Front end: Tomcat server deployment Web project

Article directory

1.1 C/S Architecture

Client/ServerClient/Server

As a stand-alone program, the client has a better graphics effect but is difficult to maintain.

1.2 B/S Architecture

Browser / Server Browser / Server

Enter the URL directly into the browser to visit

After the server is upgraded, the browser can directly access and obtain

However, the browser cannot carry too large resources, so the page effect and other experience are not as good as those of the client.

2.1 server

A web server is a container for running and publishing web applications. Only by placing the developed web project in this container can all users in the network access it through a browser.

2.2 Common servers

Tomcat (one of the mainstream web servers, suitable for beginners)
jetty
resin (very fast)

3.1 Tomcat installation

Official website: Apache Tomcat® - Apache Tomcat 10 Software Downloads

After the download is complete, decompress it directly. Note that the file path is best not to have a Chinese name.

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There are server management files under the bin folder

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The webapps project deployment file initially holds some example files

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3.2 Using Tomcat

Double click the bat file

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The command line port appears and remains open

If the interface closes directly after running the command line here, you need to check whether the JAVA_HOME configuration is correct

Checking method: Enter java on the command line to see if it is an executable command

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Garbled characters appear here because the encoding method of Tomcat needs to be modified

Enter the browser to visit Apache Tomcat/9.0.31

Observe the following interface, Tomcat starts successfully
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Double-click the bat file to terminate Tomcat operation

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At this time, accessing Apache Tomcat/9.0.31 will not be able to observe the content

3.3 Tomcat configuration

The port number is the unique identification of our access program, the default is 8080

Can be modified in server.xml under the conf folder

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Use Notepad to open and modify the port value after restarting Tomcat

You can successfully modify the default port number.

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Similarly, the configuration of other attributes can also be completed by modifying the text content.

3.4 Tomcat project deployment

Create a project file under the webapps folder

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The WEB-INF folder and the html file you will access are required under the project file

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Under the WEB-INF folder

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web.xml can be copied from root and others are empty folders

Visit: http://localhost:8080/firstweb/first.html
protocol: http
Domain name or hostname: locallhost
Port number: 8080
Project path: firstweb/first.html

So we can see the first.html page we wrote in toncat

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If the project path is selected incorrectly, a "resource does not exist" error will appear.

4.1 Servlet Technology

The server-side program (code, function implementation) can interactively process the request sent from the client to the server and complete the operation response.
A dynamic web technology
Basics of Java Web Program Development

4.2 Servlet configuration

Find the servlet-api.jar package under the lib file path

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save its path

Append to the environment variable Classpath of the system

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4.3 Configuration test

Create the MyServlet.java file

//简单Servlet示例
import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.ServletException;
import java.io.IOException;

public class MyServlet implements Servlet{
    
    
    public void init(ServletConfig config) throws ServletException{
    
    
    }
public void service(ServletRequest request,ServletResponse response) throws ServletException,IOException{
    
    
		System.out.println("My First Servlet");
}

public void destroy(){
    
    
}

public ServletConfig getServletConfig(){
    
    
		return null;
}	

public String getServletInfo(){
    
    
		return null;
}
}

First of all, make sure that the java javac version is consistent

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My versions are both 1.8.0_312

If you find that the two are inconsistent, it is because different versions of JDK are installed in the computer.

Delete different JDKs or adjust the path to put the bin path of a certain version of JDK in the front

Compile the above JAVA file on the command line

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Compiled files with .class suffix appear in the same folder

It indicates that the Servlet environment configuration is successful.

4.4 Servlet Deployment

Place the class file in the previously created classes folder

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Configure the web.xml file

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
                      http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
  version="4.0"
  metadata-complete="true">

<!-- 1.添加servlet节点 -->
<servlet>
    <servlet-name>MyServlet</servlet-name>
    <servlet-class>MyServlet</servlet-class>
</servlet>

<!-- 2.添加servlet-mapping节点 -->
<!-- 2.对Servlet做映射 name保持一致 -->
<!-- 2.url-pattern是访问Servlet的路径 -->
    
<servlet-mapping>
    <servlet-name>MyServlet</servlet-name>
    <url-pattern>/myservlet</url-pattern>
</servlet-mapping>
    
</web-app>