前端jQuery使用ajax與后端Servlet進行數據交互

　　前端代碼：

$.ajax({
        //直接"post"或者"get",不需要"doPost","doGet"，該函數到后端接收緩沖區會自動匹配
        type : "post",      
        //servlet文件名為Calculator，需要提前在web.xml里面注冊
        url : "Calculator", 
        dataType : "text",  //數據類型，可以為json，xml等等，自己百度
        data :
        {
             "operator1" : operator1,        //操作數 
             "operatorSign":operatorSign,     //操作符
             "operator2":operator2            //操作數 
        },
        success : function(Result)
        {
               //Result為后端post函數傳遞來的數據，這里寫結果操作代碼
        },
        error : function(xhr, status, errMsg)
        {
             alert("數據傳輸失敗!");
        }
    });

   　后端servlet代碼：

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //以下為接收數據
        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();    //設定傳參變量
              out.print(add(operator1, operator2));      //結果傳到前端
        }
        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) 
    {　　　　//記得b = 0時自己處理 43             return a/b; 
    }

 　　　　數據如何傳回來，見：http://www.cnblogs.com/Forever-Road/p/6107031.html