Java 将 InputStream 转换为 JSON
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Convert InputStream into JSON
提问by Margi
I am using json-rpc-1.0.jar.Below is my code. I need to convert InputStream object into JSON since the response is in JSON.
我正在使用 json-rpc-1.0.jar.Below 是我的代码。我需要将 InputStream 对象转换为 JSON，因为响应是 JSON。
I did verify the json response obtained from Zappos API. It is valid.
我确实验证了从 Zappos API 获得的 json 响应。这是有效的。
PrintWriter out = resp.getWriter();
String jsonString = null;
URL url = new URL("http://api.zappos.com/Search?term=boots&key=my_key");
InputStream inputStream = url.openConnection().getInputStream();
resp.setContentType("application/json");
JSONSerializer jsonSerializer = new JSONSerializer();
try {
jsonString = jsonSerializer.toJSON(inputStream);
} catch (MarshallException e) {
e.printStackTrace();
}
out.print(jsonString);
I get the below mentioned exception:
我得到以下提到的异常：
com.metaparadigm.jsonrpc.MarshallException: can't marshall sun.net.www.protocol.http.HttpURLConnection$HttpInputStream
at com.metaparadigm.jsonrpc.JSONSerializer.marshall(JSONSerializer.java:251)
at com.metaparadigm.jsonrpc.JSONSerializer.toJSON(JSONSerializer.java:259)
at Communicator.doGet(Communicator.java:33)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at filters.ExampleFilter.doFilter(ExampleFilter.java:149)
采纳答案by Vishal Pawale
Make use of Hymanson JSON parser.
使用 Hymanson JSON 解析器。
Refer - Hymanson Home
参考 -Hyman逊之家
The only thing you need to do -
你唯一需要做的——
ObjectMapper mapper = new ObjectMapper();
Map<String, Object> jsonMap = mapper.readValue(inputStream, Map.class);
Now jsonMapwill contain the JSON.
现在jsonMap将包含 JSON。
回答by Philip Rego
ObjectMapper.readTree(InputStream) easily let's you get nested JSON with JsonNodes.
ObjectMapper.readTree(InputStream) 让我们轻松地使用 JsonNodes 获得嵌套的 JSON。
public void testMakeCall() throws IOException {
URL url = new URL("https://api.coindesk.com/v1/bpi/historical/close.json?start=2010-07-17&end=2018-07-03");
HttpURLConnection httpcon = (HttpURLConnection) url.openConnection();
httpcon.addRequestProperty("User-Agent", "Mozilla/4.0");
InputStream is = httpcon.getInputStream();
try {
ObjectMapper mapper = new ObjectMapper();
JsonNode jsonMap = mapper.readTree(is);
JsonNode bpi = jsonMap.get("bpi");
JsonNode day1 = bpi.get("2010-07-18");
System.out.println(bpi.toString());
System.out.println(day1.toString());
} finally {
is.close();
}
}
Result:
结果：
{"2010-07-18":0.0858,"2010-07-19":0.0808,...}
0.0858
{"2010-07-18":0.0858,"2010-07-19":0.0808,...}
0.0858
回答by Alex
Better to save memory by having output as Stream<JsonNode>
通过输出为更好地节省内存 Stream<JsonNode>
private fun InputStream.toJsonNodeStream(): Stream<JsonNode> {
return StreamSupport.stream(
Spliterators.spliteratorUnknownSize(this.toJsonNodeIterator(), Spliterator.ORDERED),
false
)
}
private fun InputStream.toJsonNodeIterator(): Iterator<JsonNode> {
val jsonParser = objectMapper.factory.createParser(this)
return object: Iterator<JsonNode> {
override fun hasNext(): Boolean {
var token = jsonParser.nextToken()
while (token != null) {
if (token == JsonToken.START_OBJECT) {
return true
}
token = jsonParser.nextToken()
}
return false
}
override fun next(): JsonNode {
return jsonParser.readValueAsTree()
}
}
}
