package com.weixin.test;

import java.security.MessageDigest;

/**
 * 微信测试MD5
 * @author Administrator
 *
 */
public class MD5Util {

    private static String byteArrayToHexString(byte b[]) {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++)
            resultSb.append(byteToHexString(b[i]));

        return resultSb.toString();
    }

    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0)
            n += 256;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    public static String MD5Encode(String origin, String charsetname) {
        String resultString = null;
        try {
            resultString = new String(origin);
            MessageDigest md = MessageDigest.getInstance("MD5");
            if (charsetname == null || "".equals(charsetname))
                resultString = byteArrayToHexString(md.digest(resultString.getBytes()));
            else
                resultString = byteArrayToHexString(md.digest(resultString.getBytes(charsetname)));
        } catch (Exception exception) {
        }
        return resultString;
    }

    private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

}

package com.weixin.test;

import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;

public class PayTest {

    // http://mch.weixin.qq.com/wiki/doc/api/index.php?chapter=4_3
    private static String Key = "192006250b4c09247ec02edce69f6a2d";

    /**
     * @param args
     */
    public static void main(String[] args) {
        System.out.println(">>>模拟微信支付<<<");
        System.out.println("==========华丽的分隔符==========");
        // 微信api提供的参数
        String appid = "wxd930ea5d5a258f4f";
        String mch_id = "10000100";
        String device_info = "1000";
        String body = "test";
        String nonce_str = "ibuaiVcKdpRxkhJA";

        SortedMap<Object, Object> parameters = new TreeMap<Object, Object>();
        parameters.put("appid", appid);
        parameters.put("mch_id", mch_id);
        parameters.put("device_info", device_info);
        parameters.put("body", body);
        parameters.put("nonce_str", nonce_str);

        String characterEncoding = "UTF-8";
        String weixinApiSign = "9A0A8659F005D6984697E2CA0A9CF3B7";
        System.out.println("微信的签名是：" + weixinApiSign);
        String mySign = createSign(characterEncoding, parameters);
        System.out.println("我     的签名是：" + mySign);

        if (weixinApiSign.equals(mySign)) {
            System.out.println("恭喜你成功了~");
        } else {
            System.out.println("不行啊，再接再厉~");
        }

        String userAgent = "Mozilla/5.0(iphone;CPU iphone OS 5_1_1 like Mac OS X) AppleWebKit/534.46(KHTML,like Geocko) Mobile/9B206 MicroMessenger/5.0";

        char agent = userAgent.charAt(userAgent.indexOf("MicroMessenger") + 15);

        System.out.println("微信的版本号：" + new String(new char[] { agent }));
    }

    /**
     * 微信支付签名算法sign
     * @param characterEncoding
     * @param parameters
     * @return
     */
    @SuppressWarnings("unchecked")
    public static String createSign(String characterEncoding, SortedMap<Object, Object> parameters) {
        StringBuffer sb = new StringBuffer();
        Set es = parameters.entrySet();// 所有参与传参的参数按照accsii排序（升序）
        Iterator it = es.iterator();
        while (it.hasNext()) {
            Map.Entry entry = (Map.Entry) it.next();
            String k = (String) entry.getKey();
            Object v = entry.getValue();
            if (null != v && !"".equals(v) && !"sign".equals(k) && !"key".equals(k)) {
                sb.append(k + "=" + v + "&");
            }
        }
        sb.append("key=" + Key);
        String sign = MD5Util.MD5Encode(sb.toString(), characterEncoding).toUpperCase();
        return sign;
    }

}