maven environment configuration

Step 1: unzip the compressed package and put it into a folder in a non Chinese directory  

Compressed package download path: Maven – Download Apache Mavenhttp://maven.apache.org/download.cgi

Step 2: add system variables  

Step 1: right click on my computer and click properties

  Step 2: after entering, click Advanced system settings, and then click environment variables

  Step 3: click New in the system variable

  Step 4: copy the file path of the compressed package in step 1

The variable name is MAVEN_HOME  

The variable value is the copied file path  

  Step 5: find Path and click Edit

  Step 6: click new and fill in% MAVEN_HOME%\bin

  Verify whether the configuration is successful ----- enter cmd and open mvn -version as administrator

 

In this way, the configuration is successful  

Here maven is ready to use

However, because the maven warehouse is located abroad, the download efficiency is very slow, so we need to configure the local warehouse

Step 3: configure local warehouse

Step 1: enter the extracted apache-maven-3.5.0-bin

  Step 2: click conf

Step 3: open settings.xml with Notepad -- find a section labeled localRepository

Step 4: set the local repository - copy < localrepository > / path / to / local / repo < / localrepository > and change the address inside to the address you want to store

Step 5: find the label mirror

Step 6:   Here we want to use the image warehouse of alicloud private server

<mirror>
              <id>alimaven</id>
              <mirrorOf>central</mirrorOf>
              <name>aliyun maven</name>
              <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
    </mirror>

 Principle:

        After configuration
        1.adopt pom The coordinates of the file are read from the local warehouse first jar，If you have downloaded it, you can import it directly to the current project for use
        2.If there is no local warehouse, you will go to the alicloud image server to find what you need for development jar The package will be downloaded automatically when it is found         
          To the local warehouse and import the project
        3.If Alibaba cloud does not have an image warehouse, it will go abroad maven Central warehouse to download, if any, directly to the local warehouse            
          Library, and introduce the project to use
        4.If abroad maven If the central warehouse is not found, it is a code problem

Use of maven  

Step 1: eclipse sets the installation path of maven

Step 1: click Window to find Preferences

 

Step 2: find maven, click Installations, and click add on the right

  Step 3: fill in the path of your Apache Maven

  Step 4: check the new and apply it

  Step 5: enter User Settings, the second one on the right will find settings.xml, and the last path will change accordingly

  In this way, it is all configured, applied and closed

Step 2: use  

Step 1: double click Maven Project

  Step 2: select Internal in the Catalog, select the last one in the text field, and then Next

  Step 3: the second is the project name

  Step 4: the newly created project will have an error

Click the item and right-click Properyies

 

  Then find Project Facets

  Then change the Dynamic Web Module to 3.1 and Java to 1.8

  Then click the button in the figure above

 

Change the second column to webapp

Then open web.xml

 

  Change the content to

<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_3_1.xsd"
         version="3.1">
  <display-name>Archetype Created Web Application</display-name>
</web-app>

Then delete index.jsp and enter pom.xml

Change the content to

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.sg</groupId>
  <artifactId>T269_maven</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>T269_maven Maven Webapp</name>
  <url>http://maven.apache.org</url>
  <dependencies>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>4.0.0</version>
      <scope>provided</scope>
 </dependency> 
  </dependencies>
  <build>
    <finalName>T269_maven</finalName>
  </build>
</project>

You can then call the servlet

package com.sg.dome;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/dome")
public class DomeServlet extends HttpServlet{
	@Override
	protected void service(HttpServletRequest arg0, HttpServletResponse arg1) throws ServletException, IOException {
		System.out.println("hollw realization");
	}
}

Operation results: