Sometimes your system may display a message with a servlet return value. There can be several reasons for this problem.
Which servlets return the response message you receive to the client. An HTTP request can use the GET or POST request methods, interrupted by a servlet’s doGet() or possibly doPost() method.
To create an effective web software package, oftenthere is a lot to know about the environment in which this task is performed. sheit should be noted that the server is possibly running its servletsor the characteristics of the client of the person processing requests. And noRegardless of the type of application you’re hosting, you needdefinitely ticket information thatthe application is being modified.
The series allows methods for servlets to access information. TOIn most cases, each of them returns a result of a specific concept. Compared to thishow to pass variables environment one CGI programs its input, servletThis approach has several advantages:
Enhanced type checking. ReceiveOther servlets help modern compilers detect bugs. This is a program that uses cgifunction for own getting environment variables.cannot be found until they cause runtime problems. We’ll seehow to make a cgi program and a servlet to find the port to be enabled Server works.
Script published by cgi, in Perl at:
$port calls $ENV'SERVER_PORT';
$port is an untyped variable. CGI programwritten C on Challenges:
port is a pointer to a string. due to an accidentIs there a chance of error. Name of environment variablesmay be misspelled (this happens often) fairly or usually the data type is the samenot what the environment returns vaguely.
On the other hand, a servlet derived from calls:
This De fixes a lot of occasional problems because the compiler canensure that there are no more spelling errors and that each reverse choice is what it isshould be.
Which method of the HttpServletRequest object is used if there is a chance of retrieving?
Understanding the HttpSession Interface HTTP session interface. Servlets can obtain additional information about the session from this HttpSession object, which should always be applied at the application level. The servlet allows you to get the HttpServletRequest getSession() method of the HttpServletRequest object to get or create an HttpSession object useful to the user.
Delayed settlement. When the server starts CGI training, the valuefor each aspect of the environment must be pre-calculated andpassed, the CGI program may not be using it. The server thatthe servlet provides an opportunity to improve performance during this timeCalculations and their implementation as needed. Interactions
How one can retrieve information in servlet?
Servlets now provide a number of methods to access this information. In most cases, each method control returns a specific result. By adapting this to how aspects of the environment are used to convey information to the CGI program, servlet selection has several advantages: Stronger style checking.
suffer more Servers. Onceopen the cgi program.Running it from a separate system. The only one with no means of communicationThis is the standard version of the program, the servlet can work withremote computer. As discussed in the previous step, it worksor a servlet, possibly a remote computer) (if or when it is attached to a processoutside the server (if necessary). Using this connectionmake servlet can only make special requests for computed informationthe server can provide. At the first level, a servlet can manage its own forum.arbitrary transformations with paths given pathsvirtual server and aliases.
Table 4-1. Environment variables and hence cgi corresponding servlet methods