微信小程序卡券领取

首先在公众号后台获取卡券id，获取公众号的appid和accessToken，opendid（小程序端）：小程序登陆时获取存起来

导入weixin4j包

java代码，小程序略

package com.enation.app.shop.wechat.controller;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.weixin4j.WeixinException;
import org.weixin4j.http.HttpsClient;
import org.weixin4j.http.Response;

import com.enation.app.shop.wechat.model.AccessToken;
import com.enation.app.shop.wechat.model.ApiTicket;
import com.enation.app.shop.wechat.model.WeixinSignature;
import com.enation.app.shop.wechat.utils.WeChatCart;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;


@Controller
@RequestMapping("/")
public class WechatGetTicket {
    public static ApiTicket ticket = null;//使用全局静态变量存储ApiTicket对象，当然如果使用缓存框架保存当然更好，这边只是做一个简单示例
    private final static String string = "0123456789";
    final private static char[] chars = string.toCharArray();
/**
 * @Description: 获取领取卡券获取签名等参数
 * @param cardId：需要领取的卡券的cardId
 * @return
 * @throws WeixinException
 * @throws JsonParseException
 * @throws JsonMappingException
 * @throws IOException
 */
@RequestMapping("/")
@ResponseBody
public Map getCardSign(String cardId) throws WeixinException, JsonParseException, JsonMappingException, IOException{
	Map ret = new HashMap();
	//先要获取api_ticket，由于请求api_ticket的接口访问有次数限制，所以最好将获得到的api_ticket保存到缓存中，这边做法比较简单，直接使用的静态变量
	if(ticket == null || ticket.getExpires_in() < System.currentTimeMillis()){
		//创建请求对象
        	HttpsClient http = new HttpsClient();
        
        	ObjectMapper mapper = new ObjectMapper();
        
        	AccessToken token = WeChatCart.getToken();//这里获取的token就是最上方代码保存的微信公众号全局静态变量token
   	 		
        	System.out.println(token.getErrcode());
        	
   	 		//通过access_token调用获取api_ticket接口
    		Response res = http.get("https://api.weixin.qq.com/cgi-bin/ticket/getticket?access_token=" + token.getAccess_token() + "&type=wx_card");
    		System.out.println("api_ticket:===========>"+res.asString());
    		ticket = mapper.readValue(res.asString(), ApiTicket.class);
   		}
   
   		ret = sign(ticket.getTicket(), cardId);//生成领取卡券需要的签名，并返回相关的参数

   		for (Map.Entry entry : ret.entrySet()) {
       		System.out.println(entry.getKey() + ", " + entry.getValue());
   		}
   		return ret;
}
/**
 * @param api_ticket：
 * @param cardId：需要领取的卡券的cardId
 * @return
 * @Description: 生成卡券需要的签名并返回参数
 */
public static Map sign(String api_ticket, String cardId) {
    Map ret = new HashMap();
    String nonce_str = create_nonce_str();
    String timestamp = create_timestamp();
    String signature = "";
    
    WeixinSignature signatures = new WeixinSignature(api_ticket, timestamp, cardId, nonce_str);
    ret.put("card_id", cardId);
    ret.put("api_ticket", api_ticket);
    ret.put("nonceStr", nonce_str);
    ret.put("timestamp", timestamp);
    ret.put("signature", signatures.sign());
    return ret;
}

	/**
	 * 返回时间戳（秒）
	 * @return
	 */
	private static String create_timestamp() {
	    return String.valueOf(new Date().getTime() / 1000);
	}
	
	/**
	 * 返回随机字符串
	 * @return
	 */
	private static String create_nonce_str() {
		
	    String nonce = new String();
	    for (int i = 0; i < 32; i++) {
	        int rannum = (int) (Math.random() * 1000) % (chars.length);
	        nonce += chars[rannum];
	    }
	    return nonce;
	}
	/**
     * Convert byte[] to hex string
     * @param src byte[] data
     * @return hex string
     */
    public static String bytesToHexString(byte[] src) {
        StringBuilder stringBuilder = new StringBuilder("");
        if (src == null || src.length <= 0) {
            return null;
        }
        for (int i = 0; i < src.length; i++) {
            int v = src[i] & 0xFF;
            String hv = Integer.toHexString(v);
            if (hv.length() < 2) {
                stringBuilder.append(0);
            }
            stringBuilder.append(hv);
        }
        return stringBuilder.toString();
    }
}

package com.enation.app.shop.wechat.base;

public class BaseResponse {
	private int errcode;
	private String errmsg;
	
	public int getErrcode() {
		return errcode;
	}
	public void setErrcode(int errcode) {
		this.errcode = errcode;
	}
	public String getErrmsg() {
		return errmsg;
	}
	public void setErrmsg(String errmsg) {
		this.errmsg = errmsg;
	}
}

package com.enation.app.shop.wechat.model;

import com.enation.app.shop.wechat.base.BaseResponse;

public class AccessToken extends BaseResponse{
	private String access_token;
	private long expires_in;
	
	public String getAccess_token() {
		return access_token;
	}
	public void setAccess_token(String access_token) {
		this.access_token = access_token;
	}
	public long getExpires_in() {
		return expires_in;
	}
	public void setExpires_in(long expires_in) {
		this.expires_in = System.currentTimeMillis() + (expires_in - 100) * 1000;//原expires_in是有效时长，比如：7200，现改为过期的时间戳
	}
}

package com.enation.app.shop.wechat.model;

import com.enation.app.shop.wechat.base.BaseResponse;

public class ApiTicket extends BaseResponse{
	private String ticket;
	private long expires_in;
	
	public String getTicket() {
		return ticket;
	}
	public void setTicket(String ticket) {
		this.ticket = ticket;
	}
	public long getExpires_in() {
		return expires_in;
	}
	public void setExpires_in(long expires_in) {
		this.expires_in = System.currentTimeMillis() + (expires_in - 100) * 1000;//原expires_in是有效时长，比如：7200，现改为过期的时间戳
	}
}

package com.enation.app.shop.wechat.model;

public class OAuthJsToken {
	private String openid;				//用户唯一标识
	private int expires_in = 7200;		       //凭证有效时间，单位：秒
	private String session_key;			//会话密匙
	private long exprexpiredTime;			//过期时间
	
	public String getOpenid() {
		return openid;
	}
	public void setOpenid(String openid) {
		this.openid = openid;
	}
	public int getExpires_in() {
		return expires_in;
	}
	public void setExpires_in(int expires_in) {
		this.expires_in = expires_in;
		this.exprexpiredTime = System.currentTimeMillis() + expires_in * 1000;
	}
	public String getSession_key() {
		return session_key;
	}
	public void setSession_key(String session_key) {
		this.session_key = session_key;
	}
	
	public long getExprexpiredTime() {
		return exprexpiredTime;
	}
	public void setExprexpiredTime(long exprexpiredTime) {
		this.exprexpiredTime = exprexpiredTime;
	}
	/**
     * 判断用户凭证是否过期
     *
     * @return 过期返回 true,否则返回false
     */
    public boolean isExprexpired() {
    	return System.currentTimeMillis() >= this.exprexpiredTime;
    }
}

package com.enation.app.shop.wechat.model;

import java.util.Arrays;

import com.enation.app.shop.wechat.utils.GetSha1;

public class WeixinSignature
{
  private String api_ticket;
  private String timestamp;
  private String card_id;
  private String nonce_str;

  public WeixinSignature(String api_ticket, String timestamp, String card_id, String nonce_str)
  {
    this.api_ticket = api_ticket;
    this.timestamp = timestamp;
    this.card_id = card_id;
    this.nonce_str = nonce_str;
  }

  public String sign()
  {
    String[] str = { this.api_ticket, this.timestamp, this.card_id, this.nonce_str };
    System.out.println("加密调用的加密参数" + str.toString());
    Arrays.sort(str);
    String string = new String();
    for (int i = 0; i < 4; i++) {
      string = string + str[i];
    }
    String signature = null;
    signature = GetSha1.getSha1(string);
    return signature;
  }
}

package com.enation.app.shop.wechat.utils;

import java.security.MessageDigest;

public class GetSha1
{
  public static String getSha1(String str)
  {
    if ((str == null) || (str.length() == 0)) {
      return null;
    }
    char[] hexDigits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 
      'a', 'b', 'c', 'd', 'e', 'f' };
    try {
      MessageDigest mdTemp = MessageDigest.getInstance("SHA1");
      mdTemp.update(str.getBytes("UTF-8"));

      byte[] md = mdTemp.digest();
      int j = md.length;
      char[] buf = new char[j * 2];
      int k = 0;
      for (int i = 0; i < j; i++) {
        byte byte0 = md[i];
        buf[(k++)] = hexDigits[(byte0 >>> 4 & 0xF)];
        buf[(k++)] = hexDigits[(byte0 & 0xF)];
      }
      return new String(buf);
    } catch (Exception e) {
    }
    return null;
  }
}