如何使用Java开发微信公众号

package com.blog.springboot.controller;

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

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

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.blog.springboot.wx.service.WxService;
import com.blog.springboot.wx.util.SignUtil;

import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;

@RestController
@RequestMapping("/wx_public_api")
@Api(tags = { "微信公众号api" }, description = "微信公众号api")
public class WxPublicApiController extends AbstractController{

	@Autowired
	private WxService wxService;
	
	
       /**
        * 微信公众平台服务器配置验证
        * @param request
        * @param response
        */
	   @GetMapping
	   @ApiOperation("微信公众平台服务器配置验证")
	   public void validate(HttpServletRequest request, HttpServletResponse response) {
	        // 微信加密签名，signature结合了开发者填写的token参数和请求中的timestamp参数、nonce参数。
	        String signature = request.getParameter("signature");
	        // 时间戳
	        String timestamp = request.getParameter("timestamp");
	        // 随机数
	        String nonce = request.getParameter("nonce");
	        // 随机字符串
	        String echostr = request.getParameter("echostr");

	        PrintWriter out = null;
	        try {
	            out = response.getWriter();
	            // 通过检验signature对请求进行校验，若校验成功则原样返回echostr，否则接入失败
	            if (SignUtil.checkSignature(signature, timestamp, nonce)) {
	                out.print(echostr);
	            }
	        } catch (IOException e) {
	            e.printStackTrace();
	            logger.error(e.getMessage());
	            
	        } finally {
	            
	        	out.close();
	            out = null;
	        }
	    }

     /**
      * 关注推送消息
      * @param request
      * @param response
      */
	 @PostMapping
	 @ApiOperation("关注推送消息")
	 public void about(HttpServletRequest request, HttpServletResponse response) {
	        try {
	            request.setCharacterEncoding("UTF-8");
	        } catch (UnsupportedEncodingException e) {
	            e.printStackTrace();
	            logger.error(e.getMessage(),e);
	        }
	        response.setContentType("text/html;charset=UTF-8");

	        // 调用核心业务类接收消息、处理消息
	        String respMessage = wxService.newMessageRequest(request);

	        // 响应消息
	        PrintWriter out = null;
	        try {
	            out = response.getWriter();
	            out.print(respMessage);
	        } catch (IOException e) {
	            e.printStackTrace();
	            logger.error(e.getMessage(),e);
	        } finally {
	            out.close();
	            out = null;
	        }
	    }
}