所需环境
1.微信开发者工具
2.eclipse
小程序端

Java后端
运行结果

注意事项

不校验合法域名在详情中，这个勾勾一定要勾上，不然就会这样

最后代码附上
w微信端wxml:

<form>
<button bindtap=\'setcontent\'>发送</button>
</form>

微信端js：

setcontent: function(){
    wx.request({
      url: \'http://localhost:8080/servletTest/test\',
      data: {

        name:"tom",


      },
      method: \'get\',
      header: {
        \'content-type\': \'application/x-www-form-urlencoded\' // 默认值
      },
      success: function (res) {
        console.log(res.data);
      },
      fail: function (res) {
        console.log("反馈未提交，请检查网络");
      }
    })
  }

java后端的servlet：

package servletTest;

import java.io.IOException;
import java.io.Writer;

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


public class servlet02 extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
  
	
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        
        response.setContentType("text/html;charset=utf-8");          
        /* 设置响应头允许ajax跨域访问 */  
        response.setHeader("Access-Control-Allow-Origin", "*");  
        /* 星号表示所有的异域请求都可以接受， */  
        response.setHeader("Access-Control-Allow-Methods", "GET,POST");  
       
        //获取微信小程序get的参数值并打印
        String name = request.getParameter("name");
        
        System.out.println("姓名   =  "+name);
        
        //返回值给微信小程序
        Writer out = response.getWriter(); 
        out.write("后台已连接");
        out.flush();   
    }

	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}