java设计模式-用接口和自定义注解实现

代码结构

 

 

第一步：创建接口

package com.chilly.handler.service;

/**
 * 业务处理公共的业务接口和业务分类
 */
public interface HandlerService {

    public abstract void handler(Object params);
}

第二步：创建实现类
业务处理类1

package com.chilly.handler.service.impl;

import com.chilly.annotation.DBtype;
import com.chilly.handler.service.HandlerService;
import org.springframework.stereotype.Service;

@DBtype(code = "update")
@Service
public class UpdateHandlerServiceImpl implements HandlerService {

    @Override
    public void handler(Object params) {
        System.out.println("update处理业务");
    }
}

业务处理类2

package com.chilly.handler.service.impl;

import com.chilly.annotation.DBtype;
import com.chilly.handler.service.HandlerService;
import org.springframework.stereotype.Service;


@DBtype(code = "delete")
@Service

public class DeleteHandlerServiceImpl implements HandlerService {

    @Override
    public void handler(Object params) {
        System.out.println("delete处理业务");
    }
}

第三步：工具类

package com.chilly.utils;

import com.chilly.annotation.DBtype;
import com.chilly.handler.service.HandlerService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;

import javax.annotation.PostConstruct;
import java.util.HashMap;
import java.util.Map;

@Component
public class IHandlerUtils {

    @Autowired
    private ApplicationContext applicationContext;

    public static final Map<String, HandlerService> handlerMap = new HashMap<>();

    @PostConstruct
    private void initHandler(){
        Map<String, HandlerService> handlerServiceMap = applicationContext.getBeansOfType(HandlerService.class);
        if(handlerServiceMap != null && handlerServiceMap.size() > 0){
            for(HandlerService handlerService : handlerServiceMap.values()){
                inintAnnotation(handlerService);
            }
        }

    }

    private void inintAnnotation(HandlerService handlerService){
        DBtype dBtype = handlerService.getClass().getAnnotation(DBtype.class);
        if(dBtype != null && !StringUtils.isEmpty(dBtype.code())){
            handlerMap.put(dBtype.code(),handlerService);
        }
    }


    public static HandlerService getHandlerService(String code){
        return handlerMap.get(code);
    }


}

第四步：controller控制器

package com.chilly.controller;

import com.chilly.handler.service.HandlerService;
import com.chilly.utils.IHandlerUtils;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletRequest;

@RestController
public class HandlerController {

    @PostMapping("/handler")
    public String test(String code, HttpServletRequest request) {
        HandlerService handler = IHandlerUtils.getHandlerService(code);
        handler.handler(request);
        return "handler ok";
    }

}
第五步：postMan调用

 

 http://localhost:8989/handler?code=delete

 

知识点：

 1、获取ApplicationContext

https://blog.csdn.net/weixin_38361347/article/details/89304414

2、自定义注解

3、@PostConstruct