java - jsp中通过ajax获取json对象

Question

伙计们，我是新来的，所以请帮助我..我试图通过在jsp中使用jqyery ajax来获取json数据..但它不起作用..出现未定义..这是我的代码 在servlet中

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    JSONObject json = null;
    PrintWriter pw = response.getWriter(); 

    try {
        json = new JSONObject();
        json.put("key1", "value1");
        json.put("key2", "value2");
        json.put("key3", "value3");
    } catch (JSONException e) {
        e.printStackTrace();
    }
    response.setContentType("application/json");
    response.setCharacterEncoding("UTF-8");
    pw.print(json.toString());
    pw.close(); 
}

在jsp中

$(document).ready(function(){
    $.ajax({

        url : 'Server',
        type: 'POST',
        dataType : 'json',
        error : function(that,e) {

            console.log(e);
        },
        success : function(data) {
            alert(data.json);
        }
    });

});

Answer 1

你可以使用，

 response.getWriter().write(jsonStr); 
 response.flushBuffer();

因此，通过响应，您可以获得 json 字符串本身

即:

protected void doPost(HttpServletRequest request, 
        HttpServletResponse response) throws ServletException, IOException {

JSONObject json = null;
PrintWriter pw = response.getWriter(); 

try {
    json = new JSONObject();
    json.put("key1", "value1");
    json.put("key2", "value2");
    json.put("key3", "value3");
} catch (JSONException e) {
    e.printStackTrace();
}
    response.setContentType("application/json");
    response.setCharacterEncoding("UTF-8");
    response.getWriter().write(json.toString());
    response.flushBuffer();  //flush the written json string 
    pw.close(); 
}