java设计模式——命令模式-优快云博客

本文通过一个具体实例详细介绍了命令模式的设计原理及其在Java中的实现方式。文章展示了如何通过定义Command接口来解耦请求发送者和接收者，并通过Invoker类来调度这些请求。这种模式常见于Struts等框架中。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

《大话设计模式》第二十三章

package ch23;

public class Receiver {
	public void action() {
		System.out.println("执行请求");
	}
}

package ch23;

public abstract class Command {
	protected Receiver receiver;

	public Command(Receiver receiver) {
		this.receiver = receiver;
	}
	
	public abstract void execute();
}

package ch23;

public class ConcreteCommandA extends Command {

	public ConcreteCommandA(Receiver receiver) {
		super(receiver);
	}

	@Override
	public void execute() {
		receiver.action();
	}

}

package ch23;

public class ConcreteCommandB extends Command {

	public ConcreteCommandB(Receiver receiver) {
		super(receiver);
	}

	@Override
	public void execute() {
		receiver.action();
	}

}

package ch23;

public class ConcreteCommandC extends Command {

	public ConcreteCommandC(Receiver receiver) {
		super(receiver);
	}

	@Override
	public void execute() {
		receiver.action();
	}

}

package ch23;

public class Invoker {
	private Command command;

	public void setCommand(Command command) {
		this.command = command;
	}
	
	public void executeCommand() {
		command.execute();
	}
}

package ch23;

import java.util.ArrayList;
import java.util.List;

/**
 * 命令模式
 * @author Administrator
 *
 */
public class Client {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Receiver r = new Receiver();
		Command ca = new ConcreteCommandA(r);
		Command cb = new ConcreteCommandB(r);
		Command cc = new ConcreteCommandC(r);
		List<Command> commandList = new ArrayList<Command>();
		commandList.add(ca);
		commandList.add(cb);
		commandList.add(cc);
		Invoker in = new Invoker();
		for (int i = 0; i < commandList.size(); i++) {
			in.setCommand(commandList.get(i));
			in.executeCommand();
		}
	}

}

命令模式在struts里用的很多，一个action就是一个command。