深入理解Java责任链模式实现灵活的请求处理流程

public enum RequestType {
    TYPE_A,
    TYPE_B
}

@Data
public class Request {
    private RequestType requestType;
    private String content;
    public Request(RequestType requestType, String content) {
        this.requestType = requestType;
        this.content = content;
    }
}

@Data
public abstract class Handler {
    protected Handler nextHandler;
    /**
     * 处理请求的方法
     *
     * @param request
     */
    public abstract void handle(Request request);
}

public class ConcreteHandlerA extends Handler {
    /**
     * 处理请求的方法
     *
     * @param request
     */
    @Override
    public void handle(Request request) {
        if (request.getRequestType() == RequestType.TYPE_A) {
            // 处理请求
            System.out.println("ConcreteHandlerA 处理了请求:" + request.getContent());
        }else {
            // 将请求传递给下一个处理器
            if (nextHandler != null){
                nextHandler.handle(request);
            }
        }
    }
}
public class ConcreteHandlerB extends Handler{
    /**
     * 处理请求的方法
     *
     * @param request
     */
    @Override
    public void handle(Request request) {
        if (request.getRequestType() == RequestType.TYPE_B) {
            // 处理请求
            System.out.println("ConcreteHandlerB 处理了请求:" + request.getContent());
        }else {
            // 将请求传递给下一个处理器
            if (nextHandler != null){
                nextHandler.handle(request);
            }
        }
    }
}	

public class Demo {
    public static void main(String[] args) {
        // 创建责任链
        Handler handlerA = new ConcreteHandlerA();
        Handler handlerB = new ConcreteHandlerB();
        handlerA.setNextHandler(handlerB);
        // 发送请求
        Request request1 = new Request(RequestType.TYPE_A,"请求A");
        handlerA.handle(request1);
        Request request2 = new Request(RequestType.TYPE_B,"请求B");
        handlerA.handle(request2);
        Request request3 = new Request(RequestType.TYPE_A,"请求C");
        handlerA.handle(request3);
    }
}