Operations and deployment technology in Java

Java is a programming language widely used in enterprise-level application development and occupies an extremely important position in enterprise-level application systems. However, just writing Java code is not enough. In an actual production environment, Java programs also need to go through a series of operation, maintenance and deployment operations before they can truly exert their value. This article will introduce some operation and maintenance and deployment technologies in Java, aiming to help Java programmers better manage the system, thereby improving the stability and performance of Java programs in the production environment.

1. Service management

It is very important to manage services in a production environment. Service management includes operations such as starting services, stopping services, and restarting services. For Java applications, you can use the command line tool of the Java virtual machine to manage services.

1. JVM (Java Virtual Machine) command line tool

The JVM command line tool provides a series of options that can be used to start, stop and restart Java services. Commonly used commands include:

Start the service: java -jar test.jar

Stop the service: Ctrl C or kill -9 PID

Restart the service:

kill -15 PID
java -jar test.jar

Among them, test.jar represents the Jar package of the program, and PID represents the process ID.

In addition, you can also use the following command line parameters to manage services:

-Xms: 指定 JVM 的初始化堆空间。 
-Xmx: 指定 JVM 的最大堆空间。 
-XX:PermSize: 指定 JVM 的初始持久代大小。 
-XX:MaxPermSize: 指定 JVM 的最大持久代大小。 
-Dproperty=value: 定义系统属性。 

By setting these command line parameters, you can optimize the performance and stability of Java programs.

2. Daemon process

Sometimes, we need to automatically start the service when the server starts. At this time, we can use the daemon process to achieve this. Daemons are processes that run in the background and can be started automatically when the system starts. Commonly used daemon tools include Systemd and systemctl.

• Systemd

Systemd is a system and service manager used to start, stop and manage services on Linux platforms. You can set the service to start automatically after it runs successfully.

• systemctl

systemctl is a front-end tool for Systemd, used to manage the status of system and service processes. You can use systemctl to start, stop or restart services.

2. Automated deployment

In a production environment, each deployment requires many manual operations, which will greatly reduce the efficiency of deployment and increase the possibility of errors. Therefore, automated deployment becomes very important.

In Java, we can use some automation tools, such as Ansible, Puppet and Chef, to achieve automated deployment and configuration. These tools provide mechanisms, such as automation modules, task scripts, and configuration management modules, to help programmers simplify the process of automated deployment.

3. Monitoring and logging

In the actual production environment, it is very important to understand and solve various problems in a timely manner. Therefore, monitoring and logging are essential features for Java programs in a production environment.

1. Monitoring

Monitoring of Java programs is very important. Through monitoring, you can know the status of Java programs in a timely manner, such as CPU usage, memory usage, network connection status, etc., so that you can solve problems and adjust programs in a timely manner. In Java, commonly used monitoring tools include JConsole, JVisualVM and Zabbix.

2. Log

The log of Java program is very important. Through logs, we can know what events occurred in the program at a certain moment, so as to better understand the behavior and running status of the program. In Java, commonly used logging frameworks include log4j, slf4j and logback. These log frameworks support multiple logging methods such as file logs, syslog, and database logs, and provide rich log levels and filters so that programmers can better manage and maintain logs.

Summary

Java occupies an extremely important position in enterprise-level application systems. In a production environment, the operation, maintenance and deployment technology of Java programs are crucial. This article introduces some operation and maintenance and deployment technologies in Java, such as service management, automated deployment, monitoring and logging, etc. It is hoped that these technologies can help Java programmers better manage the system and ensure the stability and performance of Java programs in the production environment.

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