我正在玩这个多插槽服务器Java代码，代码以某种方式工作，我想在这里添加一个数据库所以我修改它遇到了这个奇怪的错误：
TryServerActivity.java
public class TryServerActivity extends Activity {
DataSource mDataSource;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// instantiate DataSource as commented by reTs
mDataSource = new DataSource(this);
mDataSource.open();
MultipleSocketServer.main();
}
@Override
protected void onResume(){
mDataSource.open();
super.onResume();
Log.d("Server", "onResume()");
}
@Override
protected void onStop(){
mDataSource.close();
super.onStop();
Log.d("Server", "onStop()");
}
@Override
protected void onDestroy(){
mDataSource.close();
super.onDestroy();
Log.d("Server","onDestroy");
}
@Override
protected void onPause() {
mDataSource.close();
super.onPause();
Log.d("Server", "onPause()");
}
}
DataSource.java
public class DataSource implements DBConstants{
private SQLiteDatabase mSQLiteDatabase;
private DatabaseHelper mDatabaseHelper;
public DataSource (Context context){
mDatabaseHelper = new DatabaseHelper(context);
}
public void open() throws SQLiteException {
mSQLiteDatabase = mDatabaseHelper.getWritableDatabase();
}
public void close() {
mDatabaseHelper.close();
}
public void addUser(String name, String role, String ipaddress, String vendor, String resolution, String media, String timestamp){
ContentValues values = new ContentValues();
values.put(NAME, name);
values.put(ROLE, role);
values.put(IP_ADDRESS, ipaddress);
values.put(VENDOR_ID, vendor);
values.put(RESOLUTION, resolution);
values.put(MEDIA_SUBSYSTEM, media);
values.put(TIMESTAMP, timestamp);
mSQLiteDatabase.insert(DB_TABLENAME_USERS, null, values);
}
}
}
MultipleSocketServer.java
public class MultipleSocketServer implements Runnable {
private Socket connection;
private String TimeStamp;
private int ID;
DataSource mDataSource;
public static void main() {
int port = 19999;
int count = 0;
try{
ServerSocket socket1 = new ServerSocket(port);
System.out.println("MultipleSocketServer Initialized");
while (true) {
Socket connection = socket1.accept();
Runnable runnable = new MultipleSocketServer(connection, ++count);
Thread thread = new Thread(runnable);
thread.start();
}
} catch (Exception e) {
e.printStackTrace();
}
}
MultipleSocketServer(Socket s, int i) {
this.connection = s;
this.ID = i;
}
public void run() {
try {
BufferedInputStream is = new BufferedInputStream(connection.getInputStream());
InputStreamReader isr = new InputStreamReader(is);
int character;
StringBuffer process = new StringBuffer();
while((character = isr.read()) != 13) {
process.append((char)character);
}
System.out.println(process + " ID: " + ID);
String details = process.toString();
System.out.println("details: " + details);
String name = "", role = "", ipaddress = "", vendor = "", resolution = "", media = "media", timestamp = "";
String [] split = details.split(",");
for(int i = 0; i < split.length; i++){
Log.d("MULTIPLESOCKET", "split[" + i + "]: " + split[i].toString());
switch (i){
case 0: name = split[i].toString(); break;
case 1: role = split[i].toString(); break;
case 2: ipaddress = split[i].toString(); break;
case 3: vendor = split[i].toString(); break;
case 4: resolution = split[i].toString(); break;
case 5: timestamp = split[i].toString(); break;
}
}
Log.d("MULTIPLE", "name: " + name + " role: " + role + " ipadd: " + ipaddress);
Log.d("MULTIPLE", "vendor: " + vendor + " resolution: " + resolution + " media: " + media + " time: " + timestamp);
mDataSource.addUser(name, role, ipaddress, vendor, resolution, media, timestamp);
try {
Thread.sleep(10000);
} catch (Exception e){
System.out.println("thread");
}
TimeStamp = new java.util.Date().toString();
String returnCode = "Server repsonded at "+ TimeStamp + (char) 13 + "hi";
BufferedOutputStream os = new BufferedOutputStream(connection.getOutputStream());
Log.d("SServer", "connect input: " + connection.getInputStream());
Log.d("SServer", "connect close: " + connection.isClosed());
OutputStreamWriter osw = new OutputStreamWriter(os, "US-ASCII");
osw.write(returnCode);
osw.flush();
} catch (Exception e) {
System.out.println(e);
System.out.println("run");
} finally {
try {
connection.close();
}catch (IOException e){
e.printStackTrace();
}
}
}
}
logcat的：
E/AndroidRuntime(12050): FATAL EXCEPTION: main
E/AndroidRuntime(12050): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tryserver/com.tryserver.TryServerActivity}: java.lang.NullPointerException
E/AndroidRuntime(12050): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
E/AndroidRuntime(12050): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
E/AndroidRuntime(12050): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
E/AndroidRuntime(12050): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
E/AndroidRuntime(12050): at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime(12050): at android.os.Looper.loop(Looper.java:123)
E/AndroidRuntime(12050): at android.app.ActivityThread.main(ActivityThread.java:3683)
E/AndroidRuntime(12050): at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime(12050): at java.lang.reflect.Method.invoke(Method.java:507)
E/AndroidRuntime(12050): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
E/AndroidRuntime(12050): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
E/AndroidRuntime(12050): at dalvik.system.NativeStart.main(Native Method)
E/AndroidRuntime(12050): Caused by: java.lang.NullPointerException
E/AndroidRuntime(12050): at com.tryserver.TryServerActivity.onCreate(TryServerActivity.java:27)
E/AndroidRuntime(12050): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
E/AndroidRuntime(12050): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
E/AndroidRuntime(12050): ... 11 more
W/ActivityManager( 104): Force finishing activity com.tryserver/.TryServerActivity
W/ActivityManager( 104): Force finishing activity com.android.settings/.ManageApplications
另一个logcat：
I/System.out(13763): MultipleSocketServer Initialized
W/ActivityManager( 104): Launch timeout has expired, giving up wake lock!
W/ActivityManager( 104): Activity idle timeout for HistoryRecord{40661060 com.tryserver/.TryServerActivity}
D/dalvikvm( 1427): GC_EXPLICIT freed 8K, 54% free 2547K/5511K, external 716K/1038K, paused 17ms
I/System.out(13763): ttttty,Teacher,192.168.1.138,Andy-tech,800x480, at Thu Jun 21 11:16:41 GMT+08:00 2012 ID: 1
I/System.out(13763): details: ttttty,Teacher,192.168.1.138,Andy-tech,800x480, at Thu Jun 21 11:16:41 GMT+08:00 2012
D/MULTIPLESOCKET(13763): split[0]: test
D/MULTIPLESOCKET(13763): split[1]: Teacher
D/MULTIPLESOCKET(13763): split[2]: 192.168.1.138
D/MULTIPLESOCKET(13763): split[3]: Andy-tech
D/MULTIPLESOCKET(13763): split[4]: 800x480
D/MULTIPLESOCKET(13763): split[5]: at Thu Jun 21 11:16:41 GMT+08:00 2012
D/MULTIPLE(13763): name: ttttty role: Teacher ipadd: 192.168.1.138
D/MULTIPLE(13763): vendor: Andy-tech resolution: 800x480 media: VNC time: at Thu Jun 21 11:16:41 GMT+08:00 2012
I/System.out(13763): java.lang.NullPointerException
I/System.out(13763): run