1.引入依赖

<dependency><groupId>com.github.wechatpay-apiv3</groupId><artifactId>wechatpay-java</artifactId><version>0.2.10</version>
</dependency>

2.创建预支付订单

import com.wechat.pay.java.core.Config;
import com.wechat.pay.java.core.RSAConfig;
import com.wechat.pay.java.service.payments.jsapi.JsapiService;
import com.wechat.pay.java.service.payments.jsapi.model.Amount;
import com.wechat.pay.java.service.payments.jsapi.model.Payer;
import com.wechat.pay.java.service.payments.jsapi.model.PrepayRequest;
import com.wechat.pay.java.service.payments.jsapi.model.PrepayResponse;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;@Component
public class WeiXinPay {//@Value("${weixin.appId}")private String weixinAppId;/** 商户号 */public static String merchantId = "";/** 商户API私钥路径 */public static String privateKeyPath = "";/** 商户证书序列号 例如-证书序列号：54776TTTF8F77EXXX3641FAB5F940FII11C65347*/public static String merchantSerialNumber = "";/** 微信支付平台证书路径 例如：wechatpay_3A4AF69999DF01F39BB08C21C1C29B6AA17C074N.pem*/public static String wechatPayCertificatePath = "";/** 微信支付 APIv3 密钥 */public static String apiV3Key = "";public String createPreparePay() {Config config =new RSAConfig.Builder()//商户ID.merchantId(merchantId)//商户私钥文件(apiclient_key.pem)路径.privateKeyFromPath(privateKeyPath)//商户证书序列号 例如-证书序列号：54776TTTF8F77EXXX3641FAB5F940FII11C65347.merchantSerialNumber(merchantSerialNumber)//微信支付平台证书文件路径 例如：wechatpay_3A4AF69999DF01F39BB08C21C1C29B6AA17C074N.pem.wechatPayCertificatesFromPath(wechatPayCertificatePath).build();JsapiService service = new JsapiService.Builder().config(config).build();PrepayRequest request = new PrepayRequest();Amount amount = new Amount();amount.setTotal(100);request.setAmount(amount);request.setAppid("wxa9d9651ae******");request.setMchid("190000****");request.setDescription("测试商品标题");request.setNotifyUrl("https://notify_url");request.setOutTradeNo("out_trade_no_001");Payer payer = new Payer();payer.setOpenid("oLTPCuN5a-nBD4rAL_fa********");request.setPayer(payer);PrepayResponse response = service.prepay(request);System.out.println(response.getPrepayId());return "";}
}