Question

我已经提供了简单的Web服务，您必须在其中提供您的姓名。它将返回“ Hello” +您的名字。

在服务器端

myWebService.java

package pkg;

import javax.jws.WebService;
import javax.jws.WebMethod;
import javax.jws.WebParam;


@WebService(serviceName = "myWebService")
public class myWebService {


    @WebMethod(operationName = "hello")
    public String hello(@WebParam(name = "name") String txt) {
        return "Hello " + txt + " !";
    }
}

在客户端

Index.jsp

<%@page import="java.io.Writer"%>
<%@page import="org.json.JSONObject"%>
<%@page import="org.json.JSONArray"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="application/json; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <form action="#">
            <input type="text" name="t1">
            <input type="submit" value="CLICK"><br>
        </form>
    </body>
</html>
    <%-- start web service invocation --%><hr/>
    <%
    try {
    pkg.MyWebService_Service service = new pkg.MyWebService_Service();
    pkg.MyWebService port = service.getMyWebServicePort();
    java.lang.String name = request.getParameter("t1");
    java.lang.String result = port.hello(name);

        out.write(result);

    } catch (Exception ex) 
    {

    }
    %>
    <%-- end web service invocation --%><hr/>

浏览器上的输出

因此，当我从浏览器调用Web Service时，它可以正常工作。但是当我尝试从Android调用它时会出现问题。

build.gradle（模块：应用）

apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    defaultConfig {
        applicationId "com.example.akshay.httpclientdemo"
        minSdkVersion 14
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    packagingOptions {
        exclude 'META-INF/DEPENDENCIES'
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/LICENSE.txt'
        exclude 'META-INF/license.txt'
        exclude 'META-INF/NOTICE'
        exclude 'META-INF/NOTICE.txt'
        exclude 'META-INF/notice.txt'
        exclude 'META-INF/ASL2.0'
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation files('libs/httpclient-4.5.9.jar')
    implementation files('libs/httpcore-4.4.11.jar')
}

AndroidManifest.xml

    <?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.example.akshay.httpclientdemo">

        <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>

**activity_main.xml**
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/t1"
        android:layout_width="293dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:ems="10"
        android:inputType="textPersonName"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/t2"
        android:layout_width="289dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:ems="10"
        android:inputType="textPersonName"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/t1" />

    <Button
        android:id="@+id/btn"
        android:layout_width="132dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="Button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/t2" />

    <ProgressBar
        android:id="@+id/pBar"
        style="?android:attr/progressBarStyle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity
{

    Button btn;
    EditText t1,t2;
    ProgressBar pBar;

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

        btn=(Button)findViewById(R.id.btn);
        t1=(EditText)findViewById(R.id.t1);
        t2=(EditText)findViewById(R.id.t2);
        pBar=(ProgressBar)findViewById(R.id.pBar);

        pBar.setVisibility(View.GONE);

        btn.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View view)
            {
                pBar.setVisibility(View.VISIBLE);
                new ExecuteTask().execute();
            }
        });
    }


    class ExecuteTask extends AsyncTask<String, Integer, String>
    {
        StringBuffer result;

        @Override
        protected String doInBackground(String... params) {

            try
            {
                String url = "http://localhost:8080/WebClient/index.jsp?t1="+t1.getText().toString();

                HttpClient client = new DefaultHttpClient();
                HttpGet request = new HttpGet(url);

                HttpResponse response = client.execute(request);

                BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));

                String line = "";
                result = new StringBuffer();

                while ((line = rd.readLine()) != null)
                {
                    result.append(line);
                }

                t2.setText(result.toString());
            }
            catch(Exception ex)
            {
                ex.printStackTrace();
            }

            return result.toString();
        }

        @Override
        protected void onPostExecute(String result) {
            pBar.setVisibility(View.GONE);
            t2.setText(result.toString());
        }
    }
}

输出

点击按钮后，我得到

错误日志

07-18 14:13:06.423 1394-1422/? W/audio_hw_generic: Not supplying enough data to HAL, expected position 9295997 , only wrote 9295920
07-18 14:13:06.442 8162-8185/com.example.akshay.httpclientdemo D/NetworkSecurityConfig: No Network Security Config specified, using platform default
07-18 14:13:06.452 8162-8185/com.example.akshay.httpclientdemo W/System.err: org.apache.http.conn.HttpHostConnectException: Connection to http://localhost:8080 refused
        at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:193)
        at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:169)
        at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:124)
        at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:366)
        at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:560)
        at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:492)
        at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:470)
07-18 14:13:06.453 8162-8185/com.example.akshay.httpclientdemo W/System.err:     at com.example.akshay.httpclientdemo.MainActivity$ExecuteTask.doInBackground(MainActivity.java:64)
        at com.example.akshay.httpclientdemo.MainActivity$ExecuteTask.doInBackground(MainActivity.java:50)
        at android.os.AsyncTask$2.call(AsyncTask.java:304)
        at java.util.concurrent.FutureTask.run(FutureTask.java:237)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
        at java.lang.Thread.run(Thread.java:761)
    Caused by: java.net.ConnectException: Connection refused
        at java.net.PlainSocketImpl.socketConnect(Native Method)
        at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:334)
        at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:196)
        at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:178)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:356)
        at java.net.Socket.connect(Socket.java:586)
        at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:124)
        at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:149)
        ... 14 more

    --------- beginning of crash
07-18 14:13:06.454 8162-8185/com.example.akshay.httpclientdemo E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
    Process: com.example.akshay.httpclientdemo, PID: 8162
    java.lang.RuntimeException: An error occurred while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:318)
        at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
        at java.util.concurrent.FutureTask.run(FutureTask.java:242)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
        at java.lang.Thread.run(Thread.java:761)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.StringBuffer.toString()' on a null object reference
        at com.example.akshay.httpclientdemo.MainActivity$ExecuteTask.doInBackground(MainActivity.java:83)
        at com.example.akshay.httpclientdemo.MainActivity$ExecuteTask.doInBackground(MainActivity.java:50)
        at android.os.AsyncTask$2.call(AsyncTask.java:304)
        at java.util.concurrent.FutureTask.run(FutureTask.java:237)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243) 
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133) 
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607) 
        at java.lang.Thread.run(Thread.java:761) 


    --------- beginning of system
07-18 14:13:06.455 1674-1829/system_process W/ActivityManager:   Force finishing activity com.example.akshay.httpclientdemo/.MainActivity
07-18 14:13:06.462 1674-1829/system_process W/ActivityManager:   Force finishing activity com.example.akshay.httpclientdemo/.MainActivity
    Duplicate finish request for ActivityRecord{fc02510 u0 com.example.akshay.httpclientdemo/.MainActivity t92 f}
07-18 14:13:06.496 1310-2049/? D/gralloc_ranchu: gralloc_alloc: Creating ashmem region of size 2691072
07-18 14:13:06.522 1310-1310/? E/EGL_emulation: tid 1310: eglCreateSyncKHR(1901): error 0x3004 (EGL_BAD_ATTRIBUTE)
07-18 14:13:06.667 1674-1691/system_process W/art: Long monitor contention with owner Binder:1674_2 (1686) at void com.android.server.am.ActivityManagerService.activityPaused(android.os.IBinder)(ActivityManagerService.java:6879) waiters=2 in void com.android.server.am.ActivityManagerService$3.handleMessage(android.os.Message) for 181ms
07-18 14:13:06.676 1674-2111/system_process W/art: Long monitor contention with owner Binder:1674_2 (1686) at void com.android.server.am.ActivityManagerService.activityPaused(android.os.IBinder)(ActivityManagerService.java:6879) waiters=3 in int com.android.server.am.ActivityManagerService.bindService(android.app.IApplicationThread, android.os.IBinder, android.content.Intent, java.lang.String, android.app.IServiceConnection, int, java.lang.String, int) for 188ms
07-18 14:13:06.811 6822-6839/com.example.akshay.todolist D/EGL_emulation: eglMakeCurrent: 0x997be600: ver 2 0 (tinfo 0xa6bf67e0)
07-18 14:13:06.846 8162-8178/com.example.akshay.httpclientdemo D/EGL_emulation: eglMakeCurrent: 0xb1a4e6a0: ver 2 0 (tinfo 0xa6b86880)
07-18 14:13:06.853 8162-8178/com.example.akshay.httpclientdemo D/OpenGLRenderer: endAllActiveAnimators on 0x99878300 (RippleDrawable) with handle 0x9953e240
07-18 14:13:06.872 1674-1752/system_process I/OpenGLRenderer: Initialized EGL, version 1.4
07-18 14:13:06.872 1674-1752/system_process D/OpenGLRenderer: Swap behavior 1
07-18 14:13:06.872 1674-1752/system_process W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
07-18 14:13:06.872 1674-1752/system_process D/OpenGLRenderer: Swap behavior 0
07-18 14:13:06.883 1674-1752/system_process D/EGL_emulation: eglCreateContext: 0x971032a0: maj 2 min 0 rcv 2
07-18 14:13:06.893 1674-1752/system_process D/EGL_emulation: eglMakeCurrent: 0x971032a0: ver 2 0 (tinfo 0x97d9b700)
07-18 14:13:06.902 1674-1752/system_process D/EGL_emulation: eglMakeCurrent: 0x971032a0: ver 2 0 (tinfo 0x97d9b700)
07-18 14:13:07.163 1394-1422/? W/audio_hw_generic: Not supplying enough data to HAL, expected position 9331460 , only wrote 9331200
    Not supplying enough data to HAL, expected position 9331210 , only wrote 9331200
07-18 14:13:07.181 1394-1422/? W/audio_hw_generic: Not supplying enough data to HAL, expected position 9332030 , only wrote 9331920
07-18 14:13:07.432 1674-4893/system_process I/WindowManager: Destroying surface Surface(name=com.example.akshay.httpclientdemo/com.example.akshay.httpclientdemo.MainActivity) called by com.android.server.wm.WindowStateAnimator.destroySurface:2016 com.android.server.wm.WindowStateAnimator.destroySurfaceLocked:882 com.android.server.wm.WindowState.removeLocked:1456 com.android.server.wm.WindowManagerService.removeWindowInnerLocked:2484 com.android.server.wm.WindowManagerService.removeWindowLocked:2442 com.android.server.wm.WindowManagerService.removeWindowLocked:2311 com.android.server.wm.WindowManagerService.removeWindow:2306 com.android.server.wm.Session.remove:202 
07-18 14:13:09.582 1394-1423/? W/audio_hw_generic: Not supplying enough data to HAL, expected position 9561758 , only wrote 9447120
07-18 14:13:23.586 1674-1758/system_process D/WifiNative-HAL: Failing getSupportedFeatureset because HAL isn't started
07-18 14:13:23.587 1674-1695/system_process E/BluetoothAdapter: Bluetooth binder is null
07-18 14:13:23.588 1674-1695/system_process E/BatteryStatsService: no controller energy info supplied
07-18 14:13:23.592 1674-1695/system_process E/KernelCpuSpeedReader: Failed to read cpu-freq: /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state (No such file or directory)
07-18 14:13:23.592 1674-1695/system_process E/KernelUidCpuTimeReader: Failed to read uid_cputime: /proc/uid_cputime/show_uid_stat (No such file or directory)
07-18 14:13:23.593 1674-1695/system_process E/BatteryStatsService: modem info is invalid: ModemActivityInfo{ mTimestamp=0 mSleepTimeMs=0 mIdleTimeMs=0 mTxTimeMs[]=[0, 0, 0, 0, 0] mRxTimeMs=0 mEnergyUsed=0}
07-18 14:14:00.138 1674-1674/system_process I/EntropyMixer: Writing entropy...
07-18 14:14:17.212 1674-1692/system_process I/ProcessStatsService: Prepared write state in 39ms

Answer 1

您正在尝试连接到本地主机。 Localhost是运行代码的计算机。但是您的服务器不在您的电话上（即使使用仿真器，该仿真器也是VM-它被视为单独的计算机）。因此，它没有连接，也没有获取任何数据。使用真实的url / ip地址。

您还需要考虑由于某种原因（例如，服务器已关闭）而无法连接的情况，并尝试比崩溃更优雅地处理它。您的问题在于，您依赖于doInBackground返回中结果为非null的结果。您可以通过将return result.toString移到try块中，然后将return null放在现在的位置来解决此问题。

如何从Android应用程序调用Java Web服务？

1 个答案: