责任链模式

package com.test.chain;
import java.util.ArrayList;
import java.util.List;


public class BizFilterChain {
    /**
     * 执行器集合
     */
    public List<BizFilter> bizFilters;
    /**
     * 执行器下标
     */
    private int pos;
    public void addFilter(BizFilter bizFilter){
        this.bizFilters.add(bizFilter);
    }
    public BizFilterChain(){
        this.bizFilters = new ArrayList<>();
    }
    public void process(BizRequest request, BizResponse response){

      if (bizFilters.size() > pos) {
          BizFilter nextBizFilter = this.bizFilters.get(this.pos++);
          nextBizFilter.filter(request, response,this);
      }
    } 
}

 具体的处理器：

package com.test.chain;
public abstract class AbstractFilter implements BizFilter {
    @Override
    public void filter(BizRequest request, BizResponse response, BizFilterChain chain) {
        if (condition(request,response)) {
            this.doFilter(request, response, chain);
        }else {
            //此处为了继续执行下一个处理器，跟dofilter里的process作用一致
            chain.process(request,response);
        }
    }
    /**
     * 条件判断作为是否执行此filter的准入条件，具体子类需要实现
     * @param request
     * @param response
     * @return
     */
    public abstract boolean condition(BizRequest request, BizResponse response);

    /**
     * 子类的具体实现逻辑
     * @param request
     * @param response
     * @param chain
     */
    public abstract void doFilter(BizRequest request, BizResponse response, BizFilterChain chain);
}

public interface BizFilter {

    /**
     * 执行方法
     * @param request
     * @param response
     * @param chain
     */
    void filter(BizRequest request, BizResponse response,BizFilterChain chain);

}

/**
 * 具体的参数传递对象
 * @author chenwei
 * @date 2018/12/17 10:29
 * @Description
 */
public class BizRequest {
}

package com.test.chain;

/**
 * 结果返回对象
 * @author chenwei
 * @date 2018/12/17 10:29
 * @Description
 */
public class BizResponse {
}

package com.test.chain;

/**
 * @author chenwei
 * @date 2018/12/17 10:30
 * @Description
 */
public class Demo1Filter extends AbstractFilter {
    @Override
    public void doFilter(BizRequest request, BizResponse response,BizFilterChain chain) {

        System.out.println("demo1 已经处理过");
        //执行这个是为了能继续执行下一个filter，如果想直接返回的话，结束执行，则直接return，不执行process方法
        chain.process(request, response);
    }

    @Override
    public boolean condition(BizRequest request, BizResponse response) {
        return true;
    }
}

package com.test.chain;

/**
 * @author chenwei
 * @date 2018/12/17 10:30
 * @Description
 */
public class Demo2Filter extends AbstractFilter {
    @Override
    public boolean condition(BizRequest request, BizResponse response) {
        return true;
    }

    @Override
    public void doFilter(BizRequest request, BizResponse response,BizFilterChain chain) {
        System.out.println("demo2 已经处理过");
        chain.process(request,response);
    }

}

package com.test.chain;

/**
 * @author chenwei
 * @date 2018/12/17 10:30
 * @Description
 */
public class Demo3Filter extends AbstractFilter {
    @Override
    public boolean condition(BizRequest request, BizResponse response) {
        return true;
    }
    @Override
    public void doFilter(BizRequest request, BizResponse response,BizFilterChain chain) {
        System.out.println("demo3 已经处理过");
        chain.process(request,response);
    }
}

package com.test.chain;

/**
 * @author chenwei
 * @date 2018/12/17 10:42
 * @Description
 */
public class BizExecuter {


    public static void main(String[] args) {
        Demo1Filter demo1 = new Demo1Filter();
        Demo2Filter demo2 = new Demo2Filter();
        Demo3Filter demo3 = new Demo3Filter();

        BizFilterChain chain = new BizFilterChain();

        chain.addFilter(demo1);
        chain.addFilter(demo2);
        chain.addFilter(demo3);
        BizRequest request = new BizRequest();
        BizResponse response = new BizResponse();
        chain.process(request, response);
    }
}