拦截过滤模式
拦截过滤器模式（Intercepting Filter Pattern）用于对应用程序的请求或响应做一些预处理/后处理。定义过滤器，并在把请求传给实际目标应用程序之前应用在请求上。过滤器可以做认证/授权/记录日志，或者跟踪请求，然后把请求传给相应的处理程序。以下是这种设计模式的实体。
- 过滤器（Filter）
过滤器在请求处理程序执行请求之前或之后，执行某些任务。
- 过滤器链（Filter Chain）
过滤器链带有多个过滤器，并在 Target 上按照定义的顺序执行这些过滤器。
实际案例
类信息概览：
| 类名 | 说明 |
|---|---|
| Main.java | 方法的总入口 |
| FilterChain.java | 过滤器链 |
| ValidFilter.java | 校验过滤 |
| AuthFilter.java | 验证过滤 |
| Filter.java | 过滤接口 |
定义
- FilterChain.java
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
* Copyright (c) 2012-2018. houbinbini Inc.
* design-pattern All rights reserved.
*/
package com.ryo.design.pattern.note.interceptingFilter;
import java.util.ArrayList;
import java.util.List;
/**
* <p> </p>
*
* <pre> Created: 2018/5/29 下午5:24 </pre>
* <pre> Project: design-pattern </pre>
*
* @author houbinbin
* @version 1.0
* @since JDK 1.7
*/
public class FilterChain implements Filter {
private List<Filter> filterList = new ArrayList<>();
public FilterChain addFilter(Filter filter) {
filterList.add(filter);
return this;
}
@Override
public Filter filter(String info) {
for(Filter filter : this.filterList) {
filter.filter(info);
}
return this;
}
}
- ValidFilter.java
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
* Copyright (c) 2012-2018. houbinbini Inc.
* design-pattern All rights reserved.
*/
package com.ryo.design.pattern.note.interceptingFilter;
/**
* <p> </p>
*
* <pre> Created: 2018/5/29 下午5:22 </pre>
* <pre> Project: design-pattern </pre>
*
* @author houbinbin
* @version 1.0
* @since JDK 1.7
*/
public class ValidFilter implements Filter {
@Override
public Filter filter(String info) {
System.out.println("[Valid]: "+info);
return this;
}
}
- AuthFilter.java
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
* Copyright (c) 2012-2018. houbinbini Inc.
* design-pattern All rights reserved.
*/
package com.ryo.design.pattern.note.interceptingFilter;
/**
* <p> 权限过滤器 </p>
*
* <pre> Created: 2018/5/29 下午5:22 </pre>
* <pre> Project: design-pattern </pre>
*
* @author houbinbin
* @version 1.0
* @since JDK 1.7
*/
public class AuthFilter implements Filter {
@Override
public Filter filter(String info) {
System.out.println("[Auth]: "+info);
return this;
}
}
- Filter.java
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
* Copyright (c) 2012-2018. houbinbini Inc.
* design-pattern All rights reserved.
*/
package com.ryo.design.pattern.note.interceptingFilter;
/**
* <p> </p>
*
* <pre> Created: 2018/5/29 下午5:22 </pre>
* <pre> Project: design-pattern </pre>
*
* @author houbinbin
* @version 1.0
* @since JDK 1.7
*/
public interface Filter {
/**
* 执行过滤信息
* @param info 原始信息
* @return 过滤器本身
*/
Filter filter(final String info);
}
测试
- Main.java
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
* Copyright (c) 2012-2018. houbinbini Inc.
* design-pattern All rights reserved.
*/
package com.ryo.design.pattern.note.interceptingFilter;
/**
* <p> </p>
*
* <pre> Created: 2018/5/29 下午5:20 </pre>
* <pre> Project: design-pattern </pre>
*
* @author houbinbin
* @version 1.0
* @since JDK 1.7
*/
public class Main {
public static void main(String[] args) {
FilterChain filterChain = new FilterChain();
filterChain.addFilter(new AuthFilter())
.addFilter(new ValidFilter());
filterChain.filter("filtered info");
}
}
- 测试结果
[Auth]: filtered info
[Valid]: filtered info
实现方式
UML & Code
UML
UML 图示如下
Code
代码地址
