNET"/>
<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
     </activity>
  </application>
</manifest>

但是当我按下按钮时没有任何反应，logcat 会返回：

2020-07-20 12:12:10.342 3461-3461/com.amex.myapplication V/AudioManager:    querySoundEffectsEnabled...
2020-07-20 12:12:10.346 3461-3461/com.amex.myapplication W/System.err:  com.jcraft.jsch.JSchException: android.os.NetworkOnMainThreadException
2020-07-20 12:12:10.346 3461-3461/com.amex.myapplication W/System.err:     at com.jcraft.jsch.Util.createSocket(Util.java:258)
2020-07-20 12:12:10.346 3461-3461/com.amex.myapplication W/System.err:     at com.jcraft.jsch.Session.connect(Session.java:186)
2020-07-20 12:12:10.346 3461-3461/com.amex.myapplication W/System.err:     at com.jcraft.jsch.Session.connect(Session.java:145)
2020-07-20 12:12:10.346 3461-3461/com.amex.myapplication W/System.err:     at com.amex.myapplication.MainActivity.executeRemoteCommand(MainActivity.java:29)
2020-07-20 12:12:10.346 3461-3461/com.amex.myapplication W/System.err:     at com.amex.myapplication.MainActivity.Button(MainActivity.java:56)
2020-07-20 12:12:10.346 3461-3461/com.amex.myapplication W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
2020-07-20 12:12:10.346 3461-3461/com.amex.myapplication W/System.err:     at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflat  er.java:397)
2020-07-20 12:12:10.346 3461-3461/com.amex.myapplication W/System.err:     at  android.view.View.performClick(View.java:7213)
2020-07-20 12:12:10.347 3461-3461/com.amex.myapplication W/System.err:     at android.view.View.performClickInternal(View.java:7187)
2020-07-20 12:12:10.347 3461-3461/com.amex.myapplication W/System.err:     at android.view.View.access$3500(View.java:828)
2020-07-20 12:12:10.347 3461-3461/com.amex.myapplication W/System.err:     at android.view.View$PerformClick.run(View.java:27675)
2020-07-20 12:12:10.347 3461-3461/com.amex.myapplication W/System.err:     at android.os.Handler.handleCallback(Handler.java:900)
2020-07-20 12:12:10.347 3461-3461/com.amex.myapplication W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:103)
2020-07-20 12:12:10.347 3461-3461/com.amex.myapplication W/System.err:     at android.os.Looper.loop(Looper.java:219)
2020-07-20 12:12:10.347 3461-3461/com.amex.myapplication W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:8347)
2020-07-20 12:12:10.347 3461-3461/com.amex.myapplication W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
2020-07-20 12:12:10.347 3461-3461/com.amex.myapplication W/System.err:     at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)
2020-07-20 12:12:10.347 3461-3461/com.amex.myapplication W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1055)
2020-07-20 12:12:10.347 3461-3461/com.amex.myapplication W/System.err: Caused by: android.os.NetworkOnMainThreadException
2020-07-20 12:12:10.347 3461-3461/com.amex.myapplication W/System.err:     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1565)
2020-07-20 12:12:10.347 3461-3461/com.amex.myapplication W/System.err:     at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:389)
2020-07-20 12:12:10.348 3461-3461/com.amex.myapplication W/System.err:     at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:230)
2020-07-20 12:12:10.348 3461-3461/com.amex.myapplication W/System.err:     at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:212)
2020-07-20 12:12:10.348 3461-3461/com.amex.myapplication W/System.err:     at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:436)
2020-07-20 12:12:10.348 3461-3461/com.amex.myapplication W/System.err:     at java.net.Socket.connect(Socket.java:621)
2020-07-20 12:12:10.348 3461-3461/com.amex.myapplication W/System.err:     at java.net.Socket.connect(Socket.java:570)
2020-07-20 12:12:10.348 3461-3461/com.amex.myapplication W/System.err:     at java.net.Socket.<init>(Socket.java:450)
2020-07-20 12:12:10.348 3461-3461/com.amex.myapplication W/System.err:     at java.net.Socket.<init>(Socket.java:218)
2020-07-20 12:12:10.348 3461-3461/com.amex.myapplication W/System.err:     at com.jcraft.jsch.Util.createSocket(Util.java:252)
2020-07-20 12:12:10.348 3461-3461/com.amex.myapplication W/System.err:  ... 17 more

标签： javaandroidandroid-studio

解决方案

问题：您试图在主/UI 线程上运行网络操作，这是 JSch 禁止的。

原因：主（UI）线程负责显示用户界面并处理用户与应用程序视觉元素的交互。网络操作，或任何其他可能需要很长时间才能执行的工作，可能会冻结 UI 线程并导致 ANR（Android Not Responding crash，当 UI 冻结一段时间时触发）。所以 JSch 通过检查它的执行线程来阻止它。您应该在另一个线程上执行您的操作。

您可以为此使用处理程序

private Handler mHandler;

private HandlerThread mHandlerThread;

public void startHandlerThread(){
    mHandlerThread = new HandlerThread("HandlerThread");
    mHandlerThread.start();
    mHandler = new Handler(mHandlerThread.getLooper());
}

// Then in your button method
mHandler.postDelayed(
    new Runnable() { 
        public void run() {
            executeRemoteCommand(yourParameters); 
        }
    }
);

或者您可以尝试使用 oldschool Java Thread 在另一个线程上运行它

Thread worker = new Thread(
    new Runnable() { 
        public void run() {
            executeRemoteCommand(yourParameters); 
        }
    }
);
worker.start();

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