I. History of development
- The site now has a Web container in addition to the file system.
- The former is used in response to a static page request, which responds to a dynamic page request.
- A static page request returns a fixed static page that cannot manipulate the database, while a dynamic page request can manipulate the database and get the requested results page in the form of patchwork code.
Second, the construction of Dynamic Web site technology
- A dynamic Web site, a Web site that can respond to dynamic requests and that can interact with users.
- There are several technical systems for building dynamic Web sites, and different technical systems are suitable for building dynamic Web sites of different sizes:
- CGI (deprecated), because this technology is for each request, create a new process on the server side, compared to time-consuming resources, so now the technology is basically obsolete.
- PHP, for building personal or small web sites
- ASP, available only with IIS Server +sql Server database, for building personal or small web sites
- ASP. NET, only for building midsize Web sites
- JSPfor the development of medium-sized and large web sites. JSP developed a Web site compatible with a variety of servers such as tomcat/jboss/weblogic and so on, and has a good cross-platform migration characteristics. JSP is based on the Java language servlet "server-side applet" developed, because the servlet development process is more complex, so sun company according to the characteristics of ASP technology, Java servlet Packaging, thus forming a new technology--jsp.
Third, from Java SE to Java EE
- Java EE is developed on the basis of Java SE
- Java EE is a standard development architecture designed to develop enterprise-class applications
- b/S As the main development mode in the development of Java EE
- Java EE has a number of components, containers, and services that make it easier to develop enterprise-class applications, compared to Java SE
- Java EE container: Java EE has 4 more containers relative to Java SE, the Web container/ejb container/app container/application Client Container. So what are these Java EE containers for? A: Each Java EE container is responsible for the operation of one component, and the presence of these containers ensures that the operations between the various components do not interfere with each other. To build an enterprise-level program (that is, a Web site), Webcontainer containers are essential and other containers are optional.
- Java EE components: as opposed to Java SE applications, enterprise applications divide all components into classes, which are also known as different types of Java EE components, and different types of Java EE components will run in different Java EE containers. And do not affect each other. As with the JSP and servlet components running in the Java EE webcontainer container, the EJB container container is running the components related to transaction management.
- Java EE Services: to facilitate the development of enterprise-class applications (Web applications), accelerate the development process. Java EE, in contrast to Javase, has a number of APIs that are divided into groups called different Java EE services, respectively. Mainly include:
- HTTP protocol-related APIs (this protocol is required for general Web applications)
- PMI-IIOP protocol-related APIs (used primarily when accessing EJB components)
- Java IDL-related APIs (primarily for accessing external CORBA services)
- JTA related APIs (primarily for transactional processing)
- JDBC-related APIs (primarily for database operations)
- JMS-related APIs (primarily for sending point-to-point messages)
- JavaMail related APIs (primarily for sending mail)
- JAF related APIs (primarily used to encapsulate data in messages)
- Jndi-related APIs (primarily used to bind names and objects into Key-value pairs)
- JAXP and Stax related APIs (primarily for parsing XML files)
- Jaas-related APIs (for user authentication actions)
- JSF-related APIs (this is a set of MVC implementation components officially provided by Java EE)
- Jstl related API (JSP page tag support library, it is because Java EE provides this support library, Web application JSP page can use the corresponding tag)
- JCA-related APIs (for connecting applications with different schemas)
- SAAJ/JAXR related APIs (primarily for heterogeneous Distributed program development)
As can be seen, Java applet does not support any Java EE API (ie Java EE service), so Java applet is now basically abolished, now few people develop Java applet program.
Java Web Combat Development--------"brush the second-----" experience