Manual Setup of Java Web

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Manual Setup of Java Web

Last updated: 2024-01-06 17:43:10

Introduction
This article describes how to set up a Java Web environment on a Linux CVM.
This requires you to be familiar with common Linux commands, such as Installing Software via YUM in a CentOS Environment, and understand the versions of the installed software.
Software
These are the software involved:
CentOS is a distribution of the Linux operating system. We use CentOS 7.6 in this article.
Apache Tomcat provides a "pure Java" HTTP web server environment in which Java code can run. We use Apache Tomcat 8.5.47.
JDK, or Java Development Kit, is an implementation of the Java Platform. We use JDK 1.8.0_221 in this article.
Prerequisites
Setting up a Java Web environment requires a Linux CVM. If you have not purchased one yet, see Getting Started with Linux CVMs.
Directions
Step 1: Logging in to a Linux instance
Log in to a Linux instance using WebShell (recommended). You can also use other login methods that you are comfortable with:
Log in to a Linux instance using remote login software.
Log in to a Linux Instance using SSH
Step 2: Installing JDK
1. Download the JDK installation file. Go to the Java SE download page to select a version and download it.
Note:
Download the JDK file, save it locally, and upload it to your CVM. Otherwise, decompressing the file will result in errors.
If you are using Windows, use WinSCP to upload the file.
If you are using MacOS or Linux, use SCP to upload the file.
2. Run the following command to create a directory for JDK installation.
mkdir /usr/java
3. Run the following command to decompress JDK to the directory.
tar xzf jdk-8u221-linux-x64.tar.gz -C /usr/java
4. Run the following command to open profile.
vim /etc/profile
5. Press i to enter edit mode. Start a new line after export PATH USER ... and add the following:
export JAVA_HOME=/usr/java/jdk1.8.0_221 (replace 1.8.0_221 with your JDK version number)
export CLASSPATH=$JAVA_HOME/lib/tools.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib
export PATH=$JAVA_HOME/bin:$PATH
The result should be as follows:
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6. Press Esc and input :wq to save the file and go back.
7. Run the following command to read system environment variables.
source /etc/profile
8. Run the following command to check if JDK is installed properly.
java -version
If the following appears, the installation was successful.
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Step 3: Installing Tomcat
1. Run the following command to download Tomcat source codes. Select a version that suits you.
Note:
Refer to the Apache Tomcat official website for more information.
wget http://mirrors.tuna.tsinghua.edu.cn/apache/tomcat/tomcat-8/v8.5.47/bin/apache-tomcat-8.5.47.tar.gz
2. Run the following command to decompress the file.
tar xzf apache-tomcat-8.5.47.tar.gz
3. Run the following command to move the directory that contains Tomcat to /usr/local/tomcat/.
mv apache-tomcat-8.5.47 /usr/local/tomcat/
4. Run the following command to open server.xml.
vim /usr/local/tomcat/conf/server.xml
5. Find <Host … appBase="webapps”> and press i to enter edit mode. Replace appBase="webapps" with the following:
appBase="/usr/local/tomcat/webapps"
6. Press Esc and input :wq to save the file and go back.
7. Run the following command to create a file named setenv.sh.
vi /usr/local/tomcat/bin/setenv.sh
8. Press Enter to enter edit mode and input the following to set JVM memory variables.
JAVA_OPTS='-Djava.security.egd=file:/dev/./urandom -server -Xms256m -Xmx496m -Dfile.encoding=UTF-8' 
9. Press Esc and input :wq to save the file and go back.
10. Run the following command to start Tomcat.
/usr/local/tomcat/bin/startup.sh
If the following appears, Tomcat has been successfully started.
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Verifying the Environment Configuration
1. Run the following command to create a test file.
echo Hello World! > /usr/local/tomcat/webapps/ROOT/index.jsp
2. Open a browser window on your local machine and visit the following URL to check whether the environment configuration was successful.
http://[Public IP address of the CVM instance]:8080
If the following results appear, the environment configuration was successful.
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FAQ
If you encounter a problem when using CVM, refer to the following documents for troubleshooting based on your actual situation.
For issues about CVM login, see Password Login and SSH Key Login and Login and Remote Access.
For issues about the CVM network, see IP Addresses and Ports and Security Groups.
For issues about CVM disks, see System and Data Disks.