Java 策略模式與模板方法模式相關(guān)總結(jié)

更新時間：2021年01月30日 09:49:52 作者：廢物大師兄

這篇文章主要介紹了Java 策略模式與模板方法模式相關(guān)總結(jié)，幫助大家更好的理解和使用Java，感興趣的朋友可以了解下

1. 策略模式

策略模式是一種行為設(shè)計(jì)模式，它能讓你定義一系列算法，并將每種算法分別放入獨(dú)立的類中，以使算法的對象能夠相互替換。

當(dāng)你有許多僅在執(zhí)行某些行為時略有不同的相似類時，可使用策略模式。使用該模式能將類的業(yè)務(wù)邏輯與其算法實(shí)現(xiàn)細(xì)節(jié)隔離開來。

說白了，其實(shí)還是解耦

策略模式的結(jié)構(gòu)如上圖所示，主要包含三個角色：

抽象角色：通常是一個接口
具體角色：接口的具體實(shí)現(xiàn)
環(huán)境角色：調(diào)用接口的上下文環(huán)境，通常是一段業(yè)務(wù)邏輯方法

舉個常見的例子：支付

先定義一個接口 PayStrategy.java

package com.example.service;

import com.example.domain.dto.PayDTO;
import com.example.domain.dto.PayDetailDTO;

/**
 * @author ChengJianSheng
 * @date 2021/1/11
 */
public interface PayStrategy {

  /**
   * 下單
   */
  PayDTO prepay();

  /**
   * 查詢
   */
  PayDetailDTO query();

  /**
   * 撤銷
   */
  void cancel();

  /**
   * 退款
   */
  void refund();

}

然后是具體實(shí)現(xiàn)

AlipayStrategy.java

package com.example.service.impl;

import com.alipay.api.AlipayClient;
import com.alipay.api.request.AlipayTradePrecreateRequest;
import com.alipay.api.response.AlipayTradeCancelResponse;
import com.example.domain.dto.PayDTO;
import com.example.domain.dto.PayDetailDTO;
import com.example.service.PayStrategy;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

/**
 * https://opendocs.alipay.com/open/common/abilitymap
 * https://opendocs.alipay.com/open/194/106078
 * 掃碼支付
 */
@Component
public class AlipayStrategy implements PayStrategy {

  @Autowired
  private AlipayClient alipayClient;

  @Override
  public PayDTO prepay() {
    AlipayTradePrecreateRequest request = new AlipayTradePrecreateRequest();
    AlipayTradeCancelResponse response = alipayClient.execute(request);
    return null;
  }

  @Override
  public PayDetailDTO query() {
    return null;
  }

  @Override
  public void cancel() {

  }

  @Override
  public void refund() {

  }

  public void payNotify(String data) {

  }

  public void refundNotify() {

  }
}

WeixinPayStrategy.java

package com.example.service.impl;

import com.example.domain.dto.PayDTO;
import com.example.domain.dto.PayDetailDTO;
import com.example.service.PayStrategy;
import com.github.binarywang.wxpay.bean.notify.WxPayOrderNotifyResult;
import com.github.binarywang.wxpay.bean.request.WxPayOrderQueryRequest;
import com.github.binarywang.wxpay.bean.request.WxPayUnifiedOrderRequest;
import com.github.binarywang.wxpay.service.WxPayService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

/**
 * https://pay.weixin.qq.com/wiki/doc/apiv3/wxpay/pages/index.shtml
 * https://github.com/Wechat-Group/WxJava/wiki/%E5%BE%AE%E4%BF%A1%E6%94%AF%E4%BB%98
 * @author ChengJianSheng
 * @date 2021/1/11
 */
@Component
public class WeixinPayStrategy implements PayStrategy {

  @Autowired
  private WxPayService wxPayService;

  @Override
  public PayDTO prepay() {
    WxPayUnifiedOrderRequest request = new WxPayUnifiedOrderRequest();
    wxPayService.createOrder(request);
    return null;
  }

  @Override
  public PayDetailDTO query() {
    WxPayOrderQueryRequest request = new WxPayOrderQueryRequest();
    wxPayService.queryOrder(request);
    return null;
  }

  @Override
  public void cancel() {

  }

  @Override
  public void refund() {

  }

  public void payNotify(String data) {
    WxPayOrderNotifyResult result = wxPayService.parseOrderNotifyResult(data);
  }

  public void refundNotify(String data) {
    WxPayOrderNotifyResult result = wxPayService.parseRefundNotifyResult(data);
  }
}

上下文

package com.example.service.impl;

import com.example.domain.dto.PayDTO;
import com.example.service.PayService;
import com.example.service.PayStrategy;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

/**
 * @author ChengJianSheng
 * @date 2021/1/11
 */
@Service
public class PayServiceImpl implements PayService {
  @Autowired
  private AlipayStrategy alipayStrategy;
  @Autowired
  private WeixinPayStrategy weixinPayStrategy;

  @Override
  public void prePay(PayDTO payDTO) {
    // 創(chuàng)建支付訂單
    // 組裝參數(shù)
    PayStrategy payStrategy = null;
    if (payDTO.getChannel() == 1) {
      payStrategy = alipayStrategy;
    } else {
      payStrategy = weixinPayStrategy;
    }

    payStrategy.prepay();

  }
}

這樣就將算法的細(xì)節(jié)與業(yè)務(wù)邏輯隔離開，開發(fā)始終要遵循的原則是：高內(nèi)聚，低耦合

其余部分代碼補(bǔ)充如下：

pom.xml

<dependency>
  <groupId>com.alipay.sdk</groupId>
  <artifactId>alipay-sdk-java</artifactId>
  <version>4.11.8.ALL</version>
</dependency>
<dependency>
  <groupId>com.github.binarywang</groupId>
  <artifactId>weixin-java-pay</artifactId>
  <version>4.0.0</version>
</dependency>

AlipayConfig.java

package com.example.config;

import com.alipay.api.AlipayClient;
import com.alipay.api.DefaultAlipayClient;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * 掃碼支付
 * https://opendocs.alipay.com/open/194/106078
 * https://opendocs.alipay.com/open/common/abilitymap
 *
 * @author ChengJianSheng
 * @date 2021/1/11
 */
@Configuration
public class AlipayConfig {
  @Value("${alipay.appId}")
  private String appId;
  @Value("${alipay.privateKey}")
  private String privateKey;
  @Value("${alipay.publicKey}")
  private String publicKey;

  @Bean
  public AlipayClient alipayClient() {
    AlipayClient alipayClient = new DefaultAlipayClient("https://openapi.alipay.com/gateway.do", appId, privateKey, "json", "UTF-8", publicKey, "RSA2");
    return alipayClient;
  }
}

WeixinPayConfig.java

package com.example.config;

import com.github.binarywang.wxpay.config.WxPayConfig;
import com.github.binarywang.wxpay.service.WxPayService;
import com.github.binarywang.wxpay.service.impl.WxPayServiceImpl;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * https://pay.weixin.qq.com/wiki/doc/apiv3/index.shtml
 * https://github.com/Wechat-Group/WxJava/wiki/%E5%BE%AE%E4%BF%A1%E6%94%AF%E4%BB%98
 * @author ChengJianSheng
 * @date 2021/1/11
 */
@Configuration
public class WeixinPayConfig {
  /**
   * 公眾號appid
   */
  @Value("${weixin.pay.appId}")
  private String appId;
  /**
   * 商戶號.
   */
  @Value("${weixin.pay.mchId}")
  private String mchId;
  /**
   * 商戶密鑰.
   */
  @Value("${weixin.pay.mchKey}")
  private String mchKey;

  @Value("${weixin.pay.notifyUrl}")
  private String notifyUrl;

  @Bean
  public WxPayService wxPayService() {
    WxPayConfig payConfig = new WxPayConfig();
    payConfig.setAppId(appId);
    payConfig.setMchId(mchId);
    payConfig.setMchKey(mchKey);
    payConfig.setNotifyUrl(notifyUrl);

    WxPayService wxPayService = new WxPayServiceImpl();
    wxPayService.setConfig(payConfig);
    return wxPayService;
  }
}