设计模式之单例模式简单例子(Java)_单例模式简单实例java含类图和运行结果-优快云博客

本文链接：https://blog.youkuaiyun.com/gsnet/article/details/8614271

本文介绍了一个使用Java实现的单例模式配置类MachineConfig，该类用于存储服务器的IP地址和端口号，并提供了获取和设置这些参数的方法。

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package com.stephen.javatest02;

public class MachineConfig {
   private static MachineConfig a = null;
   private String ServerIP="";
   private int ServerPort=0;

   private MachineConfig()
   {
   }

   public String getServerIp()
   {
       return this.ServerIP;
   }

   public int getServerPort()
   {
       return this.ServerPort;
   }


   public synchronized void setServerParam(String ServerIP, int ServerPort)
   {
       this.ServerIP = ServerIP;
       this.ServerPort = ServerPort;
   }

   public static synchronized MachineConfig getInstance()
   {
       if(null == a)
           a = new MachineConfig();
       return a;
   }
}

调用方法：
        MachineConfig mc = MachineConfig.getInstance();
        mc.setServerParam("172.16.24.19", 8080);
        System.out.println("server ip:" + mc.getServerIp());
        System.out.println("server port:" + mc.getServerPort());

        MachineConfig mc2 = MachineConfig.getInstance();
        mc2.setServerParam("192.168.1.1", 6981);
        System.out.println("server ip:" + mc.getServerIp());
        System.out.println("server port:" + mc.getServerPort());

运行结果：
server ip:172.16.24.19
server port:8080
server ip:192.168.1.1
server port:6981