app实现微信支付的代码

微信支付的代码需要结合具体的开发语言和框架来实现。以下是一个基于Java语言和Spring框架的微信支付示例代码：

1. 创建一个微信支付配置类，例如WechatPayConfig.java，其中包含了微信支付的相关配置：

@Configuration
public class WechatPayConfig {
    // 应用ID
    @Value("${wechat.pay.app-id}")
    private String appId;
    // 商户号
    @Value("${wechat.pay.mch-id}")
    private String mchId;
    // API密钥
    @Value("${wechat.pay.api-key}")
    private String apiKey;
    // 回调地址
    @Value("${wechat.pay.notify-url}")
    private String notifyUrl;

    // 将配置类中的属性注入到WechatPayService中
    @Bean
    public WechatPayService wechatPayService() {
        return new WechatPayServiceImpl(appId, mchId, apiKey, notifyUrl);
    }
}

2. 创建一个微信支付服务类，例如WechatPayService.java，其中包含了微信支付的相关接口：

public interface WechatPayService {
    // 统一下单接口
    Map<String, String> unifiedOrder(String outTradeNo, String body, int totalFee, String spbillCreateIp) throws Exception;

    // 查询订单接口
    Map<String, String> orderQuery(String outTradeNo) throws Exception;

    // 关闭订单接口
    Map<String, String> closeOrder(String outTradeNo) throws Exception;

    // 申请退款接口
    Map<String, String> refund(String outTradeNo, String outRefundNo, int totalFee, int refundFee) throws Exception;

    // 查询退款接口
    Map<String, String> refundQuery(String outTradeNo) throws Exception;
}

3. 创建一个微信支付服务的实现类，例如WechatPayServiceImpl.java，其中实现了微信支付服务的相关接口。这里使用了官方提供的Java SDK：

@Service
public class WechatPayServiceImpl implements WechatPayService {
    private final WxPayService wxPayService;

    public WechatPayServiceImpl(String appId, String mchId, String apiKey, String notifyUrl) {
        WxPayConfig payConfig = new WxPayConfig();
        payConfig.setAppId(appId);
        payConfig.setMchId(mchId);
        payConfig.setMchKey(apiKey);
        payConfig.setNotifyUrl(notifyUrl);

        this.wxPayService = new WxPayServiceImpl();
        this.wxPayService.setConfig(payConfig);
    }

    @Override
    public Map<String, String> unifiedOrder(String outTradeNo, String body, int totalFee, String spbillCreateIp) throws Exception {
        WxPayUnifiedOrderRequest request = new WxPayUnifiedOrderRequest();
        request.setOutTradeNo(outTradeNo);
        request.setBody(body);
        request.setTotalFee(totalFee);
        request.setSpbillCreateIp(spbillCreateIp);
        request.setTradeType(WxPayConstants.TradeType.APP);

        WxPayUnifiedOrderResult result = wxPayService.unifiedOrder(request);
        return result.toMap();
    }

    @Override
    public Map<String, String> orderQuery(String outTradeNo) throws Exception {
        WxPayOrderQueryRequest request = new WxPayOrderQueryRequest();
        request.setOutTradeNo(outTradeNo);

        WxPayOrderQueryResult result = wxPayService.queryOrder(request);
        return result.toMap();
    }

    @Override
    public Map<String, String> closeOrder(String outTradeNo) throws Exception {
        WxPayOrderCloseRequest request = new WxPayOrderCloseRequest();
        request.setOutTradeNo(outTradeNo);

        WxPayOrderCloseResult result = wxPayService.closeOrder(request);
        return result.toMap();
    }

    @Override
    public Map<String, String> refund(String outTradeNo, String outRefundNo, int totalFee, int refundFee) throws Exception {
        WxPayRefundRequest request = new WxPayRefundRequest();
        request.setOutTradeNo(outTradeNo);
        request.setOutRefundNo(outRefundNo);
        request.setTotalFee(totalFee);
        request.setRefundFee(refundFee);

        WxPayRefundResult result = wxPayService.refund(request);
        return result.toMap();
    }

    @Override
    public Map<String, String> refundQuery(String outTradeNo) throws Exception {
        WxPayRefundQueryRequest request = new WxPayRefundQueryRequest();
        request.setOutTradeNo(outTradeNo);

        WxPayRefundQueryResult result = wxPayService.refundQuery(request);
        return result.toMap();
    }
}

4. 在需要使用微信支付的地方，注入WechatPayService，调用相关接口即可。

以上仅是一个示例代码，具体实现需要根据实际情况进行调整和完善。