在Java中将字符串转换为Json数组时获得空Json数组

我正在尝试将字符串转换为Json数组（不带名称/标记），并遍历结果数组。。但在调试代码时，生成的json数组显示为null。我找不到这个问题的原因

下面是我试图解析为Json数组的给定字符串

String jsonString="[ {"
            + "\"TimeStamp\": \"20:10\","
            + "\"PipeTemp\": \"31.5\","
            + "\"ChocolateMixingTemp\": \"25\","
            + "\"WaterCoolingTemp\": \"5\","
            + "\"WaterMixingTemp\": \"0\","
            + "\"WaterHeatingTemp\": \"0\",},
            +{"
            + "\"TimeStamp\": \"20:00\","
            + "\"PipeTemp\": \"35.5\","
            + "\"ChocolateMixingTemp\": \"28\","
            + "\"WaterCoolingTemp\": \"3\","
            + "\"WaterMixingTemp\": \"15\","
            + "\"WaterHeatingTemp\": \"0\","
            +}]";

我将上述字符串传递给Java数组实例，然后使用for循环对其进行迭代以生成PDF表。但当我尝试检查Json数组的大小时，它显示为null

JSONArray jsonArray = new JSONArray(jsonString);

 JSONObject jsonObject;
 for(int n = 0; n < jsonArray.length(); n++)
{
 table.addCell(createCell( (String) jsonObject.get("TimeStamp"),Element.ALIGN_CENTER)); 
             table.addCell(createCell( (String) jsonObject.get("PipeTemp"),Element.ALIGN_CENTER)); 
             table.addCell(createCell( (String) jsonObject.get("ChocolateMixingTemp"), Element.ALIGN_CENTER)); 
             table.addCell(createCell( (String) jsonObject.get("WaterCoolingTemp"),Element.ALIGN_CENTER)); 
             table.addCell(createCell( (String) jsonObject.get("WaterMixingTemp"),Element.ALIGN_CENTER)); 
jsonObject.get("WaterHeatingTemp"),Element.ALIGN_CENTER)); 

}

JSONArray-JSONArray=新的JSONArray（jsonString）；
JSONObject JSONObject；
for（int n=0；n

有人能帮我确定为什么数组显示为空吗？

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我还尝试使用一个只包含两个键值对的简单字符串进行测试。但是得到了同样的结果。

您的代码是错误的。请尝试以下代码来测试JSON数组：

String jsonString = "[ {"
            + "\"TimeStamp\": \"20:10\","
            + "\"PipeTemp\": \"31.5\","
            + "\"ChocolateMixingTemp\": \"25\","
            + "\"WaterCoolingTemp\": \"5\","
            + "\"WaterMixingTemp\": \"0\","
            + "\"WaterHeatingTemp\": \"0\",},"
            + "{"
            + "\"TimeStamp\": \"20:00\","
            + "\"PipeTemp\": \"35.5\","
            + "\"ChocolateMixingTemp\": \"28\","
            + "\"WaterCoolingTemp\": \"3\","
            + "\"WaterMixingTemp\": \"15\","
            + "\"WaterHeatingTemp\": \"0\","
            + "}]";

JSONArray jsonArray = new JSONArray(jsonString);

System.out.println(jsonArray);

for (int n = 0; n < jsonArray.length(); n++) {
    JSONObject jsonObject = jsonArray.getJSONObject(n);
    System.out.println((String) jsonObject.get("TimeStamp"));
}

String jsonString=“[{”
+“\“时间戳\：\“20:10\”，”
+“\“PipeTemp\”：\“31.5\”，”
+“巧克力混合汤”：“25”
+“\'WaterCoolingTemp\”：\'5\”
+“\'WaterMixingTemp\”：\'0\，”
+“WaterHeatingTemp\：\“0\，}”
+ "{"
+“\“时间戳\：\“20:00\”，”
+“\“PipeTemp\”：\“35.5\”，”
+“巧克力混合汤”：“28”
+“\'WaterCoolingTemp\”：\'3\，”
+“\'WaterMixingTemp\”：\'15\，”
+“\“WaterHeatingTemp\”：\“0\”
+ "}]";
JSONArray JSONArray=新的JSONArray（jsonString）；
System.out.println（jsonArray）；
for（int n=0；n

首先，您的json字符串格式不正确，请参见下面的格式：

String s="[ {"
                + "\"TimeStamp\": \"20:10\","
                + "\"PipeTemp\": \"31.5\","
                + "\"ChocolateMixingTemp\": \"25\","
                + "\"WaterCoolingTemp\": \"5\","
                + "\"WaterMixingTemp\": \"0\","
                + "\"WaterHeatingTemp\": \"0\",},"
                + "{"
                + "\"TimeStamp\": \"20:00\","
                + "\"PipeTemp\": \"35.5\","
                + "\"ChocolateMixingTemp\": \"28\","
                + "\"WaterCoolingTemp\": \"3\","
                + "\"WaterMixingTemp\": \"15\","
                + "\"WaterHeatingTemp\": \"0\","
                + "}]";

第二，我没有看到您的jsonObject被任何东西初始化。

---

如果您想使用json中的值，请使用jsonArray.get（index）方法。

您的json可能会有问题，另外还有一个逗号（，）+“\”WaterHeatingTemp\”：\“0\”，>>应该没有逗号（，）“\”WaterHeatingTemp\“：\”0\”json中肯定有一些输入错误，它不会为我编译。它很容易通过Stackoverflow的语法突出显示看到。您会立即看到

WaterHeatingTemp

附近有一个问题。