- Login Gmail.
- On the Inbox page, scroll down to the bottom.
- At the bottom right corner, it prints "Last account activity" and "Details".
- Click on the "Details" link and an "Activity information" dialogue is shown.
- Click on the "Sign out all other Gmail web sessions" button.
Showing posts with label Web. Show all posts
Showing posts with label Web. Show all posts
Friday, May 10, 2019
Sign out all other Google Mail web sessions
If you have some Google login sessions in other computers that you forgot to logout, you can remotely logout the sessions.
Sunday, September 10, 2017
JSP: escape XML
In JSP:
<%@ taglib uri = "http://java.sun.com/jsp/jstl/functions" prefix="fn" %>
<% String str = "<abc & ' \">"; %>
<html>
<body>
<p>Escaped string: <%= fn:escapeXml(str) %> </p>
</body>
</html>
This requires the JSTL 1.2 JAR, which can be downloaded at https://mvnrepository.com/artifact/javax.servlet/jstl/1.2
<%@ taglib uri = "http://java.sun.com/jsp/jstl/functions" prefix="fn" %>
<% String str = "<abc & ' \">"; %>
<html>
<body>
<p>Escaped string: <%= fn:escapeXml(str) %> </p>
</body>
</html>
This requires the JSTL 1.2 JAR, which can be downloaded at https://mvnrepository.com/artifact/javax.servlet/jstl/1.2
Sunday, July 12, 2015
IE Compatibility
Different versions of IEs render web pages differently. That causes headache for web developers. Microsoft provides a compatibility solution for the old web sites. Since IE 8, the Internet Explorer browsers start to handle the X-UA-Compatible Meta Tag or HTTP response header. The web server can send it to tell the IE to render the web document in an older IE mode.
This link gives a detailed description of X-UA-Compatible: https://msdn.microsoft.com/en-us/library/ff955275%28v=vs.85%29.aspx
The values of X-UA-Compatible are:
This link explains the !DOCTYPE declaration and the IE modes: https://msdn.microsoft.com/en-us/library/ff955379%28v=vs.85%29.aspx
IE also provides a Compatibility View List that an end user can manually add a site to make it be rendered as EmulateIE7. Users can also control to display all local intranet sites or even all web sites in EmulateIE7 mode. (https://msdn.microsoft.com/en-us/library/ff955410%28v=vs.85%29.aspx)
Another very good article about this topic: https://sharovatov.wordpress.com/2009/05/18/ie8-rendering-modes-theory-and-practice/.
This link gives a detailed description of X-UA-Compatible: https://msdn.microsoft.com/en-us/library/ff955275%28v=vs.85%29.aspx
The values of X-UA-Compatible are:
- IE=5
- IE=7
- IE=8
- IE=9
- IE=10
- IE=11
- IE=edge
- IE=EmulateIE7
- IE=EmulateIE8
- IE=EmulateIE9
- IE=EmulateIE10
- IE=EmulateIE11
This link explains the !DOCTYPE declaration and the IE modes: https://msdn.microsoft.com/en-us/library/ff955379%28v=vs.85%29.aspx
IE also provides a Compatibility View List that an end user can manually add a site to make it be rendered as EmulateIE7. Users can also control to display all local intranet sites or even all web sites in EmulateIE7 mode. (https://msdn.microsoft.com/en-us/library/ff955410%28v=vs.85%29.aspx)
Another very good article about this topic: https://sharovatov.wordpress.com/2009/05/18/ie8-rendering-modes-theory-and-practice/.
Wednesday, July 16, 2014
PHP SoapClient error: Could not connect to host
It is a mystery why this piece of code caused a SoapFault exception:
<?php
$wsdl = "http://myws.toptip.ca/myws.wsdl";
$client = new SoapClient($wsdl, array(
"trace" => 1,
"exceptions" => 1));
$parameters = array("Element1" => "data1", "Element2" => "data2");
$response = $client->myFunction($parameters);
?>
An important fact was that the soap address location inside the WSDL is using a port other than 80, e.g.
http://myws.toptip.ca:8080/mywebservice
The exception was captured in /var/log/httpd/error_log:
PHP Fatal error: Uncaught SoapFault exception: [Http] Could not connect to host in ...
I tried to use Wireshark to capture the packets sent and received. Surprisingly, there was no packet sent out to the server from SoapClient. Not even the attempt to connect.
Accidentally, I found out an interesting thing. When I changed the port number of the soap address location in the WSDL file to the default (80), e.g.
http://myws.toptip.ca/mywebservice
SoapClient actually tried to connect to the service.
Why???
Sorry, I don't have the answer. If you have a clue, please let me know.
However, I have a workaround.
I installed the squid proxy on port 80 of the localhost. Then when creating the SoapClient object, I added the "proxy_host" and "proxy_port" options. Bang! It worked!! SoapClient sent the request to the proxy and it was successfully forwarded to the web service location.
<?php
$wsdl = "http://myws.toptip.ca/myws.wsdl";
$client = new SoapClient($wsdl, array(
"trace" => 1,
"exceptions" => 1));
$parameters = array("Element1" => "data1", "Element2" => "data2");
$response = $client->myFunction($parameters);
?>
An important fact was that the soap address location inside the WSDL is using a port other than 80, e.g.
http://myws.toptip.ca:8080/mywebservice
The exception was captured in /var/log/httpd/error_log:
PHP Fatal error: Uncaught SoapFault exception: [Http] Could not connect to host in ...
I tried to use Wireshark to capture the packets sent and received. Surprisingly, there was no packet sent out to the server from SoapClient. Not even the attempt to connect.
Accidentally, I found out an interesting thing. When I changed the port number of the soap address location in the WSDL file to the default (80), e.g.
http://myws.toptip.ca/mywebservice
SoapClient actually tried to connect to the service.
Why???
Sorry, I don't have the answer. If you have a clue, please let me know.
However, I have a workaround.
I installed the squid proxy on port 80 of the localhost. Then when creating the SoapClient object, I added the "proxy_host" and "proxy_port" options. Bang! It worked!! SoapClient sent the request to the proxy and it was successfully forwarded to the web service location.
Saturday, July 5, 2014
Create a Web Service from a WSDL with Eclipse
- Create an empty Dynamic Web Project (New->Project...->Web->Dynamic Web Project). Important Note: In the "Dynamic Web Project" dialogue, select a version less than 3.0 for the Dynamic web module version, e.g. 2.5. Otherwise, we will get an error of Apache Axis2 Web service runtime in Tomcat v7.0 Server does not support the service project <MyProject> in a later step.
- Right click on the project and select New->Others...
- In the "Select a wizard" dialogue, select Web Services->Web Service, and click the "Next" button.
- Select Top down Java bean Web Service for the Web Service type option. Input the URL of the web service in the Service definition box.
- Drag the slider on the left to choose Start service. Click the "Next" button.
- Follow the prompts to create the web service and start Tomcat.
- The web service skeleton is generated and we can fill in our implementation of the business logic.
Saturday, June 28, 2014
Web Dictionary Widget
If you like our Wiktionary and Google Translate, you will be interested in its sister project -- our new Web Dictionary Widget. Check it out at dic.solezero.com.
Saturday, January 11, 2014
Miscellaneous problems with GWT/Spring/Hibernate/Eclipse in web development
Debug breakpoints are not triggered in GWT client package.
Reason: Debug mode form GWT client package only works in the Development mode. In the production mode, the GWT client side runs the compiled Javascript that has lost the information of the debug breakpoints.Solution: Use the URL of http://127.0.0.1:8888/myproject.html?gwt.codesvr=127.0.0.1:9997 -- note: the "?gwt.codesvr=127.0.0.1:9997" part refers to the code server running the Java version of the client package.
When using GWT SimplePager setPageSize() for the paging of a CellTable, only the first page has data. Pressing the Next button shows no more data and pressing the Back button may raise a null-pointer exception.
Solution: Use a ListDataProvider<T> to inject the data of the list to the widget, e.g.CellTable<DataObj> cellTable = new CellTable<DataObj>();
...
cellTable.addColumn(...);
...
cellTable.setRowData(0, dataList);
cellTable.setRowCount(dataList.size(), true);
...
// Add a pager
SimplePager.Resources pagerResources = GWT.create(SimplePager.Resources.class);
SimplePager simplePager = new SimplePager(TextLocation.CENTER, pagerResources, false, 0, true);
...
simplePager.setDisplay(cellTable);
simplePager.setPageSize(10);
...
// Must use ListDataProvider for correct paging.
ListDataProvider<DataObj> dataProvider = new ListDataProvider<DataObj>();
dataProvider.addDataDisplay(cellTable);
dataProvider.setList(dataList);
org.hibernate.MappingException: Repeated column in mapping for entity: ... column: ... (shold be mapped with insert="false" update="false")
Reason: The column is used as JoinColumn too. If different values are set for the "Column" and "JoinColumn", it will cause inconsistence. Hibernate only allows the changes on one place when doing the insertion or update.Solution: Use "insertable=false, updatable=false" in all but one mapping, e.g.
@Column (name="...", insertable=false, updatable="false")
or
@JoinColumn (name="...", referancedColumnName="...", insertable=false, updatable=false)
Hibernate criteria.list() returns empty list.
Solution: Add<property name="packageToScan" value="package.to.scan.for.the.entity.classes" />
to
<bean id=sessionFactory"
class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
GWT WindowBuilder cannot find the CSS file. Trying to add new style generates this error message "There are no CSS files referenced from modules HTML."
Reason: The WindowBuilder cannot access the CSS under the "war" directory.Solution: Create a new subdirectory where the ???.gwt.xml locates. By default, GWT recognizes the directory name as "public". If we want to use another name, such as "css", we need to add
<public path="css">
into the ???.gwt.xml file. We also add the file name of the CSS file to the ???.gwt.xml file
<stylesheet src="???.css" />
The GWT compiler will copy all the files under "public" to "war/my-project-name" directory.
Exception from Hibernate 4 when calling sessionFactory.getCurrentSession(): Caused by: org.hibernate.HibernateException: No Session found for current thread.
Solution: Verify that the configuration for transactionManager is correct. Add @Transactional to the method that calls sessionFactory.getCurrentSession().Exception from Hibernate: Caused by: org.hibernate.ObjectNoFoundException: No row with the given identifier exists: [...]
Reason: The Entity has a one-to-one, one-to-many etc mapping and the referred Entity has no data for this reference. For example, the User table can be joined to the ContactInfo table. For a user that does not have a record in the ContactInfo table, such an exception will be thrown.Solution: Use the @NotFound(action=NotFoundAction.IGNORE) annotation for the reference member. The member will then be set as null in the returned Entity.
Associated entities are not saved when saving an entity.
Reason: By default, we have to explicitly save each one.Solution: Use CascadeType for the mapping, e.g. @OneToOne(cascade=CascadeType.PERSIST), @OneToMany(cascade=CascadeType.ALL), etc. Hibernate will then automatically propagate your action to the associated entity.
Exception: Caused by: org.hibernate.AnnotationException: No identifier specified for entity
Reason: Annotation @Id is missing. Each @Entity needs an @Id. It is the primary key in the database.To automatically generate column names in uppercase from property name.
Solution: Create a naming strategy from hibernate DefaultNamingStrategy:public class MyNamingStrategy extends DefaultNamingStrategy {
@Override
public String propertyToColumnName(String propertyName) {
return proertyName.toUpperCase();
}
}
In the configuration XML file, add:
<property name="namingStrategy">
<bean class="package.path.to.MyNamingStrategy" />
</property>
OneToMany unidirectional mapping throws exception: org.hibernate.MappingException: Unable to find column with logical name: ??? in org.hibernate.mapping.Table(???) and its related supertables and secondary tables.
Reason: The elments of "name" and "referencedColumnName" in JoinColumn annotation depend on the context (see http://docs.oracle.com/javaee/6/api/javax/persistence/JoinColumn.html).Solution: In my case, I need to switch the values of them. And refeencedColumnName should refer to a PHYSICAL column in the source table.
When primary key is used as @OneToOne mapping and @JoinColumn, an exception is thrown: Caused by: java.lang.NullPointerException at org.hibernate.type.descriptor.java.AbstractTypeDescriptor.extractHashCode (AbstractTypeDescriptor.java:88)
Solution: Restructure the code to make sure the target object is persisted first so that the primary key is known when persisting the object in question.Exception: Caused by: org.hibernate.PersistentObjectException: detached entity passed to persist.
Reason 1: Inconsistency issue. E.g. Class A has a @OnetoMany reference to class B, while class B has a @ManyToOne reference to class A. We need to satisfy both side of the relationship before performing persistence, i.e. objA.getB().add(objB); objB.setA(objA).Reason 2: Manually set the value for the field of GenerationType.AUTO.
Exception: org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role ...... could not initialize proxy - no Session
Solution: use Hibername.initialize() to initialize the proxy before the session is closed.Exception: com.google.gwt.user.client.rpc.SerializationException: Type 'org.hibernate.collection.internal.PersistentBag' was not included in the set of types which can be serialized by this SerializationPolicy or its Class object could not be loaded. For security purposes, this type will not be serialized.
Solution: http://www.gwtproject.org/articles/using_gwt_with_hibernate.html: 1. write our own light weight DTO, separating from Entity bean. 2. use Dozer to generate DTO for each Entity bean. 3. use Gilead (hibernate4gwt) lib.
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