Java+微信公众号开发过程步骤详解

import java.security.MessageDigest;
import java.util.Arrays;

public class CheckUtil {
	public static final String  tooken = "自行定义"; //开发者自行定义Tooken
	public static boolean checkSignature(String signature,String timestamp,String nonce){
		//1.定义数组存放tooken，timestamp,nonce
		String[] arr = {tooken,timestamp,nonce};
		//2.对数组进行排序
		Arrays.sort(arr);
		//3.生成字符串
		StringBuffer sb = new StringBuffer();
		for(String s : arr){
			sb.append(s);
		}
		//4.sha1加密,网上均有现成代码
		String temp = getSha1(sb.toString());
		//5.将加密后的字符串，与微信传来的加密签名比较，返回结果
		return temp.equals(signature);
	}

	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) {
            // TODO: handle exception
            return null;
        }
    }
}

public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		response.setContentType("text/html");
		String signature = request.getParameter("signature");
		String timestamp = request.getParameter("timestamp");
		String nonce = request.getParameter("nonce");
		String echostr = request.getParameter("echostr");
		PrintWriter out = response.getWriter();
		if(CheckUtil.checkSignature(signature, timestamp, nonce)){
			//如果校验成功，将得到的随机字符串原路返回
			out.print(echostr);
		}
	}