在Java中解析JSON数组

Question

我在分析java中的json数组时遇到了问题。

我有一个如下所示的从服务器返回的JSON数组

   [
{
    "User": "538000001",
    "Transaction-Id": "oHbgP2y2OXfdDcxAOI/q9HxY68PNs+xS+8CvfGpoN2ZUU/8mavBaI0564VeZXYBDMnk84kkfZeCJM51I92rFdf4Zi4uKEoqJd7jr78bXo4MOyoSs5mntIir7aVJ9/b+4nz6x2+g0LPY7+Sq8RHvbr+c4Evhg+VXeKDzE3f6+bJo=,YWFhd3MxLnJlYWxtMTsxNDE4MDczNTk0MjkxOzUyQDUzODAwMDAwMQ==",
    "Challenge-Response": "7ZGlkpVfYvQDjvTa2EShZwZ3dGc=",
    "Challenge": "MzcrMzM3NzA4MTM3KzE0MTgwNzM1OTQ="
},
{
    "User": "538000000",
    "Transaction-Id": "+5Oi4NnG9HOVMPx4nM/TP4ZBONG4HtOBbA5+uf/d+hik7o1Aes9H0PLCqAgG/Td2xLDPOdZJJW7ppj3MLkZBvJr+t9JWKdSGpGHAYTp0oonRTVsesPVCtNI6dXvMY9P+bHDiBWkZiqjSjOZuuzImLaJ17G1/D/GNqIonaNCjqjo=,YWFhd3MxLnJlYWxtMTsxNDE4MDczNTk0Mjk1OzUzQDUzODAwMDAwMA==",
    "Challenge-Response": "eEzLzYLmzo5R2tNwokG0mfbuLZY=",
    "Challenge": "MzgrNDY2NjY4NjgyKzE0MTgwNzM1OTQ="
}
]

我正在使用GSON解析这个数组，但到目前为止还不成功。我写了以下代码

     class round1Body
     {
         String User;
         String Transaction_Id;
         String Challenge_Response;
         String Challenge;

         round1Body(String User,String Transaction_Id,String Challenge_Response,String Challenge)
         {
            this.User = User;
            this.Transaction_Id=Transaction_Id;
            this.Challenge_Response = Challenge_Response;
            this.Challenge=Challenge;
         }
         @Override
         public String toString()
        {
            return "User = " + User + " Transaction-Id = " + Transaction_Id + " Challenge-Response = " + Challenge_Response + "Challenge = "
                    + Challenge;
        }
     }
  Type listType = new TypeToken<ArrayList<round1Body>>(){}.getType();
  Object jsonE = new Gson().fromJson(firstResponse.readEntity(String.class),listType);
  System.out.println(jsonE);

当我尝试打印时，输出为null，null。

有人能帮我吗？

提前感谢！

Answer 1

您的firstResponse.readEntity(String.class)调用似乎有问题。否则就不会有[null, null]作为输出。所以问题首先出现在这里。试着让它工作起来。

然后，如果您没有在类的字段上指定SerializedName规则，GSON要求名称必须与JSON文件中的键名称完全匹配。

在JSON端有"Transaction-Id"，但是您在Java文件中将其定义为Transaction_Id，Challenge_Response也是如此。

因为在Java语言中标识符不能有-，所以需要为这两个属性指定一个规则。

class round1Body {
    String User;
    @SerializedName("Transaction-Id")
    String Transaction_Id;
    @SerializedName("Challenge-Response")
    String Challenge_Response;
    String Challenge;
    //...
}

通过这些更改，它可以成功打印(我正在从文件中读取您的JSON字符串)：

[User = 538000001 Transaction-Id = oHbgP2y2OXfdDcxAOI/q9HxY68PNs+xS+8CvfGpoN2ZUU/8mavBaI0564VeZXYBDMnk84kkfZeCJM51I92rFdf4Zi4uKEoqJd7jr78bXo4MOyoSs5mntIir7aVJ9/b+4nz6x2+g0LPY7+Sq8RHvbr+c4Evhg+VXeKDzE3f6+bJo=,YWFhd3MxLnJlYWxtMTsxNDE4MDczNTk0MjkxOzUyQDUzODAwMDAwMQ== Challenge-Response = 7ZGlkpVfYvQDjvTa2EShZwZ3dGc=Challenge = MzcrMzM3NzA4MTM3KzE0MTgwNzM1OTQ=, User = 538000000 Transaction-Id = +5Oi4NnG9HOVMPx4nM/TP4ZBONG4HtOBbA5+uf/d+hik7o1Aes9H0PLCqAgG/Td2xLDPOdZJJW7ppj3MLkZBvJr+t9JWKdSGpGHAYTp0oonRTVsesPVCtNI6dXvMY9P+bHDiBWkZiqjSjOZuuzImLaJ17G1/D/GNqIonaNCjqjo=,YWFhd3MxLnJlYWxtMTsxNDE4MDczNTk0Mjk1OzUzQDUzODAwMDAwMA== Challenge-Response = eEzLzYLmzo5R2tNwokG0mfbuLZY=Challenge = MzgrNDY2NjY4NjgyKzE0MTgwNzM1OTQ=]

请注意，您可以使用此注释来遵守命名约定。