Discussion :

[kaiser2003]

Bonjour

voila je vais peut être m'offrir un hebergement java/tomcat et je souhaite avoir une information avant de franchir le pas :

Si j'ai une application cliente java sur mon ordinateur, est il possible de me connecter à distance à une servlet afin de receuillir des informations qui se trouve dans une base de données chez mon hebergeur ?

Faut-il des droits speciaux ou autres ? et avec quel méthode proceder ?

merci




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[austin P.]

ce type de réponse se trouveront surement dans la FAQ de l'hébergeur

[kaiser2003]

bah euh non, l'hebergeur est tres tres avart en explication (3€ /mois...)

[lunatix]

bah euh non, l'hebergeur est tres tres avart en explication (3€ /mois...)

3€ par mois pour un hebergement tomcat ? c ou ???

[kaiser2003]

http://www.eatj.com il y a egalement un compte gratuit que j'essaie actuellement.

Mais bon apparement faut faire gaffe a ce qu'on fait :

Je fesait des essai sur le fichier server.xml et j'ai du me tromper => Bilan, mon site ne marche plus et je peut plus y acceder...

[austin P.]

on peux peut etre t'aider mais il faudrait que tu sois plus explicatif sur ton problème (une trace, un fichier de conf, etc...)

[kaiser2003]

ah et bien ca va être difficile, mais bon je peux toujours expliquer ce que je veux faire :

Imaginons par exemple que je developpe une application d'annuaire telephonique en java (application a executer sur un poste client). Toutes les donnees (nom, tel...) doivent etre enregistrer sur une base de donnees chez un hebergeur. Il faut donc que mon application se connecte a la base de donnees distante. Or, je ne desire pas utiliser JDBC dans cette application pour cause de securite (l'application contiendra le mot de passe du SGBD). J'ai fait pas mal de recherche avec des methode de crypto, mais le problème demeure helas puisque la cle est recupérable. Donc la seule solution que je voit, c'est de me connecter à une application serveur (style servlet) qui elle contiendra le mot de passe et effectura la requete puis enverra le resultat à l'application cliente.

Donc je veux juste savoir si c'est possible cette histoire sachant que mon hebergeur n'ouvre que le port 80.

voila, en esperant avoir ete un peut plus clair.

je peux te donner, le contenu du fichier server.xml :

Code :

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<Server port="8225" shutdown="SHUTDOWN" debug="0">
 
 
  <!-- Comment these entries out to disable JMX MBeans support -->
  <!-- You may also configure custom components (e.g. Valves/Realms) by 
       including your own mbean-descriptor file(s), and setting the 
       "descriptors" attribute to point to a ';' seperated list of paths
       (in the ClassLoader sense) of files to add to the default list.
       e.g. descriptors="/com/myfirm/mypackage/mbean-descriptor.xml"
  -->
  <Listener className="org.apache.catalina.mbeans.ServerLifecycleListener" debug="0" />
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" debug="0" />
 
  <!-- Global JNDI resources -->
  <GlobalNamingResources>
 
    <!-- Test entry for demonstration purposes -->
    <Environment name="simpleValue" type="java.lang.Integer" value="30" />
 
    <!-- Editable user database that can also be used by
         UserDatabaseRealm to authenticate users -->
    <Resource name="UserDatabase" auth="Container" type="org.apache.catalina.UserDatabase" description="User database that can be updated and saved">
    </Resource>
    <ResourceParams name="UserDatabase">
      <parameter>
        <name>factory</name>
        <value>org.apache.catalina.users.MemoryUserDatabaseFactory</value>
      </parameter>
      <parameter>
        <name>pathname</name>
        <value>conf/tomcat-users.xml</value>
      </parameter>
    </ResourceParams>
 
  </GlobalNamingResources>
 
  <!-- A "Service" is a collection of one or more "Connectors" that share
       a single "Container" (and therefore the web applications visible
       within that Container).  Normally, that Container is an "Engine",
       but this is not required.
 
       Note:  A "Service" is not itself a "Container", so you may not
       define subcomponents such as "Valves" or "Loggers" at this level.
   -->
 
  <!-- Define the Tomcat Stand-Alone Service -->
  <Service name="Catalina">
 
    <!-- A "Connector" represents an endpoint by which requests are received
         and responses are returned.  Each Connector passes requests on to the
         associated "Container" (normally an Engine) for processing.
 
         By default, a non-SSL HTTP/1.1 Connector is established on port 8080.
         You can also enable an SSL HTTP/1.1 Connector on port 8443 by
         following the instructions below and uncommenting the second Connector
         entry.  SSL support requires the following steps (see the SSL Config
         HOWTO in the Tomcat 5 documentation bundle for more detailed
         instructions):
         * If your JDK version 1.3 or prior, download and install JSSE 1.0.2 or
           later, and put the JAR files into "$JAVA_HOME/jre/lib/ext".
         * Execute:
             %JAVA_HOME%\bin\keytool -genkey -alias tomcat -keyalg RSA (Windows)
             $JAVA_HOME/bin/keytool -genkey -alias tomcat -keyalg RSA  (Unix)
           with a password value of "changeit" for both the certificate and
           the keystore itself.
 
         By default, DNS lookups are enabled when a web application calls
         request.getRemoteHost().  This can have an adverse impact on
         performance, so you can disable it by setting the
         "enableLookups" attribute to "false".  When DNS lookups are disabled,
         request.getRemoteHost() will return the String version of the
         IP address of the remote client.
    -->
 
    <!-- Define a non-SSL Coyote HTTP/1.1 Connector on port 8080 -->
    <Connector port="9225" maxThreads="150" minSpareThreads="25" maxSpareThreads="75" enableLookups="false" redirectPort="8443" acceptCount="100" debug="0" connectionTimeout="20000" disableUploadTimeout="true" />
    <!-- Note : To disable connection timeouts, set connectionTimeout value
     to 0 -->
 
	<!-- Note : To use gzip compression you could set the following properties :
 
			   compression="on" 
			   compressionMinSize="2048" 
			   noCompressionUserAgents="gozilla, traviata" 
			   compressableMimeType="text/html,text/xml"
	-->
 
    <!-- Define a SSL Coyote HTTP/1.1 Connector on port 8443 -->
    <!--
    <Connector port="8443" 
               maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
               enableLookups="false" disableUploadTimeout="true"
               acceptCount="100" debug="0" scheme="https" secure="true"
               clientAuth="false" sslProtocol="TLS" />
    -->
 
    <!-- Define a Coyote/JK2 AJP 1.3 Connector on port 8009 -->
    <Connector port="7225" enableLookups="false" redirectPort="8443" debug="0" protocol="AJP/1.3" />
 
    <!-- Define a Proxied HTTP/1.1 Connector on port 8082 -->
    <!-- See proxy documentation for more information about using this. -->
    <!--
    <Connector port="8082" 
               maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
               enableLookups="false"
               acceptCount="100" debug="0" connectionTimeout="20000"
               proxyPort="80" disableUploadTimeout="true" />
    -->
 
    <!-- An Engine represents the entry point (within Catalina) that processes
         every request.  The Engine implementation for Tomcat stand alone
         analyzes the HTTP headers included with the request, and passes them
         on to the appropriate Host (virtual host). -->
 
    <!-- You should set jvmRoute to support load-balancing via JK/JK2 ie :
    <Engine name="Standalone" defaultHost="localhost" debug="0" jvmRoute="jvm1">         
    --> 
 
    <!-- Define the top level container in our container hierarchy -->
    <Engine name="Catalina" defaultHost="localhost" debug="0">
 
      <!-- The request dumper valve dumps useful debugging information about
           the request headers and cookies that were received, and the response
           headers and cookies that were sent, for all requests received by
           this instance of Tomcat.  If you care only about requests to a
           particular virtual host, or a particular application, nest this
           element inside the corresponding <Host> or <Context> entry instead.
 
           For a similar mechanism that is portable to all Servlet 2.4
           containers, check out the "RequestDumperFilter" Filter in the
           example application (the source for this filter may be found in
           "$CATALINA_HOME/webapps/examples/WEB-INF/classes/filters").
 
           Request dumping is disabled by default.  Uncomment the following
           element to enable it. -->
      <!--
      <Valve className="org.apache.catalina.valves.RequestDumperValve"/>
      -->
 
      <!-- Global logger unless overridden at lower levels -->
      <Logger className="org.apache.catalina.logger.FileLogger" prefix="catalina_log." suffix=".txt" timestamp="true" />
 
      <!-- Because this Realm is here, an instance will be shared globally -->
 
      <!-- This Realm uses the UserDatabase configured in the global JNDI
           resources under the key "UserDatabase".  Any edits
           that are performed against this UserDatabase are immediately
           available for use by the Realm.  -->
      <Realm className="org.apache.catalina.realm.UserDatabaseRealm" debug="0" resourceName="UserDatabase" />
 
      <!-- Comment out the old realm but leave here for now in case we
           need to go back quickly -->
      <!--
      <Realm className="org.apache.catalina.realm.MemoryRealm" />
      -->
 
      <!-- Replace the above Realm with one of the following to get a Realm
           stored in a database and accessed via JDBC -->
 
      <!--
      <Realm  className="org.apache.catalina.realm.JDBCRealm" debug="99"
             driverName="org.gjt.mm.mysql.Driver"
          connectionURL="jdbc:mysql://localhost/authority"
         connectionName="test" connectionPassword="test"
              userTable="users" userNameCol="user_name" userCredCol="user_pass"
          userRoleTable="user_roles" roleNameCol="role_name" />
      -->
 
      <!--
      <Realm  className="org.apache.catalina.realm.JDBCRealm" debug="99"
             driverName="oracle.jdbc.driver.OracleDriver"
          connectionURL="jdbc:oracle:thin:@ntserver:1521:ORCL"
         connectionName="scott" connectionPassword="tiger"
              userTable="users" userNameCol="user_name" userCredCol="user_pass"
          userRoleTable="user_roles" roleNameCol="role_name" />
      -->
 
      <!--
      <Realm  className="org.apache.catalina.realm.JDBCRealm" debug="99"
             driverName="sun.jdbc.odbc.JdbcOdbcDriver"
          connectionURL="jdbc:odbc:CATALINA"
              userTable="users" userNameCol="user_name" userCredCol="user_pass"
          userRoleTable="user_roles" roleNameCol="role_name" />
      -->
 
      <!-- Define the default virtual host
           Note: XML Schema validation will not work with Xerces 2.2.
       -->
      <Host name="localhost" debug="0" appBase="webapps" unpackWARs="true" autoDeploy="true" xmlValidation="false" xmlNamespaceAware="false">
 
        <!-- Defines a cluster for this node,
             By defining this element, means that every manager will be changed.
             So when running a cluster, only make sure that you have webapps in there
             that need to be clustered and remove the other ones.
             A cluster has the following parameters:
 
             className = the fully qualified name of the cluster class
 
             name = a descriptive name for your cluster, can be anything
 
             debug = the debug level, higher means more output
 
             mcastAddr = the multicast address, has to be the same for all the nodes
 
             mcastPort = the multicast port, has to be the same for all the nodes
 
             mcastFrequency = the number of milliseconds in between sending a "I'm alive" heartbeat
 
             mcastDropTime = the number a milliseconds before a node is considered "dead" if no heartbeat is received
 
             tcpThreadCount = the number of threads to handle incoming replication requests, optimal would be the same amount of threads as nodes 
 
             tcpListenAddress = the listen address (bind address) for TCP cluster request on this host, 
                                in case of multiple ethernet cards.
                                auto means that address becomes
                                InetAddress.getLocalHost().getHostAddress()
 
             tcpListenPort = the tcp listen port
 
             tcpSelectorTimeout = the timeout (ms) for the Selector.select() method in case the OS
                                  has a wakup bug in java.nio. Set to 0 for no timeout
 
             printToScreen = true means that managers will also print to std.out
 
             expireSessionsOnShutdown = true means that 
 
             useDirtyFlag = true means that we only replicate a session after setAttribute,removeAttribute has been called.
                            false means to replicate the session after each request.
                            false means that replication would work for the following piece of code:
                            <%
                            HashMap map = (HashMap)session.getAttribute("map");
                            map.put("key","value");
                            %>
             replicationMode = can be either 'pooled', 'synchronous' or 'asynchronous'.
                               * Pooled means that the replication happens using several sockets in a synchronous way. Ie, the data gets replicated, then the request return. This is the same as the 'synchronous' setting except it uses a pool of sockets, hence it is multithreaded. This is the fastest and safest configuration. To use this, also increase the nr of tcp threads that you have dealing with replication.
                               * Synchronous means that the thread that executes the request, is also the
                               thread the replicates the data to the other nodes, and will not return until all
                               nodes have received the information.
                               * Asynchronous means that there is a specific 'sender' thread for each cluster node,
                               so the request thread will queue the replication request into a "smart" queue,
                               and then return to the client.
                               The "smart" queue is a queue where when a session is added to the queue, and the same session
                               already exists in the queue from a previous request, that session will be replaced
                               in the queue instead of replicating two requests. This almost never happens, unless there is a 
                               large network delay.
        -->             
        <!--
            When configuring for clustering, you also add in a valve to catch all the requests
            coming in, at the end of the request, the session may or may not be replicated.
            A session is replicated if and only if all the conditions are met:
            1. useDirtyFlag is true or setAttribute or removeAttribute has been called AND
            2. a session exists (has been created)
            3. the request is not trapped by the "filter" attribute
 
            The filter attribute is to filter out requests that could not modify the session,
            hence we don't replicate the session after the end of this request.
            The filter is negative, ie, anything you put in the filter, you mean to filter out,
            ie, no replication will be done on requests that match one of the filters.
            The filter attribute is delimited by ;, so you can't escape out ; even if you wanted to.
 
            filter=".*\.gif;.*\.js;" means that we will not replicate the session after requests with the URI
            ending with .gif and .js are intercepted.
        -->
 
        <!--
        <Cluster className="org.apache.catalina.cluster.tcp.SimpleTcpCluster"
                 managerClassName="org.apache.catalina.cluster.session.DeltaManager"
                 expireSessionsOnShutdown="false"
                 useDirtyFlag="true">
 
            <Membership 
                className="org.apache.catalina.cluster.mcast.McastService"
                mcastAddr="228.0.0.4"
                mcastPort="45564"
                mcastFrequency="500"
                mcastDropTime="3000"/>
 
            <Receiver 
                className="org.apache.catalina.cluster.tcp.ReplicationListener"
                tcpListenAddress="auto"
                tcpListenPort="4001"
                tcpSelectorTimeout="100"
                tcpThreadCount="6"/>
 
            <Sender
                className="org.apache.catalina.cluster.tcp.ReplicationTransmitter"
                replicationMode="pooled"/>
 
            <Valve className="org.apache.catalina.cluster.tcp.ReplicationValve"
                   filter=".*\.gif;.*\.js;.*\.jpg;.*\.htm;.*\.html;.*\.txt;"/>
        </Cluster>
        -->        
 
 
 
        <!-- Normally, users must authenticate themselves to each web app
             individually.  Uncomment the following entry if you would like
             a user to be authenticated the first time they encounter a
             resource protected by a security constraint, and then have that
             user identity maintained across *all* web applications contained
             in this virtual host. -->
        <!--
        <Valve className="org.apache.catalina.authenticator.SingleSignOn"
                   debug="0"/>
        -->
 
        <!-- Access log processes all requests for this virtual host.  By
             default, log files are created in the "logs" directory relative to
             $CATALINA_HOME.  If you wish, you can specify a different
             directory with the "directory" attribute.  Specify either a relative
             (to $CATALINA_HOME) or absolute path to the desired directory.
        -->
        <!--
        <Valve className="org.apache.catalina.valves.AccessLogValve"
                 directory="logs"  prefix="localhost_access_log." suffix=".txt"
                 pattern="common" resolveHosts="false"/>
        -->
 
        <!-- Logger shared by all Contexts related to this virtual host.  By
             default (when using FileLogger), log files are created in the "logs"
             directory relative to $CATALINA_HOME.  If you wish, you can specify
             a different directory with the "directory" attribute.  Specify either a
             relative (to $CATALINA_HOME) or absolute path to the desired
             directory.-->
        <Logger className="org.apache.catalina.logger.FileLogger" directory="logs" prefix="localhost_log." suffix=".txt" timestamp="true" />
 
      </Host>
 
    </Engine>
 
  </Service>
 
</Server>

[austin P.]

tu peut utiliser la solution de servlet qui renvoient des tableaux de chaines représentants le résultat de la requete ou du xml

[kaiser2003]

oui c'est se que comptait faire mais peux tu me dire des noms de methode pour acceder a la servlet et pour que le servlet me reponde histoire de savoir ou cherhcer.

merci

[dude]

C'est un truc comme ca que tu cherches ?

Code :

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    URL url = new URL("http://www.google.fr");
 
    URLConnection conn = url.openConnection();
 
    InputStream is = conn.getInputStream();
    byte[] bytes = new byte[1024];
    int len = 0;
 
    while ((len = is.read(bytes)) != -1) {
      System.out.println(new String(bytes, 0, len));
    }

[kaiser2003]

oui merci dude ca doit ressembler a ca mais si je veux recevoir des objets serialisés de la servlet quel code je peux bien faire ds la servlet et dans mon appli ?

(je sais je sis un peu insistant mais bon...)

[dude]

Ben essaye avec un ObjectOutputSteam dans ta servlet et un ObjectInputStream dans ton appli

[kaiser2003]

ah bah oui je suis un peu con moi... Merci beaucoup ca devrait allez

[souriss]

Salut,

Moi j'ai un problème identique. J'aimerai me connecter à une page WEB quelconque afin de récupérer les données de la page.

Voici mon code :
public static void main(String[] args) throws Exception {
//URL yahoo = new URL("http://syssta:8080/");
//URL yahoo = new URL("http://www.yahoo.fr");
URL yahoo = new URL("http://localhost:8080/");
URLConnection yc = yahoo.openConnection();
BufferedReader in = new BufferedReader(
new InputStreamReader(
yc.getInputStream()));
String inputLine;

while ((inputLine = in.readLine()) != null)
System.out.println(inputLine);
System.out.println(yahoo.getHost());
in.close();
}

Lorsque je me connecte au poste syssta, aucun problème mais pour le cas de yahoo et de mon poste cela ne fonctionne pas. Comment faire ?

Merci