前端jQuery使用ajax与后端Servlet进行数据交互

　　前端代码：

$.ajax({
        //直接"post"或者"get",不需要"doPost","doGet"，该函数到后端接收缓冲区会自动匹配
        type : "post",      
        //servlet文件名为Calculator，需要提前在web.xml里面注册
        url : "Calculator", 
        dataType : "text",  //数据类型，可以为json，xml等等，自己百度
        data :
        {
             "operator1" : operator1,        //操作数 
             "operatorSign":operatorSign,     //操作符
             "operator2":operator2            //操作数 
        },
        success : function(Result)
        {
               //Result为后端post函数传递来的数据，这里写结果操作代码
        },
        error : function(xhr, status, errMsg)
        {
             alert("数据传输失败!");
        }
    });

   　后端servlet代码：

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //以下为接收数据
        double operator1 = Double.parseDouble(request.getParameter("operator1"));
        String operatorSign = request.getParameter("operatorSign");
        double operator2 = Double.parseDouble(request.getParameter("operator2"));

        if(operatorSign.equals("+"))
        {
              PrintWriter out = response.getWriter();    //设定传参变量
              out.print(add(operator1, operator2));      //结果传到前端
        }
        else if (operatorSign.equals("-")) 
        {
              PrintWriter out = response.getWriter();
              out.print(sub(operator1, operator2));
        }
        else if (operatorSign.equals("*")) 
        {
              PrintWriter out = response.getWriter();
              out.print(mult(operator1, operator2));
        }
        else if (operatorSign.equals("/")) 
        {
              PrintWriter out = response.getWriter();
              out.print(dev(operator1, operator2));
        }
    }
    public double add(double a,double b) 
    {
        return a+b; 
    }

    public double sub(double a,double b) 
    {
        return a-b; 
    }
    public double mult(double a,double b) 
    {
        return a*b; 
    }
    public double dev(double a,double b) 
    {　　　　//记得b = 0时自己处理
            return a/b; 
    }

 　　　　数据如何传回来，见：http://www.cnblogs.com/Forever-Road/p/6107031.html