"How to run servlet"

The initiator asked, for example,: "How to configure environment variables" "How to run servlet"? This kind of problem is too much. Now I will write a beginner entry to read, so that I will have a guiding role in beginners!

The first is the download tool:

I suggest that beginners use EditPlus JDK, I think if I use, for example, JB, Eclipse, JCREATOR, although it is convenient to start, I don't know how to configure environment variables, so it is difficult to achieve it. Point.

Can be downloaded by the following address:

EditPlus (the latest version is V2.11): http://count.skycn.com/softdown.php? Id = 3641 & url = http: //sc-http.skycn.net/down/epp211a_cn.exe (you want photo registration code) Let's find it, there are many online) JDK (the latest version is java2sdk1_4_2): http://count.skycn.com/softdown.php? Id = 3116 & url = http: //sc-http.skycn.net/down/j2sdk -1_4_2-windows-i586.exe (this is for Windows)

Then install JDK, I put it below the C: JDK directory.

Then set the problem with ClassPath:

As the operating system uses PATH to search for executables, the Java runtime environment will also traverse classPath to find classes, even HelloWorld's simple programs, JVM also traversed each path defined by classpath until the corresponding file is found.

I believe that the system used is not 2K is XP, and then set the path as follows:

My Computer -> Properties -> Advanced -> Environmental Variables

Then add: C: JDKIN; C: JDKLIB at the back of the environment variable: C: JDKLIB;

It can also be configured: C: JDKIN;.; C: JDKLIBDT.jar; C: JDKLIB OOLS.jar

★ Remember: Environment variables. Remember can not be small, it represents the current path, if there is less error, etc. will say!

Dt.jar is about the class library of the operating environment, Tools.jar is the class library about some tools.

If there is no configuration: C: JDKIN, "Javac 'is not internal or external command, nor is it a running program or batch file." This error.

Below we will write an example program:

Open Editplus, create a new Java file, please enter the following, you want a word without leakage, and select the case:

Public class helloworld {public static void main (string [] args) {system.out.println ("Hello, World!");}}

Then save this file (Ctrl S) to HelloWorld.java, Java is sized, so case sensation must be divided, it is helloworld.java or other.

Run: Start -> Run -> cmd

Switch the directory to the current directory in the console:

Javac HelloWorld.javajava HelloWorld

You will see the output Hello, World!

Javac is a compiled command, which compiles helloWorld.java into HelloWorld.class

Java is an explanation command, and JVM explains the HelloWorld.class. At this time:

1. If Exception In Thread "Main" java.lang.noclassdeffounderror: HelloWorld is that you didn't add that in the environment variable. (Dot)

2, if Exception in Thread "main" java.lang.nosuchmethoderror: main or helloworld.java: 1: public class helloworld Must Be defined in a file called

"HelloWorld.java".

That is, you don't know how to write this HelloWorld, or if you have not saved as HelloWorld.java. This name must be the same as the name of the public class.

For the problem of environment variables, I will say this, let me say how to compile and run in Editplus, in Tools-> Parameter -> Configuring User Tools

1. Add a tool (add application)

Menu text: Compile Java Program

Program: C: JDKINJAVAC.exe

Parameters: File Name

Initial directory: file directory

2. Add Tools (Add Applications)

Menu text: Run Java Program

Program: C: JDKINJAVA.EXE

Parameters: File Name (excluding extensions)

Initial directory: file directory

The tool set name can be added, such as Debug Java Program.

Then in the Tools drop-down menu, you will see two options of Compile Java Program and Run Java Program, you can use Ctrl 1 compile and Ctrl 2 running programs.

Let's discuss the operating environment of the servlet:

To run the servlet, JSP / Servlet Container, I suggest that beginners use Tomcat.

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

Then extract this compression package to:

C: Tomcat

Then configure environment variables; add three system variables:

Java_Home: C: JDKTOMCAT_HOME: C: TomcatclassPath:% java_home% lib;% Tomcat_Home% lib

Tomcat's environment variable is configured, the following verifies whether Tomcat can run:

Go to the C: tomcatin in the console, run startup, then appear back to a window, and jump a big string, and finally the server has run.

Enter http: // localhost: 8080 /, the welcome interface, indicating that Tomcat is no problem. Then write your first servlet as above, write your first servlet.

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 ("