JSON与Java对象的互相转换

Posted 2021-01-20 明叶师兄。

JSON与Java对象的互相转换

• 例一（单个对象进行赋值）：

    @RequestMapping("test1.do")
    @ResponseBody
    public JSONObject test1(HttpServletRequest request, HttpServletResponse response) {
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("key1", "value1");
        jsonObject.put("key2", "value2");
        jsonObject.put("key3", "value3");
        return jsonObject;
    }

• 例二（多个对象进行转换）：

    @RequestMapping("TestListQrcode.do")
    @ResponseBody
    public JSONObject TestListQrcode(HttpServletRequest request, HttpServletResponse response)
        throws Exception {
        //String user_phone = request.getParameter("user_phone");
        String user_phone ="13652458975";
  
        Qrcode qrcode = new Qrcode();
        qrcode.setUser_phone(user_phone);
        qrcode.setQrcode_type("普通型");
        List<Qrcode> list  = qrcodeService.selectQrcodeList(qrcode);
  
        //创建json集合
         //用的包：import net.sf.json.JSONArray;
        JSONArray jsonArray = JSONArray.fromObject(list);
        System.out.println(jsonArray.toString());
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("code", 1);
  
        jsonObject.put("data", jsonArray.toString());
        return jsonObject;
    }

• 例三（字符串的拼接，我只在servlet中用过）：

    String value1 = "1";
    int value2 = count-1;
    System.out.println("给前面传的count："+value2);
    String photo_file = par[0] + "/" + par[1] + "/images";
    //进行拼凑json字符串
    String jsonStr =
    "{" + ‘"‘+ "success" + ‘"‘  +":" + ‘"‘ + value1 + ‘"‘ + ","
        + ‘"‘ + "count" + ‘"‘ +":" + ‘"‘ + value2 + ‘"‘ + ","
        + ‘"‘ + "photo_file" + ‘"‘ +":" + ‘"‘ + photo_file + ‘"‘ 
        +"}" ;
    PrintWriter out =null ;
    out =response.getWriter() ;
    out.write(jsonStr);
    out.close();