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Deploying Java Web on CentOS

Last updated: 2021-07-06 19:57:04

    This document describes how to deploy Java Web projects on CentOS and is suitable for new individual users of Tencent Cloud.

    Software Version

    The versions of software tools used in this document are as follows, which may be different from your software versions during actual operations.

    • Operating system: CentOS 7.5
    • Tomcat: apache-tomcat-8.5.39
    • JDK: JDK 1.8.0_201

    Installing JDK

    After purchasing the CVM, you can click Login on the CVM details page to log in to your CVM instance where you can enter your username and password to set up the Java web environment. For more information on how to create a CVM instance, please see CVM - Creating Instance.

    Downloading JDK

    Enter the following command:

    mkdir /usr/java  # Create a `java` folder
    cd /usr/java     # Enter the `java` folder
    # Upload JDK installation package (recommended)
    You are recommended to use tools such as WinSCP to upload the JDK installation package to the above `java` folder and then decompress it.
    # Use a command (you are recommended to upload the installation package): run `wget` to download the package, which cannot be decompressed because a downloaded package declines the Oracle BSD License by default. Please go to https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html to accept the license agreement and obtain the download link with your cookies.
    wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie" https://download.oracle.com/otn-pub/java/jdk/8u201-b09/42970487e3af4f5aa5bca3f542482c60/jdk-8u201-linux-x64.tar.gz
    # Decompress
    chmod +x jdk-8u201-linux-x64.tar.gz
    tar -xzvf jdk-8u201-linux-x64.tar.gz

    Setting environmental variable

    1. Open the /etc/profile file.
      vi /etc/profile
    2. Press I to enter the editing mode and add the following information to the file.
      # set java environment
      export JAVA_HOME=/usr/java/jdk1.8.0_201
      export CLASSPATH=$JAVA_HOME/lib/tools.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib
      export PATH=$JAVA_HOME/bin:$PATH
    3. Press Esc to exit the editing mode and enter :wq to save and close the file.
    4. Load the environmental variable.
      source /etc/profile

    Viewing JDK installation result

    Run the java -version command. If the JDK version information is displayed, JDK has been successfully installed.

    Installing Tomcat

    Downloading Tomcat

    Enter the following commands:

    # The mirror address may change and the Tomcat version may be continuously upgraded. If the download link expired, please go to [Tomcat official website](https://tomcat.apache.org/download-80.cgi) and select an appropriate installation package address.
    wget http://mirrors.tuna.tsinghua.edu.cn/apache/tomcat/tomcat-8/v8.5.39/bin/apache-tomcat-8.5.39.tar.gz
    tar -xzvf apache-tomcat-8.5.39.tar.gz
    mv apache-tomcat-8.5.39 /usr/local/tomcat/

    The following files are in the /usr/local/tomcat/ directory:

    • bin: script file, which contains scripts for starting and stopping the Tomcat service.
    • conf: global configuration files, of which the most important ones are server.xml and web.xml.
    • webapps: the main web release directory in Tomcat, which is the default directory for storing web application files.
    • logs: Tomcat log files.

    If the download link expired, please replace it with the latest link at Tomcat's official website.

    Adding user

    # Add a general user `www` to run Tomcat
    useradd www
    # Create a website root directory
    mkdir -p /data/wwwroot/default
    # Upload the Java web project file (WAR package) to the website root directory and modify the file permission under the directory to `www`. This example shows how to create a Tomcat test page in the website root directory:
    echo Hello Tomcat! > /data/wwwroot/default/index.jsp
    chown -R www.www /data/wwwroot

    Setting JVM memory parameter

    1. Create a /usr/local/tomcat/bin/setenv.sh script file.
      vi /usr/local/tomcat/bin/setenv.sh
    2. Press I to enter the editing mode and add the following.
      JAVA_OPTS='-Djava.security.egd=file:/dev/./urandom -server -Xms256m -Xmx496m -Dfile.encoding=UTF-8'
    3. Press Esc to exit the editing mode and enter :wq to save and exit.

    Configuring server.xml

    1. Switch to the /usr/local/tomcat/conf/ directory.
      cd /usr/local/tomcat/conf/
    2. Back up the server.xml file.
      mv server.xml server_default.xml
    3. Create a new server.xml file.
      vi server.xml
    4. Press I to enter the editing mode and add the following.
      <?xml version="1.0" encoding="UTF-8"?>
      <Server port="8006" shutdown="SHUTDOWN">
      <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener"/>
      <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener"/>
      <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener"/>
      <Listener className="org.apache.catalina.core.AprLifecycleListener"/>
      <Resource name="UserDatabase" auth="Container"
      description="User database that can be updated and saved"
      <Service name="Catalina">
      <Connector port="8080"
      <Engine name="Catalina" defaultHost="localhost">
      <Realm className="org.apache.catalina.realm.LockOutRealm">
      <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
      <Host name="localhost" appBase="/data/wwwroot/default" unpackWARs="true" autoDeploy="true">
      <Context path="" docBase="/data/wwwroot/default" debug="0" reloadable="false" crossContext="true"/>
      <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
      prefix="localhost_access_log." suffix=".txt" pattern="%h %l %u %t &quot;%r&quot; %s %b" />
    5. Press Esc to exit the editing mode and enter :wq to save and exit.

    Starting Tomcat

    Method 1

    Enter the bin directory of the Tomcat server and run the ./startup.sh command to start the Tomcat server.

    cd /usr/local/tomcat/bin

    The execution result is as follows:

    Method 2

    1. Set up quick start, so that the Tomcat server can be started anywhere through service tomcat start.
      wget https://github.com/lj2007331/oneinstack/raw/master/init.d/Tomcat-init
      mv Tomcat-init /etc/init.d/tomcat
      chmod +x /etc/init.d/tomcat
    2. Run the following command and set the JAVA_HOME startup script.
      sed -i 's@^export JAVA_HOME=.*@export JAVA_HOME=/usr/java/jdk1.8.0_201@' /etc/init.d/tomcat
    3. Set auto-run.
      chkconfig --add tomcat
      chkconfig tomcat on
    4. Start Tomcat.
      # Start Tomcat
      service tomcat start
      # View Tomcat server status
      service tomcat status
      # Stop Tomcat
      service tomcat stop
      The execution result is as follows:
    5. If the system prompts that you have no permissions, switch to the root user and modify the permissions.
      cd /usr/local
      chmod -R 777 tomcat
    6. Enter http://public IP:port (where the port is the connector port set in server.xml) in the address bar of the browser. If the following page appears, the installation is successful.

    Configuring security group

    In case of access failure, check the security group. As shown in the above example, the connector port is 8080 in server.xml, so you need to open TCP:8080 to the internet in the security group bound to the corresponding CVM instance.

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