Java Install

1) 安装OpenJDK 8
[root@srv1 ~]# yum install java-1.8.0-openjdk java-1.8.0-openjdk-devel -y

[root@srv1 ~]# cat > /etc/profile.d/java8.sh << 'EOF'
export JAVA_HOME=$(dirname $(dirname $(readlink $(readlink $(which javac)))))
export PATH=\$PATH:\$JAVA_HOME/bin
export CLASSPATH=.:\$JAVA_HOME/jre/lib:\$JAVA_HOME/lib:\$JAVA_HOME/lib/tools.jar
EOF

[root@srv1 ~]# source /etc/profile.d/java8.sh

2) 验证OpenJDK 8
[root@srv1 ~]# java -version
openjdk version "1.8.0_262"
OpenJDK Runtime Environment (build 1.8.0_262-b10)
OpenJDK 64-Bit Server VM (build 25.262-b10, mixed mode)

[root@srv1 ~]# cat > java_test.java <<'EOF'
class java_test {
    public static void main(String[] args) {
        System.out.println("Hello Java World !");
    }
}
EOF

[root@srv1 ~]# javac java_test.java
[root@srv1 ~]# java java_test
Hello Java World !

3) 如果有多个OpenJDK版本,可切换至OpenJDK 8
[root@srv1 ~]# alternatives --config java


There is 1 program that provides 'java'.


  Selection    Command
-----------------------------------------------
*+ 1           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.262.b10-0.el8_2.x86_64/jre/bin/java)


Enter to keep the current selection[+], or type selection number: 1

1) 安装OpenJDK 11
[root@srv1 ~]# yum install java-11-openjdk java-11-openjdk-devel -y

[root@srv1 ~]# cat > /etc/profile.d/java11.sh << 'EOF'
export JAVA_HOME=$(dirname $(dirname $(readlink $(readlink $(which javac)))))
export PATH=\$PATH:\$JAVA_HOME/bin
EOF

[root@srv1 ~]# source /etc/profile.d/java11.sh

2) 验证OpenJDK 11
[root@srv1 ~]# java --version
openjdk 11.0.8 2020-07-14 LTS
OpenJDK Runtime Environment 18.9 (build 11.0.8+10-LTS)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.8+10-LTS, mixed mode, sharing)

[root@srv1 ~]# cat > java_test.java <<'EOF'
class java_test {
    public static void main(String[] args) {
        System.out.println("Hello Java World !");
    }
}
EOF

[root@srv1 ~]# javac java_test.java
[root@srv1 ~]# java java_test
Hello Java World !

3) 如果有多个OpenJDK版本,可切换至OpenJDK 11
[root@srv1 ~]# alternatives --config java


There is 1 program that provides 'java'.


  Selection    Command
-----------------------------------------------
*+ 1           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.8.10-0.el8_2.x86_64/bin/java)


Enter to keep the current selection[+], or type selection number: 1

1) 安装好Open JDK
2) 下载Tomcat 9
[root@srv1 ~]# curl -O https://mirrors.tuna.tsinghua.edu.cn/apache/tomcat/tomcat-9/v9.0.37/bin/apache-tomcat-9.0.37.tar.gz

[root@srv1 ~]# tar xfz apache-tomcat-9.0.37.tar.gz

[root@srv1 ~]# mv apache-tomcat-9.0.37 /usr/libexec/tomcat9
[root@srv1 ~]# useradd -M -d /usr/libexec/tomcat9 tomcat
[root@srv1 ~]# chown -R tomcat. /usr/libexec/tomcat9

3) 制作启动服务文件
[root@srv1 ~]# vim /usr/lib/systemd/system/tomcat9.service
[Unit]
Description=Apache Tomcat 9
After=network.target


[Service]
Type=oneshot
ExecStart=/usr/libexec/tomcat9/bin/startup.sh
ExecStop=/usr/libexec/tomcat9/bin/shutdown.sh
RemainAfterExit=yes
User=tomcat
Group=tomcat


[Install]
WantedBy=multi-user.target

[root@srv1 ~]# systemctl enable --now tomcat9
Created symlink /etc/systemd/system/multi-user.target.wants/tomcat9.service → /usr/lib/systemd/system/tomcat9.service.

[root@srv1 ~]# systemctl is-active tomcat9
active

4) SELinux设定
[root@srv1 ~]# vim catalinash.te
module catalinash 1.0;


require {
        type init_t;
        type admin_home_t;
        class file { append execute execute_no_trans ioctl open read };
}


#============= init_t ==============
allow init_t admin_home_t:file { append execute execute_no_trans ioctl open read };

[root@srv1 ~]# checkmodule -m -M -o catalinash.mod catalinash.te
checkmodule: loading policy configuration from zabbix_server.te
checkmodule: policy configuration loaded
checkmodule: writing binary representation (version 19) to catalinash.mod

[root@srv1 ~]# semodule_package --outfile catalinash.pp --module catalinash.mod
[root@srv1 ~]# semodule -i catalinash.pp

5) Firewall设定
[root@srv1 ~]# firewall-cmd --add-port=8080/tcp --permanent
success
[root@srv1 ~]# firewall-cmd --reload
success

6) 访问Tomcat
[浏览器]===>http://$srv-ip:8080


7) 创建测试程序
[root@srv1 ~]# mkdir /usr/libexec/tomcat9/webapps/ROOT/WEB-INF/classes
[root@srv1 ~]# chown tomcat. /usr/libexec/tomcat9/webapps/ROOT/WEB-INF/classes
[root@srv1 ~]# cd /usr/libexec/tomcat9/webapps/ROOT/WEB-INF/classes
[root@srv1 classes]# vim daytime.java
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.Calendar;


public class daytime extends HttpServlet {
    public void doGet(HttpServletRequest request
    ,HttpServletResponse response)


    throws IOException, ServletException{
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        Calendar cal = Calendar.getInstance();
        out.println("<html>\n<head>\n<title>DayTime</title>\n</head>\n<body>");
        out.println("<div style=\"font-size: 40px; text-align: center; font-weight: bold\">");
        out.println(cal.get(Calendar.YEAR) + "/" + (cal.get(Calendar.MONTH) + 1) + "/" + 
        cal.get(Calendar.DATE) + " " + cal.get(Calendar.HOUR_OF_DAY) + ":" + cal.get(Calendar.MINUTE));
        out.println("</div>\n</body>\n</html>");
    }
}

[root@srv1 classes]# javac -classpath /usr/libexec/tomcat9/lib/servlet-api.jar daytime.java

[root@srv1 classes]# vim /usr/libexec/tomcat9/webapps/ROOT/WEB-INF/web.xml
# 于<web-app> = </web-app>区段之间追加如下内容
  <servlet>
     <servlet-name>daytime</servlet-name>
     <servlet-class>daytime</servlet-class>
  </servlet>
  <servlet-mapping>
     <servlet-name>daytime</servlet-name>
     <url-pattern>/daytime</url-pattern>
  </servlet-mapping>

7) 访问Tomcat测试程序
[浏览器]===>http://$srv-ip:8080/daytime



8) 结合Apache
(1) 开启Tomcat 8009端口
[root@tomcat ~]# vim /usr/libexec/tomcat9/conf/server.xml
# 于122行,添加如下内容
    <Connector address="::" port="8009" protocol="AJP/1.3" redirectPort="8443" secretRequired=""/>

[root@tomcat ~]# systemctl restart tomcat9

(2) 配置Apache
[root@srv1 ~]# yum install httpd -y

[root@srv1 ~]# vim /etc/httpd/conf.d/proxy_ajp.conf
ProxyPass /tomcat9/ ajp://localhost:8009/

[root@srv1 ~]# systemctl enable --now httpd

(3) 访问Apache
[浏览器]===>http://$srv-ip/tomcat9/  # 定要在最后的tomcat9后面增加"/"符号



[浏览器]===>http://$srv-ip/tomcat9/daytime