How to run jsp file

How to run the jsp file: First, the client sends a Request request, and the JSP Container translates the JSP into the Servlet source code; then compiles the generated Servlet source code and loads it into the memory for execution; finally, the result is Just respond to the client.

When the client browser sends a request to the server to access a JSP page, the server loads the corresponding JSP page according to the request and compiles the page. , and then execute.

Recommended course: Java Tutorial.

The execution process of the page is shown in the figure below:

#The client sends a request to the server through the browser, and the request contains the requested resource path, so that when the server receives the request, it can know the requested content.

The server loads the corresponding JSP file according to the received client request.

The JSP engine in the Web server will convert the loaded JSP file into a Servlet.

The JSP engine compiles the generated Servlet code into a Class file.

The server executes this Class file.

Finally, the server sends the execution results to the browser for display.

As you can see from the above explanation, after the JSP file is converted by the JSP engine, it is compiled into a Class file. Finally, the server responds to the client's request by executing this Class file. The third and fourth steps constitute the translation stage in the JSP processing process, while the fifth step is the request processing stage.

But not every request needs to be repeated. When the server receives a request for a page for the first time, the JSP engine begins to compile the requested JSP file into a Class file according to the above process. When the page is requested again, if there are no changes to the page, the server will directly call the corresponding Class file for execution. Therefore, when a JSP page is requested for the first time, there will be some delay, but when accessed again, it will feel much faster. If the requested page has been modified, the server will recompile the file and then execute it.

How jsp runs

**jsp - JSP engine converted into Servlet - Java compiled into .class file - by Java virtual machine Explanation and execution

The execution process of Web container processing JSP file requests mainly includes the following four parts:

The client issues a Request request

JSP Container translates JSP into Servlet Source code

Compile the generated Servlet source code and load it into the memory for execution

Response the result to the client

Many people will think that JSP The execution performance will be very different from that of Servlet. In fact, the difference in execution performance is only in the first execution. Because JSP will be compiled into a Servlet class file, that is, .class, after it is executed for the first time. When the execution is called repeatedly, the Servlet generated for the first time will be executed directly without recompiling JSP into Servelt. Therefore, in addition to the first compilation taking a long time, the execution speed of JSP and Servlet is almost the same.

When executing a JSP web page, it can usually be divided into two periods: Translation Time and Request Time

Translation period: JSP web pages are transferred into Servlet classes.

Request period: After the Servlet class is executed, the response result is sent to the client.

Two things were done during the translation period:

Translation period: Transfer the JSP web page to Servlet source code.java.

Compilation period: Compile the Servlet source code.java Into Servlet class.class.

When the JSP webpage is executing, the JSP Container will do the checking work. If it is found that the JSP webpage has been updated and modified, the JSP Container will compile the JSP into a Servlet again; if the JSP has not been updated. , directly execute the previously generated Servlet.**

The above is the detailed content of How to run jsp file. For more information, please follow other related articles on the PHP Chinese website!