抽象Handler

package com.yimin.handler;

import com.yimin.dto.Ctx;

public abstract class AbsHandler {
    private AbsHandler next;

    public void execute(Ctx ctx) {
        ctx = handle(ctx);
        if (hasNext()) {
            next.execute(ctx);
        }
    }

    public abstract Ctx handle(Ctx ctx);

    public void next(AbsHandler next) {
        this.next = next;
    }

    public boolean hasNext() {
        return next != null;
    }

}

具体Handler

package com.yimin.handler;

import com.yimin.dto.Ctx;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Order(1)
@Component
public class FirstHandler extends AbsHandler {
    @Override
    public Ctx handle(Ctx ctx) {
        System.out.println("first do");
        // update ctx
        return ctx;
    }
}

package com.yimin.handler;

import com.yimin.dto.Ctx;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Order(2)
@Component
public class SecondHandler extends AbsHandler {
    @Override
    public Ctx handle(Ctx ctx) {
        System.out.println("second do");
        // update ctx
        return ctx;
    }
}

package com.yimin.handler;

import com.yimin.dto.Ctx;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Order(3)
@Component
public class ThirdHandler extends AbsHandler {
    @Override
    public Ctx handle(Ctx ctx) {
        System.out.println("third do");
        // update ctx
        return ctx;
    }
}

Ctx就是一个上下文对象，根据业务做相应修改

package com.yimin.dto;

public class Ctx {
}

Test

@SpringBootTest
class DemoApplicationTests {

    @Autowired
    private List<AbsHandler> chains;

    @Test
    void testOrderHandler() {
         // 实际上不用排序，@Order已经决定了顺序
        chains.sort(AnnotationAwareOrderComparator.INSTANCE);
        for (int i = 0; i < chains.size(); i++) {
            if (i == chains.size() - 1) {
                chains.get(i).next(null);
            } else {
                chains.get(i).next(chains.get(i + 1));
            }
        }
        chains.get(0).execute(new Ctx());
    }

}

执行结果

first do
second do
third do