设计模式学习笔记--前端控制器模式

三十、前端控制器模式

前端控制器模式(Front Controller Pattern),主要用于集中统一化对外的请求接口，便于更好的封装内部逻辑。

实现

创建不同的View视图类

HomeView

,

StudnetView

，模拟不同的请求反馈，创建一个前端控制器类，

FrontController

，一个逻辑分发类

Dispatcher

。



View视图类

HomeView.java

package patterns.front;

/**
* Created by lenovo on 2016/12/12 0012.
* 创建视图类
*/
public class HomeView {
public void show(){
System.out.println("显示Home主页");
}
}

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StudentView.java

package patterns.front;

/**
* Created by lenovo on 2016/12/12 0012.
* 创建视图类
*/
public class StudentView {
public void show(){
System.out.println("Student 页面");
}
}

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分发类

Dispatcher.java

package patterns.front;

/**
* Created by lenovo on 2016/12/12 0012.
* 调度器，用于分配请求
*/
public class Dispatcher {
private HomeView homeView;
private StudentView studentView;

public Dispatcher() {
studentView = new StudentView();
homeView = new HomeView();
}

public void dispatch(String request){
if (request.equalsIgnoreCase("student")){
studentView.show();
}else {
homeView.show();
}
}
}

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前端控制器类

FrontController.java

package patterns.front;

/**
* Created by lenovo on 2016/12/12 0012.
* 前端控制器，统一接收请求。
*/
public class FrontController {
private Dispatcher dispatcher;

public FrontController() {
dispatcher = new Dispatcher();
}
private boolean isAuthenticUser(){
System.out.println("User is authenticated successfully .");
return true;
}

private void trackRequest(String request){
System.out.println("请求页面： "+request);
}

public void  dispatchRequest(String request){
//记录请求
trackRequest(request);
//校验用户
if (isAuthenticUser()){
dispatcher.dispatch(request);
}
}
}

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演示

FrontControllerPatternDemo.java

package patterns.front;

/**
* Created by lenovo on 2016/12/12 0012.
* 演示
*/
public class FrontControllerPatternDemo {
public static  void main(String[] args){
FrontController controller = new FrontController();

controller.dispatchRequest("HOME");
controller.dispatchRequest("student");
}
}

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输出

请求页面： HOME
User is authenticated successfully .
显示Home主页
请求页面： student
User is authenticated successfully .
Student 页面