如何将此 Json 映射到 Gson？
How can I map this Json to Gson?
我正在尝试将此 json 映射到要与 gson 一起使用的对象：
[
{
"code": "USD",
"codein": "BRL",
"name": "Dólar Americano/Real Brasileiro",
"high": "4.133",
"low": "4.133",
"varBid": "0.0004",
"pctChange": "0.01",
"bid": "4.1326",
"ask": "4.1333",
"timestamp": "1579036500",
"create_date": "2020-01-14 18:15:00"
},
{
"high": "4.1613",
"low": "4.1227",
"varBid": "-0.0124",
"pctChange": "-0.3",
"bid": "4.134",
"ask": "4.1345",
"timestamp": "1579036447"
},
{
"high": "4.1613",
"low": "4.1227",
"varBid": "-0.0146",
"pctChange": "-0.35",
"bid": "4.1318",
"ask": "4.1323",
"timestamp": "1579036270"
},
{
"high": "4.1613",
"low": "4.1227",
"varBid": "-0.0137",
"pctChange": "-0.33",
"bid": "4.1326",
"ask": "4.1333",
"timestamp": "1579036059"
},
{
"high": "4.1613",
"low": "4.1227",
"varBid": "-0.0139",
"pctChange": "-0.33",
"bid": "4.1325",
"ask": "4.133",
"timestamp": "1579035872"
}
]
项目运行正常，但当我尝试访问端点时出现此错误：
com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:226)
at com.google.gson.Gson.fromJson(Gson.java:932)
at com.google.gson.Gson.fromJson(Gson.java:897)
at com.google.gson.Gson.fromJson(Gson.java:846)
at com.google.gson.Gson.fromJson(Gson.java:817)
at br.com.leomanzini.dollar.price.service.DollarPriceService.getHistoryDollarPrice(DollarPriceService.java:66)
at br.com.leomanzini.dollar.price.controller.DollarPriceController.getHistoryDollarPrice(DollarPriceController.java:28)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:655)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1726)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $
at com.google.gson.stream.JsonReader.beginObject(JsonReader.java:384)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:215)
调试项目我看到报错的那一行是代码中标有错误注释的那一行，这可能是映射？我怎样才能正确映射这个对象？
已映射 class:
package br.com.leomanzini.dollar.price.dto.response;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class HistoryDollarResponse {
private String pctChange;
private String bid;
private String timestamp;
}
挖矿功能：
public HistoryDollarResponse getHistoryDollarPrice(String day, String month, String year) throws Exception {
try {
PropertiesLoader.load();
String date = year + month + day;
String serviceUrl = PropertiesLoader.getHistoryUrl();
serviceUrl = String.format(serviceUrl, date);
URL url = new URL(serviceUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
if (connection.getResponseCode() != 200) {
throw new RuntimeException("HTTP error code : " + connection.getResponseCode());
}
BufferedReader response = new BufferedReader(new InputStreamReader((connection.getInputStream())));
String jsonToString = Convert.jsonIntoString(response);
Gson gson = new Gson();
HistoryDollarResponse returnObject = gson.fromJson(jsonToString, HistoryDollarResponse.class); //error
return returnObject;
} catch (Exception e) {
e.printStackTrace();
throw new Exception("Can't access the webpage");
}
}
谁能帮助我，我将不胜感激！！
请检查一下，
String DB_JSON_FORMATE_1 = "yyyy-MM-dd'T'HH:mm:ss.SSS";
GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.setDateFormat(DB_JSON_FORMATE_1);
Gson gson = gsonBuilder.create();
Type listType = new TypeToken<List<HistoryDollarResponse>>() {}.getType();
List<HistoryDollarResponse> historyDollarResponse = gson.fromJson(#PASS_YOU_STING#, listType);
您设置了日期格式并且 POJO 使用注释 @JsonSerialize(using=DateSerializer.class)
我不确定我的回答是否适合您，请尝试提供帮助。
{
“高”：“4.1613”，
“低”：“4.1227”，
"varBid": "-0.0146",
"pctChange": "-0.35",
“出价”：“4.1318”，
“问”：“4.1323”，
“时间戳”：“1579036270”
}
public class Staff {
private String high;
private String low;
private String varBid;
private String pctChange;
private String bid;
private String ask;
private String timestamp;
}
Gson gson = new Gson();
// JSON string to Java object
// this is example like your json
//String json = "{'name' : 'mkyong'}";
Staff staff = gson.fromJson(json, Staff.class);
in your json syntax, it is about timestamp, if you need or want, you should be convert them to int, double, float and timestramp
for example Timestamp.valueOf("2018-11-12 01:02:03.123456789") you can search out lots about string to int, float or double.
我正在尝试将此 json 映射到要与 gson 一起使用的对象：
[
{
"code": "USD",
"codein": "BRL",
"name": "Dólar Americano/Real Brasileiro",
"high": "4.133",
"low": "4.133",
"varBid": "0.0004",
"pctChange": "0.01",
"bid": "4.1326",
"ask": "4.1333",
"timestamp": "1579036500",
"create_date": "2020-01-14 18:15:00"
},
{
"high": "4.1613",
"low": "4.1227",
"varBid": "-0.0124",
"pctChange": "-0.3",
"bid": "4.134",
"ask": "4.1345",
"timestamp": "1579036447"
},
{
"high": "4.1613",
"low": "4.1227",
"varBid": "-0.0146",
"pctChange": "-0.35",
"bid": "4.1318",
"ask": "4.1323",
"timestamp": "1579036270"
},
{
"high": "4.1613",
"low": "4.1227",
"varBid": "-0.0137",
"pctChange": "-0.33",
"bid": "4.1326",
"ask": "4.1333",
"timestamp": "1579036059"
},
{
"high": "4.1613",
"low": "4.1227",
"varBid": "-0.0139",
"pctChange": "-0.33",
"bid": "4.1325",
"ask": "4.133",
"timestamp": "1579035872"
}
]
项目运行正常，但当我尝试访问端点时出现此错误：
com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:226)
at com.google.gson.Gson.fromJson(Gson.java:932)
at com.google.gson.Gson.fromJson(Gson.java:897)
at com.google.gson.Gson.fromJson(Gson.java:846)
at com.google.gson.Gson.fromJson(Gson.java:817)
at br.com.leomanzini.dollar.price.service.DollarPriceService.getHistoryDollarPrice(DollarPriceService.java:66)
at br.com.leomanzini.dollar.price.controller.DollarPriceController.getHistoryDollarPrice(DollarPriceController.java:28)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:655)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1726)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $
at com.google.gson.stream.JsonReader.beginObject(JsonReader.java:384)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:215)
调试项目我看到报错的那一行是代码中标有错误注释的那一行，这可能是映射？我怎样才能正确映射这个对象？
已映射 class:
package br.com.leomanzini.dollar.price.dto.response;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class HistoryDollarResponse {
private String pctChange;
private String bid;
private String timestamp;
}
挖矿功能：
public HistoryDollarResponse getHistoryDollarPrice(String day, String month, String year) throws Exception {
try {
PropertiesLoader.load();
String date = year + month + day;
String serviceUrl = PropertiesLoader.getHistoryUrl();
serviceUrl = String.format(serviceUrl, date);
URL url = new URL(serviceUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
if (connection.getResponseCode() != 200) {
throw new RuntimeException("HTTP error code : " + connection.getResponseCode());
}
BufferedReader response = new BufferedReader(new InputStreamReader((connection.getInputStream())));
String jsonToString = Convert.jsonIntoString(response);
Gson gson = new Gson();
HistoryDollarResponse returnObject = gson.fromJson(jsonToString, HistoryDollarResponse.class); //error
return returnObject;
} catch (Exception e) {
e.printStackTrace();
throw new Exception("Can't access the webpage");
}
}
谁能帮助我，我将不胜感激！！
请检查一下，
String DB_JSON_FORMATE_1 = "yyyy-MM-dd'T'HH:mm:ss.SSS";
GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.setDateFormat(DB_JSON_FORMATE_1);
Gson gson = gsonBuilder.create();
Type listType = new TypeToken<List<HistoryDollarResponse>>() {}.getType();
List<HistoryDollarResponse> historyDollarResponse = gson.fromJson(#PASS_YOU_STING#, listType);
您设置了日期格式并且 POJO 使用注释 @JsonSerialize(using=DateSerializer.class)
我不确定我的回答是否适合您，请尝试提供帮助。
{ “高”：“4.1613”， “低”：“4.1227”， "varBid": "-0.0146", "pctChange": "-0.35", “出价”：“4.1318”， “问”：“4.1323”， “时间戳”：“1579036270” }
public class Staff {
private String high;
private String low;
private String varBid;
private String pctChange;
private String bid;
private String ask;
private String timestamp;
}
Gson gson = new Gson();
// JSON string to Java object
// this is example like your json
//String json = "{'name' : 'mkyong'}";
Staff staff = gson.fromJson(json, Staff.class);
in your json syntax, it is about timestamp, if you need or want, you should be convert them to int, double, float and timestramp
for example Timestamp.valueOf("2018-11-12 01:02:03.123456789") you can search out lots about string to int, float or double.