程式碼結構

第一步：新建一個介面

package com.chilly.handler;

import java.util.HashMap;
import java.util.Map;

/**
 * 業務處理公共的業務介面和業務分類
 */
public interface InterfaceHandler {

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

    public abstract String getCode();

    public abstract void setHandler();

    public abstract InterfaceHandler getHandler(String code);

    public abstract void handler(Object params);
}

第二步：建立一個抽象類實現預設處理業務
 

package com.chilly.handler;

import sun.awt.SunHints;

import javax.annotation.PostConstruct;

public class AbstractHanlderService implements InterfaceHandler{

    @Override
    public String getCode() {
        return "default";
    }

    /**
     *  PostConstruct註解，標識tomcat啟動完成時執行該方法
     * @return
     */
    @PostConstruct
    @Override
    public void setHandler() {
        handlerMap.put(getCode(),this);
    }

    @Override
    public InterfaceHandler getHandler(String code) {
        return handlerMap.get(code);
    }

    @Override
    public void handler(Object params) {
        System.out.println("預設處理業務");
    }
}

第三步：編寫其它業務處理邏輯
處理邏輯1

package com.chilly.handler.service;

import com.chilly.handler.AbstractHanlderService;

public class DeleteHandlerServiceImpl extends AbstractHanlderService {

    public String getCode() {
        return "delete";
    }

    @Override
    public void handler(Object params) {
        System.out.println("delete處理業務");
    }
}

處理邏輯2

package com.chilly.handler.service;

import com.chilly.handler.AbstractHanlderService;

public class UpdateHandlerServiceImpl extends AbstractHanlderService {

    public String getCode() {
        return "update";
    }

    @Override
    public void handler(Object params) {
        System.out.println("update處理業務");
    }
}

第四步：介面呼叫處理

package com.chilly.controller;

import com.chilly.handler.InterfaceHandler;
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) {
        InterfaceHandler handler = InterfaceHandler.handlerMap.get(code);
        handler.handler(request);
        return "handler ok";
    }

}

用到知識點：@PostConstruct