如果找不到内容变量，怎么办？
JSON
{
"transcript": {
"text": [
{
"content": "Tonight we're running on the right track",
"dur": "2",
"start": "2.649"
},
{
"dur": "0.5",
"start": "4.649"
},
{
"dur": "0.5",
"start": "5.149"
},
{
"dur": "0.5",
"start": "5.649"
},
{
"dur": "0.5",
"start": "7.1"
},
{
"content": "I know we're never look back",
"dur": "1.04",
"start": "7.6"
},
{
"content": "Oh i",
"dur": "0.5",
"start": "12.3"
},
{
"content": "just want to have a good time",
"dur": "2.16",
"start": "12.92"
},
{
"content": "Call me or Whatever",
"dur": "2",
"start": "15.2"
},
{
"content": "some ### will anything life back",
"dur": "2.8",
"start": "17.2"
},
{
"content": "Oh no",
"dur": "2",
"start": "20.88"
},
{
"content": "we don't want to be",
"dur": "1.2",
"start": "22.96"
},
{
"content": "Sloomo",
"dur": "0.8",
"start": "24.16"
},
{
"content": "so my #### says",
"dur": "1.44",
"start": "25.52"
},
{
"content": "Let's Go",
"dur": "2",
"start": "26.96"
},
{
"content": "To the beat and sweet and sweet",
"dur": "2",
"start": "28.96"
},
{
"content": "and see me like",
"dur": "2",
"start": "30.96"
},
{
"content": "see me like",
"dur": "2",
"start": "33.56"
},
{
"content": "Party like",
"dur": "2",
"start": "35.96"
},
{
"content": "Breaking up\nTo the beat like see me like",
"dur": "2.34",
"start": "38.26"
},
{
"content": "Pencil or no pencil pencil?",
"dur": "1.26",
"start": "48.08"
},
{
"content": "Pencil.",
"dur": "1.16",
"start": "51.92"
},
{
"content": "Do you want Steve in the background?",
"dur": "2",
"start": "58.04"
},
{
"content": "I don't know. Does he deserve it?",
"dur": "3.14",
"start": "61.72"
},
{
"content": "My phone buzzered every time you tagged me.",
"dur": "3.44",
"start": "65.1"
},
{
"content": "Maybe someday, I'll let you be my real boyfriend.",
"dur": "2.42",
"start": "75.76"
},
{
"content": "You love it.",
"dur": "2",
"start": "78.18"
},
{
"content": "Free phone ? Once I hit 2,000.",
"dur": "2",
"start": "83.36"
},
{
"content": ""That's that's totally doable." "Just a matter of time." "Your, your first brand deal."",
"dur": "6.22",
"start": "86.68"
},
{
"content": "Drop this off at the library, I hate going in there. Of course. Deuces!",
"dur": "6.64",
"start": "95.66"
},
{
"content": "Jen ?",
"dur": "0.5",
"start": "102.56"
},
{
"content": "We don't say that anymore.",
"dur": "2",
"start": "105.02"
},
{
"content": "Right. See ya!",
"dur": "2",
"start": "108.38"
},
{
"content": "So, what do you think?",
"dur": "2",
"start": "115.58"
},
{
"content": ""Who did them?" "Me!" "How old were you?" "I worked on 'em this week."",
"dur": "6.52",
"start": "122.84"
},
{
"content": "Oh.",
"dur": "0.84",
"start": "130.96"
},
{
"content": "Yeah, I'm thinking of changing electives, next term maybe taking art.",
"dur": "4.4",
"start": "133.2"
},
{
"content": "Okay.",
"dur": "3.21",
"start": "149.42"
},
{
"content": "Uhm, no.",
"dur": "2",
"start": "152.63"
},
{
"content": ""I'm just starting." "And now it's time to stop." "This...isn't you."",
"dur": "7.52",
"start": "156.08"
},
{
"content": "These are bad.",
"dur": "2",
"start": "164.93"
},
{
"content": "Okay.",
"dur": "1.89",
"start": "169.7"
},
{
"content": "You have to stay in the classes that I'm taking. I need you there. I mean...",
"dur": "5.18",
"start": "171.59"
},
{
"content": "Who else is gonna tell me how pretty I am?",
"dur": "2.059",
"start": "177.68"
},
{
"content": "Yeah",
"dur": "2",
"start": "181.16"
},
{
"content": ""Probably everybody" "Probably, but still I can't have an artsy boyfriend."",
"dur": "6.11",
"start": "183.44"
},
{
"content": "So I am the boyfriend ?",
"dur": "2",
"start": "191.84"
},
{
"content": "I know we're so cute together. I'm just contouring. *laughs* He's five months older.",
"dur": "7.489",
"start": "199.88"
},
{
"content": "I straighten my hair?",
"dur": "2",
"start": "209.93"
},
{
"content": "I am not telling you where I live.",
"dur": "2.149",
"start": "214.19"
},
{
"content": ""Hey, Nikki. Have you seen the remote?" "I don't watch TV, Dad!"",
"dur": "4.4",
"start": "217.7"
},
{
"content": "Your mom's missing the Kardashians.",
"dur": "2",
"start": "222.77"
},
{
"content": ""Mom's missing the Kardashians?"",
"dur": "2.92",
"start": "225.4"
},
{
"content": ""Yeah, can you help us find the remote please.""
}
]
}
}
代码
try {
JSONObject jsonObject = new JSONObject(String.valueOf(xmlToJson));
JSONObject transcript = jsonObject.getJSONObject("transcript");
JSONArray jsonArray = transcript.getJSONArray("text");
for (int x = 0; x < jsonArray.length(); x++) {
test += " " + jsonArray.getJSONObject(x).getString("content") + " ";
}
} catch (JSONException e) {
e.printStackTrace();
}
错误
org.json.JSONException: No value for content
我在这行中有一个错误
test += " " + jsonArray.getJSONObject(x).getString("content") + " ";
非常感谢。
答案 0 :(得分：1)
您有多种方法可以做到这一点，
我建议不要检查它，而只需使用以下内容获取值
optString()
代替getString，当内容不存在时不会抛出异常
如果您仍然要检查，JSONObject有一个方法
boolean has(String name)
此方法将告诉您密钥是否存在
以下代码应该可以正常工作
try {
JSONObject jsonObject = new JSONObject(String.valueOf(xmlToJson));
JSONObject transcript = jsonObject.getJSONObject("transcript");
JSONArray jsonArray = transcript.getJSONArray("text");
JSONObject temp;
for (int x = 0; x < jsonArray.length(); x++) {
temp = jsonArray.getJSONObject(x);
if(temp.has("content")){
test += " " + temp.getString("content") + " ";
}
}
} catch (JSONException e) {
e.printStackTrace();
}
我将使用的替代方法是：
try {
JSONObject jsonObject = new JSONObject(String.valueOf(xmlToJson));
JSONObject transcript = jsonObject.getJSONObject("transcript");
JSONArray jsonArray = transcript.getJSONArray("text");
for (int x = 0; x < jsonArray.length(); x++) {
test += " " + jsonArray.getJSONObject(x).optString("content") + " ";
}
} catch (JSONException e) {
e.printStackTrace();
}
答案 1 :(得分：1)
尝试使用像
因此，请尝试将解析数据与示例jsonObject.optJsonObject("LatLng")，optString()
也使用not null条件
答案 2 :(得分：1)
尝试此代码
<td [innerHTML]="callTree.contact | safeHtml"></td>
答案 3 :(得分：0)
您可以使用has来检查可用性
.has(name)
您可以使用
检查无效性.get(name).isJsonNull
我通常使用BaseDeserializer来检查参数
open class BaseDeserializer {
fun check(json: JsonObject, name: String): Boolean {
return hashValue(json, name) && checkValue(json, name)
}
private fun checkValue(json: JsonObject, name: String): Boolean {
return !json.get(name).isJsonNull
}
private fun hashValue(json: JsonObject, name: String): Boolean {
return json.has(name)
}
}
更新
更新了给定的示例。
try {
JSONObject jsonObject = new JSONObject(String.valueOf(xmlToJson));
JSONObject transcript = jsonObject.getJSONObject("transcript");
JSONArray jsonArray = transcript.getJSONArray("text");
for (int x = 0; x < jsonArray.length(); x++) {
JSONObject item = jsonArray.getJSONObject(x);
if(check(item, "content") {
test += " " + jsonArray.getJSONObject(x).getString("content") + " ";
}
}
} catch (JSONException e) {
e.printStackTrace();
}
在.isJsonNull类型中，.isJsonNull()在Kotlin中也等效于JsonElement
答案 4 :(得分：0)
您拥有的json条目
{
"dur": "0.5",
"start": "4.649"
},
{
"dur": "0.5",
"start": "5.149"
},
{
"dur": "0.5",
"start": "5.649"
},
{
"dur": "0.5",
"start": "7.1"
},
{
"content": "I know we're never look back",
"dur": "1.04",
"start": "7.6"
}
其中一些条目中没有变量content，因此在尝试访问它时会引发错误。
您可以做的就是添加if支票。
for (int x = 0; x < jsonArray.length(); x++) {
JSONObject jsonObj = jsonArray.getJSONObject(x);
if(jsonObj.has("content"){
test += " " + jsonObj.getString("content") + " ";
}
}