[Java知识库]微信支付 发起商家转账API 2022年v3 transfer batches

1 概述

微信转账新接口 发起商家转账API 微信开发文档

接口说明
适用对象：直连商户
请求URL：https://api.mch.weixin.qq.com/v3/transfer/batches
请求方式：POST
接口限频： 单个商户 50QPS，如果超过频率限制，会报错FREQUENCY_LIMITED，请降低频率请求。
是否需要证书：是

商户可以通过该接口同时向多个用户微信零钱进行转账操作。

2 发起微信转账 请求参数组装

import cn.hutool.core.util.IdUtil;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import lombok.extern.slf4j.Slf4j;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Slf4j
public class WechatPay {
	private static final Gson GSON = new GsonBuilder().create();

	public static void main(String[] args) throws Exception {
	   //测试微信转账
		weixinTransferBat();
	}
	//请看下面
    public static String weixinTransferBat() {...};

	public static String weixinTransferBat() throws Exception {


		//商户号
		String mchid = "";
		//申请商户号的appid或商户号绑定的appid（企业号corpid即为此appid）
		String appId = "";
		//用户在直连商户应用下的用户标示
		String openId = "";
		//商户证书编号
		String wechatPayserialNo = "";
		//商户证书路径（在你本机测试时放你本机路径中的就可以）
		String privatekeypath = "";


		Map<String, Object> postMap = new HashMap<String, Object>();

		//商家批次单号 长度 1~32
		String outNo = IdUtil.getSnowflake(0, 0).nextIdStr();

		postMap.put("appid", appId);
		postMap.put("out_batch_no", outNo);
		//该笔批量转账的名称
		postMap.put("batch_name", "测试转账");
		//转账说明，UTF8编码，最多允许32个字符
		postMap.put("batch_remark", "测试转账");
		//转账金额单位为“分”。 总金额
		postMap.put("total_amount", 100);
		//。转账总笔数
		postMap.put("total_num", 1);


		List<Map> list = new ArrayList<>();
		Map<String, Object> subMap = new HashMap<>(4);
		//商家明细单号
		subMap.put("out_detail_no", outNo);
		//转账金额
		subMap.put("transfer_amount", 100);
		//转账备注
		subMap.put("transfer_remark", "明细备注1");
		//用户在直连商户应用下的用户标示
		subMap.put("openid", openId);
//		subMap.put("user_name", RsaCryptoUtil.encryptOAEP(userName, x509Certificate));
		list.add(subMap);
		postMap.put("transfer_detail_list", list);

        //发起转账操作
		String resStr = HttpUtil.postTransBatRequest(
				"https://api.mch.weixin.qq.com/v3/transfer/batches",
				GSON.toJson(postMap),
				wechatPayserialNo,
				mchid,
				privatekeypath);
}

商家批次单号，因为我这里只有一笔，所以用了同一个，读者可以生成多个批次单号, IdUtil 我用的是 cn.hutool 中的工具类，依赖如下：

<!-- https://mvnrepository.com/artifact/cn.hutool/hutool-all -->
<dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-all</artifactId>
    <version>5.8.2</version>
</dependency>

证书序列号需要在微信商户后台申请

3 发起微信转账 请求核心代码

import lombok.extern.slf4j.Slf4j;
import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;

import org.apache.http.util.EntityUtils;


/**
 * 微信支付专用类 请求操作方法
 *
 * @author Administrator
 */
@Slf4j
public class HttpUtil {
	/**
	 * 发起批量转账API 批量转账到零钱
	 *
	 * @param requestUrl
	 * @param requestJson 组合参数
	 * @param wechatPayserialNo 商户证书序列号
	 * @param mchID4M  商户号 
	 * @param privatekeypath  商户私钥证书路径
	 * @return
	 */
	public static String postTransBatRequest(
			String requestUrl,
			String requestJson,
			String wechatPayserialNo,
			String mchID4M,
			String privatekeypath) {
		CloseableHttpClient httpclient = HttpClients.createDefault();
		CloseableHttpResponse response = null;
		HttpEntity entity = null;
		try {
			//商户私钥证书
			HttpPost httpPost = new HttpPost(requestUrl);
			// NOTE: 建议指定charset=utf-8。低于4.4.6版本的HttpCore，不能正确的设置字符集，可能导致签名错误
			httpPost.addHeader("Content-Type", "application/json");
			httpPost.addHeader("Accept", "application/json");
			//"55E551E614BAA5A3EA38AE03849A76D8C7DA735A");
			httpPost.addHeader("Wechatpay-Serial", wechatPayserialNo);
			//-------------------------核心认证 start-----------------------------------------------------------------
			String strToken = VechatPayV3Util.getToken("POST",
					"/v3/transfer/batches",
					requestJson,mchID4M,wechatPayserialNo, privatekeypath);
			
			log.error("微信转账token "+strToken);
			// 添加认证信息
			httpPost.addHeader("Authorization",
					"WECHATPAY2-SHA256-RSA2048" + " "
							+ strToken);
			//---------------------------核心认证 end---------------------------------------------------------------
			httpPost.setEntity(new StringEntity(requestJson, "UTF-8"));
			//发起转账请求
			response = httpclient.execute(httpPost);
			entity = response.getEntity();//获取返回的数据
			log.info("-----getHeaders.Request-ID:"+response.getHeaders("Request-ID"));
			return EntityUtils.toString(entity);
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			// 关闭流
		}
		return null;
	}

}

3.1 微信转账 token

微信转账 token 签名认证 这套是固定的，大家可以直接复制使用

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.Signature;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.Random;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.codec.binary.Base64;

import org.springframework.util.StringUtils;

@Slf4j
public class VechatPayV3Util {

	/**
	 * 
	 * @param method 请求方法 post
	 * @param canonicalUrl 请求地址
	 * @param body 请求参数
	 * @param merchantId 这里用的商户号
	 * @param certSerialNo 商户证书序列号
	 * @param keyPath 商户证书地址
	 * @return
	 * @throws Exception
	 */
	public static String getToken(
			String method,
			String canonicalUrl,
			String body,
			String merchantId,
			String certSerialNo,
			String keyPath) throws Exception {
		String signStr = "";
		//获取32位随机字符串
        String nonceStr = getRandomString(32);
		//当前系统运行时间
		long timestamp = System.currentTimeMillis() / 1000;
		if (StringUtils.isEmpty(body)) {
			body = "";
		}
		//签名操作
		String message = buildMessage(method, canonicalUrl, timestamp, nonceStr, body);
		//签名操作
		String signature = sign(message.getBytes("utf-8"), keyPath);
		//组装参数
		signStr = "mchid=\"" + merchantId + "\",timestamp=\"" +  timestamp+ "\",nonce_str=\"" + nonceStr
				+ "\",serial_no=\"" + certSerialNo + "\",signature=\"" + signature + "\"";
		
		return signStr;
	}

	public static String buildMessage(String method, String canonicalUrl, long timestamp, String nonceStr, String body) {
//		String canonicalUrl = url.encodedPath();
//		if (url.encodedQuery() != null) {
//			canonicalUrl += "?" + url.encodedQuery();
//		}
		return method + "\n" + canonicalUrl + "\n" + timestamp + "\n" + nonceStr + "\n" + body + "\n";
	}

	public static String sign(byte[] message, String keyPath) throws Exception {
		Signature sign = Signature.getInstance("SHA256withRSA");
		sign.initSign(getPrivateKey(keyPath));
		sign.update(message);
		return Base64.encodeBase64String(sign.sign());
	}

	/**
	   * 微信支付-前端唤起支付参数-获取商户私钥
	   *
	   * @param filename 私钥文件路径  (required)
	   * @return 私钥对象
	   */
	  public static PrivateKey getPrivateKey(String filename) throws IOException {

	  	log.error("签名 证书地址是 "+filename);
	      String content = new String(Files.readAllBytes(Paths.get(filename)), "utf-8");
	      try {
	          String privateKey = content.replace("-----BEGIN PRIVATE KEY-----", "")
	                  .replace("-----END PRIVATE KEY-----", "")
	                  .replaceAll("\\s+", "");
	          //System.out.println("--------privateKey---------:"+privateKey);
	          KeyFactory kf = KeyFactory.getInstance("RSA");
	          return kf.generatePrivate(
	                  new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKey)));
	      } catch (NoSuchAlgorithmException e) {
	          throw new RuntimeException("当前Java环境不支持RSA", e);
	      } catch (InvalidKeySpecException e) {
	          throw new RuntimeException("无效的密钥格式");
	      }
	  }
	/**
	 * 获取随机位数的字符串
	 * @param length
	 * @return
	 */
	public static String getRandomString(int length) {
		String base = "abcdefghijklmnopqrstuvwxyz0123456789";
		Random random = new Random();
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < length; i++) {
			int number = random.nextInt(base.length());
			sb.append(base.charAt(number));
		}
		return sb.toString();
	}
}

4 处理微信转账结果

如果正常微信转账成功，则会返回 JSON 格式的单号等信息

{
  "out_batch_no": "plfk2020042013",
  "batch_id": "1030000071100999991182020050700019480001",
  "create_time": "2015-05-20T13:29:35.120+08:00"
}

小编这里定义的java bean 解析

//GSON 文章开头有声明
//resStr 微信转账请求结果 发起转账操作结果
TransferResponsEntity transferResponsEntity = GSON.fromJson(resStr, TransferResponsEntity.class);

TransferResponsEntity 的定义如下：

@Data
@NoArgsConstructor
public class TransferResponsEntity implements Serializable {

	private String code;
	private String message;
	private String batch_id;
	private String out_batch_no;

	@Override
	public String toString() {
		return "TransferResponsEntity{" +
				"code='" + code + '\'' +
				", message='" + message + '\'' +
				", batch_id='" + batch_id + '\'' +
				", out_batch_no='" + out_batch_no + '\'' +
				'}';
	}
}

转账成功的时候 code 值为null ，转账失败里，code 、message 值不为 null.

如果提示你全额不足，可能是运营商账户问题

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