将servelt中的字符串转成json数据传给javascript：ajax

Question

我需要以 ajax 方式提交表单。 当表单提交时，将 servlet 中的字符串转换为 json 数据并将其传递给 javascript 函数，并在每个输入字段下方的错误 div 标记附近分别显示这些错误。

  if(firstparamtr-condition)
    {
        String firsterror = "Error first";

        response.setContentType("application/json");

        response.setHeader("Cache-Control", "no-cache");

        response.setCharacterEncoding("UTF-8");         

        response.getWriter().write(firsterror);       

    }

   if(secondparamtr-condition)
    {
        String seconderror = "Error second";

        response.setContentType("application/json");

        response.setHeader("Cache-Control", "no-cache");

        response.setCharacterEncoding("UTF-8");         

        response.getWriter().write(seconderror);       

    }

javascript代码

 posting.done(function( responseText ) {

   alert(responseText);

//HERE I need to separate the responseText and show that errors in the div tags named 'firstEr' and 'secondEr'      

      });

Answer 1

为了将 String 转换为 JSON，我使用GSON转换器，示例如下：

String string = "example"; // The String which you wish to convert JsonObject convertedObject = new Gson().fromJson(string, JsonObject.class);