Brief Introduction to Servlet runtime environment Configuration

What does the Servlet runtime environment need?

First, we will discuss JSP/Servlet iner for running Servlet. I suggest you use Tomcat for beginners.

Tomcat Latest Version 5.0): http://cvs.apache.org/builds/jakarta-tomcat-5/nightly/jakarta-tomcat-5-bin-20030725.zip

Decompress the package:

C: \ Tomcat

Then configure the environment variables of the Servlet runtime environment. Add three system variables:

 
 

  
  
JAVA_HOME: C:\JDK  
  
  
TOMCAT_HOME: C:\Tomcat  
  
  
CLASSPATH: %JAVA_HOME%\lib;%TOMCAT_HOME%\lib 
 
 

The environment variables of Tomcat are configured. Check whether Tomcat can run as follows:

In the console, go to the C: \ Tomcat \ bin directory and run startup. Then, a window is displayed, which means that the Server is running.

Enter http: // localhost: 8080 in the browser. If the welcome page appears, it means Tomcat is okay. Write your first Servlet as above.

 
 

  
  
import java.io.*;  
  
  
import javax.servlet.*;  
  
  
import javax.servlet.http.*;  
  
  
public class HelloWorld extends HttpServlet  
  
  
{  
  
  
public void doGet(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException  
  
  
{  
  
  
 
  
  
response.setContentType("text/html");  
  
  
PrintWriter out = response.getWriter();  
  
  
out.println("﹤h﹤tml﹥﹤head﹥﹤title﹥");  
  
  
out.println("This is my first Servlet");  
  
  
out.println("﹤/title﹥﹤/head﹥﹤body﹥");  
  
  
out.println("﹤h1﹥Hello,World!﹤/h1﹥");  
  
  
out.println("﹤/body﹥﹤/html﹥");  
  
  
 
  
  
}  
  
  
} 
 
 

Then use javac HelloWorld. java to compile the file. If the file cannot be imported javax. servlet .*

Then, copy the servlet. jar file in C: \ Tomcat \ common \ lib to C: \ JDK \ jre \ lib \ ext and compile it again!

Then, in the Tomcat directory C: \ Tomcat \ webapps \ ROOT, follow the following file structure:

ROOT \ index.html

ROOT \ welcom. jsp

ROOT \ WEB-INF \ lib \ MyServlet. jar if your servlet. class is typed into a. jar file, put it under lib)

ROOT \ WEB-INF \ classes \ HelloWorld. class (put the above generated HelloWorld. class file in this)

Then, enter http: // localhost: 8080/servlet/HelloWorld in the browser. The Error 404 -- Not Found is returned by the Server.

What's going on?

Servlet must use C: \ Tomcat \ webapps \ ROOT \ WEB-INF directory under the web. xml file registration, open this web. xml file with EP, add in it:

 
 

  
  
﹤servlet﹥  
  
  
﹤servlet-name﹥HelloWorld﹤/servlet-name﹥  
  
  
﹤servlet-class﹥HelloWorld﹤/servlet-class﹥  
  
  
﹤/servlet﹥  
  
  
﹤servlet-mapping﹥  
  
  
﹤servlet-name﹥HelloWorld﹤/servlet-name﹥  
  
  
﹤url-pattern﹥/servlet/helloworld﹤/url-pattern﹥  
  
  
﹤/servlet-mapping﹥  
 
 

Such a structure

 
 

  
  
﹤servlet﹥  
  
  
﹤servlet-name﹥HelloWorld﹤/servlet-name﹥  
  
  
﹤servlet-class﹥HelloWorld﹤/servlet-class﹥  
  
  
﹤/servlet﹥ 
 
 

Indicates the included servlet class. The following structure:

 
 

  
  
﹤servlet-mapping﹥  
  
  
﹤servlet-name﹥HelloWorld﹤/servlet-name﹥  
  
  
﹤url-pattern﹥/servlet/HelloWorld﹤/url-pattern﹥  
  
  
﹤/servlet-mapping﹥ 
 
 

Specifies the URL mode to which HelloServlet maps.

After modifying web. xml, restart the Server and then enter http: // localhost: 8080/servlet/HelloWorld. Then, a large Hello, World! Waiting for you.

After configuring the Servlet runtime environment, we can start our interesting Servlet programming journey.

1. Multi-thread synchronization in Servlet and JSP
2. Enhanced Servlet and JSP security without modifying code
3. Configuration of JSP, Servlet, and Bean in Tomcat
4. How to Improve Servlet and JSP Application Efficiency
5. Functions and principles of several encodings in JSP and Servlet