springmvc接入微信平台

1、申请微信公众号，并成为开发者，完善头像和简介。
2、在页面左侧“开发”下点击“基本配置”：

3、出现如下页面

需要填写四处：
url：即后台代码中接收并处理微信传入四个参数（signature、timestamp、nonce、echostr）对应的url。
Token：后台用于和timestamp、nonce按字典排序的字符串名称。
密钥：随机生成即可。
消息加解密方式：安全模式。

4、编写服务端java代码，这里使用springmvc。首先，web.xml的配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>notebook</display-name>
  <!-- 配置springmvc的分发器 -->
  <servlet>
    <servlet-name>notebook</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>notebook</servlet-name>
    <!-- 只拦截.do结尾的请求，所以静态资源解析器可以不配置 -->
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>
</web-app>

接着，springmvc配置文件notebook.xml：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd">

    <context:component-scan base-package="service"></context:component-scan>
    <context:component-scan base-package="login.controller"></context:component-scan>
    <mvc:annotation-driven />
     <!-- 配置视图解析器 -->
    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
       <property name="prefix" value="/WEB-INF/views/"/>
       <property name="suffix" value=".jsp"/>
    </bean>
    <!-- 配置文上传管理器 -->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
       <property name="defaultEncoding" value="UTF-8"></property>
       <property name="maxUploadSize" value="10240000"></property>   
    </bean>

    <!-- 配置静态文件解析器 -->
    <mvc:resources location="/" mapping="/**"/>
</beans>

然后，编写控制器

package login.controller;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import service.Service;
import service.ServiceImf;

@Controller
@RequestMapping(value="/login")
public class Login {

    private Service service;
    @Autowired
    public void setService(ServiceImf service){
        this.service = service;
    }


    /**
     * 微信平台接入
     */
    @RequestMapping(value="loginByWechat.do",method=RequestMethod.GET)
    public void loginByWechat(HttpServletRequest request,HttpServletResponse 
                                response){
        //获取微信后台传入的四个参数
        String signature = request.getParameter("signature");
        String timestamp = request.getParameter("timestamp");
        String nonce = request.getParameter("nonce");
        String echostr = request.getParameter("echostr");
        boolean flag = service.checkSignature(signature, timestamp, nonce);
        System.out.println(flag);
        PrintWriter p = null;
        try {
            p = response.getWriter();
            if(flag){
                p.print(echostr);//注意此处必须返回echostr以完成验证
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Service代码：

package service;

import java.util.Arrays;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import entity.User;

@Component
public class ServiceImf implements Service{

    private UtilService shalUtil;
    @Autowired
    public void setShalUtil(UtilService shalUtil){
        this.shalUtil = shalUtil;
    }

    //微信公众平台登录的签名校验
    private static final String token="wechatofjaybill";
    @Override
    public boolean checkSignature(String signature,String timestamp,String nonce) {
        //1、排序
        String [] arr = new String[]{token,timestamp,nonce};
        Arrays.sort(arr);
        //2、生成新的字符串
        StringBuffer content = new StringBuffer();
        for(int i=0;i<arr.length;i++){
            content.append(arr[i]);
        }
        //3、shal加密
        String temp = shalUtil.getSha1(content.toString());
        return temp.equals(signature);
    }


}

package service;

import java.security.MessageDigest;

import org.springframework.stereotype.Component;

@Component
public class UtilService {
    //shal加密算法
        public String getSha1(String str){
            if (null == str || 0 == str.length())
                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) {
                e.printStackTrace();
                return null;
            }
        }

}

5、最后，在第3点那个页面提交，即可完成验证。