Gae Development History

1. Build a Gae Development Environment
Go to the official Gae website.

2. Develop a sample application
The official website provides an example of creating helloworld, which shows the steps for creating your first Gae application. This example is based on Servlet and JSP technologies. However, we want to use the Struts framework to develop our own applications. For more information, see.

3. How to view Data
For applications uploaded to Gae, log on to the ingress using your Google account.

4. jsp does not support El
There are two reasons for this problem. The project generated by the Gae Eclipse plug-in uses the servlet2.5 standard by default, while the 2.5 version ignores El by default, so the use of El in JSP will fail. Add iselignored = "false" to the header of the page that requires El, for example:
<% @ Page Language = "Java" contenttype = "text/html; charset = UTF-8" pageencoding = "UTF-8" %>
Changed:
<% @ Page Language = "Java" contenttype = "text/html; charset = UTF-8" pageencoding = "UTF-8" iselignored = "false" %>

5. Gae does not support drawing functions in the Java. AWT package.
When you need a Random verification code for logon, you generally need to use these drawing functions to generate a random image, but the usual practice is not allowed in Gae. Someone put forward an idea of realizing the verification code on the internet, see http://isend-blog.appspot.com/2010/03/25/captcha_on_GAE.html

6. Gae data is stored in JPA mode. The difference between insert and update is true.
When persist is an entity, if the key of this entity already exists, it will update instead of insert

5. Google App Engine supports spring-ORM (2.5.6 ).
Gae does not support spring-ORM because it references the classes in the javax. Naming package, and these classes are not supported by Gae. In the spring-orm-2.5.6.jar to move the class can:

Persistenceannotationbeanpostprocessor. Class
Persistenceannotationbeanpostprocessor $ persistenceelement. Class
Persistenceannotationbeanpostprocessor $2. Class
Persistenceannotationbeanpostprocessor $1. Class