小程序获取登录code和用户加密信息方法

      wx.login({
        success(res) {
          console.log("postLogin login success", res);
          if (!res.code) {
            reject();
          }
          wx.getUserInfo({
            withCredentials: true,
            success(userRes) {
              app.api.user.postLogin({
                'code': res.code,
                "signature":userRes.signature,
                "rawData":userRes.rawData,
                'encryptedData': userRes.encryptedData,
                'iv': userRes.iv
              }).onSuccess(function (res) {
                if (res) {
                  resolve(res);
                } else {
                  reject();
                  util.showErrorMessage("登录失败");
                }
              }).onFail(function (res) {
                reject();
                util.showErrorMessage(res.msg);
              }).start();
            }
          })
        }
      });

小程序传参对象类WxLoginVO，代码注释已经说明相关参数，这里就不做解释

package com.frank.lmsg.vo.req;

import java.io.Serializable;

/**
 *
 * Description: 用户信息 微信登录验证VO
 * Auth: Frank
 * Date: 2019-08-09
 * Time: 下午 2:22
 */
public class WxLoginVO implements Serializable {
    /**
     * 对应小程序获取用户信息的encryptedData字段
     */
    private String encryptedData;

    /**
     * 对应小程序获取用户信息的iv字段
     */
    private String iv;

    /**
     * 对应小程序获取用户信息的rawData字段
     */
    private String rawData;

    /**
     * 对应小程序获取用户信息的signature字段
     */
    private String signature;

    /**
     * 对应小程序登录的时候反的code字段
     */
    private String code;

    public String getEncryptedData() {
        return encryptedData;
    }

    public void setEncryptedData(String encryptedData) {
        this.encryptedData = encryptedData;
    }

    public String getIv() {
        return iv;
    }

    public void setIv(String iv) {
        this.iv = iv;
    }

    public String getRawData() {
        return rawData;
    }

    public void setRawData(String rawData) {
        this.rawData = rawData;
    }

    public String getSignature() {
        return signature;
    }

    public void setSignature(String signature) {
        this.signature = signature;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    @Override
    public String toString() {
        return "WxLoginVO{" +
                "encryptedData='" + encryptedData + '\'' +
                ", iv='" + iv + '\'' +
                ", rawData='" + rawData + '\'' +
                ", signature='" + signature + '\'' +
                ", code='" + code + '\'' +
                '}';
    }
}

微信相关工具类WxUtils，代码注释已经说明相关方法，这里就不做解释

package com.frank.lmsg.base.utils;

import com.alibaba.fastjson.JSONObject;
import com.frank.lmsg.constant.WxConsts;
import com.frank.lmsg.vo.resp.UserInfoVo;
import com.frank.lmsg.vo.resp.WxUserInfoVO;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.logging.log4j.LogManager;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.AlgorithmParameters;
import java.security.Security;
import java.text.MessageFormat;
import java.util.Arrays;
import java.util.Base64;

/**
 * 微信用户信息解密工具
 *
 * @author Giam
 * @version 1.0
 * @date 2019/6/19
 */
public class WxUtils {
    /**
     * 微信获取用户信息 encryptedData解密
     * <p>
     *     解密算法如下：
     *     1.对称解密使用的算法为 AES-128-CBC，数据采用PKCS#7填充。
     *     2. 对称解密的目标密文为 Base64_Decode(encryptedData)。
     *     3. 对称解密秘钥 aeskey = Base64_Decode(session_key), aeskey 是16字节。
     *     4. 对称解密算法初始向量 为Base64_Decode(iv)，其中iv由数据接口返回。
     * </p>
     *
     * @param encryptedData 加密的数据
     * @param sessionKey sessionKey
     * @param iv iv
     * @return
     */
    public static WxUserInfoVO encryptedDataUserInfo(String encryptedData, String sessionKey, String iv){
        // 被加密的数据
        Base64.Decoder decoder = Base64.getDecoder();

        byte[] dataByte = decoder.decode(encryptedData);
        // 加密秘钥
        byte[] keyByte = decoder.decode(sessionKey);
        // 偏移量
        byte[] ivByte = decoder.decode(iv);

        try {
            // 如果密钥不足16位，那么就补足.  这个if 中的内容很重要
            int base = 16;
            if (keyByte.length % base != 0) {
                int groups = keyByte.length / base + (keyByte.length % base != 0 ? 1 : 0);
                byte[] temp = new byte[groups * base];
                Arrays.fill(temp, (byte) 0);
                System.arraycopy(keyByte, 0, temp, 0, keyByte.length);
                keyByte = temp;
            }
            // 初始化
            Security.addProvider(new BouncyCastleProvider());
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding","BC");
            SecretKeySpec spec = new SecretKeySpec(keyByte, "AES");
            AlgorithmParameters parameters = AlgorithmParameters.getInstance("AES");
            parameters.init(new IvParameterSpec(ivByte));
            cipher.init(Cipher.DECRYPT_MODE, spec, parameters);
            byte[] resultByte = cipher.doFinal(dataByte);
            if (null != resultByte && resultByte.length > 0) {
                String result = new String(resultByte, StandardCharsets.UTF_8);
                return JSONObject.parseObject(result, WxUserInfoVO.class);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     *  获得微信signature
     *  signature = sha1( rawData + session_key )
     * @param rawData rawData
     * @param sessionKey sessionKey
     * @return
     */
    public static String getSignature(String rawData, String sessionKey) {
        StringBuffer signatureStr = new StringBuffer();
        signatureStr.append(rawData);
        signatureStr.append(sessionKey);
        return DigestUtils.sha1Hex(signatureStr.toString().getBytes());
    }

    /**
     * 获取登录信息URL并拼接相关参数
     * @param api
     * @param arg
     * @return
     */
    public static String getApi(String api, Object... arg) {
        String url = String.format(api, WxConsts.APP_ID, WxConsts.APP_SECRET);
        url = MessageFormat.format(url, arg);
        return url;
    }


}

登录微信请求工具类HttpUtils，代码注释已经说明相关方法，这里就不做解释

package com.frank.lmsg.base.utils;

import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.net.URI;
import java.util.Map;

public class HttpUtils {
    public static String doGet(String url, Map<String, String> param) {

        // 创建Httpclient对象
        CloseableHttpClient httpclient = HttpClients.createDefault();

        String resultString = "";
        CloseableHttpResponse response = null;
        try {
            // 创建uri
            URIBuilder builder = new URIBuilder(url);
            if (param != null) {
                for (String key : param.keySet()) {
                    builder.addParameter(key, param.get(key));
                }
            }
            URI uri = builder.build();

            // 创建http GET请求
            HttpGet httpGet = new HttpGet(uri);

            // 执行请求
            response = httpclient.execute(httpGet);
            // 判断返回状态是否为200
            if (response.getStatusLine().getStatusCode() == 200) {
                resultString = EntityUtils.toString(response.getEntity(), "UTF-8");
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (response != null) {
                    response.close();
                }
                httpclient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return resultString;
    }

    public static String doGet(String url) {
        return doGet(url, null);
    }
}

详细代码可以查看：
https://github.com/fuxingkai/LMsg
https://github.com/fuxingkai/LMsg-B
参考地址：
https://developers.weixin.qq.com/miniprogram/dev/api/open-api/login/wx.login.html
https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/login/auth.code2Session.html
https://developers.weixin.qq.com/miniprogram/dev/api/open-api/user-info/wx.getUserInfo.html
https://developers.weixin.qq.com/miniprogram/dev/framework/open-ability/signature.html