Posts

The Mystery of ProxyPassReverse

The mod_proxy_ajp module for Apache has many advantages over mod_jk for connecting a Tomcat server to an Apache front. For me, the crucial advantage was the ProxyPassReverseCookiePath directive, which allows me to map the session cookies of a Tomcat web application (other than the root application) into the root of a virtual host.

Unfortunately, many tutorials contain misleading advice, and recommend this pattern for the ProxyPassReverse, which will break if the web application issues a redirect:

ProxyPass /jspdir ajp://localhost:8009/jspdir
ProxyPassReverse /jspdir ajp://localhost:8009/jspdir

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Wrapping a Native Library with Maven

I recently converted a large project to build with Maven. The project contained both C++ and Java code, and produced a web application, a standalone server application, plus a number of small command line tools. The project used a large number of open-source Java libraries, and Maven tamed these easily. The native C++ library proved harder, and this is the approach I took.

The code snippets below are part of a complete example that builds a tiny Java/C++ application under Linux. This should port easily to other Unix-like platforms, and may provide some help to performing the same task under Windows. The example is available in tar.gz and zip formats.

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UTC, SQL Server, and Spring

I’ve recently been introducing the Spring Framework into an existing Java application, using it to speed up adding new features, while making the existing JDBC code more maintainable. One tricky area has been time handling: the application uses an older SQL Server version, so cannot take advantage of the implementation of timestamp with time zone in SQL Server 2008. All the time fields are kept in UTC, and the application must be careful that all the times are converted to and from UTC correctly. With pure JDBC this is handled explicitly, but with Spring JDBC access this is implicit.

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