Why this Json cannot be resolved from the HTTP request?

Question

My code is based on SpringBoot, receives post request, resolves the json data and the use jdbc to execute.

public class ETLController {
@Autowired
@Qualifier("ETLService")
private ETLServiceImpl ETLServiceImpl;

@RequestMapping(value = "/sql", method = RequestMethod.POST)
@ResponseBody
/**
 * @param sqlString 
 */    
public String identify(HttpServletRequest request) {

    //String sqlString, int maxRowNum, int maxColumnNum, int maxDuration, long startTime, String killQueryJob, int processResult
    System.out.println("request: "+request) ;
    String requestJson = request.getParameter("parametersJson");
    System.out.println("requestJson: "+requestJson) ;

    //Json parser
    JsonObject object = Json.parse(requestJson).asObject();

    //connection parameters
    String connString = object.get("connString").asString();
    String connUserName = object.get("connUserName").asString();
    String connPassWord = object.get("connPassWord").asString();

    //HQL query parameter
    String sqlString = object.get("sqlString").asString();
    int maxRowNum = object.get("maxRowNum").asInt();
    int maxColumnNum = object.get("maxColumnNum").asInt();
    int maxDuration = object.get("maxDuration").asInt();

    String sqlResult = ETLServiceImpl.executeShellScript(connString, connUserName, connPassWord, sqlString, maxRowNum, maxColumnNum, maxDuration);
    return sqlResult;
}

}

The curl command is as follows:

curl -H "Content-Type: application/json" -X POST  --data  '{"sqlString":"select room_id from dim.dim_room","connString":"jdbc:hive2://192.168.7.21:10001/","connUserName":"xxxx","connPassWord":"xxxx","maxRowNum":500,"maxColumnNum":10,"maxDuration":6000}' http://192.168.7.24:xxx/etl/sql

However, when I send the post request via curl, the parameter cannot be resolved and the requestJson is always null.

Why does this issue happen and how to address it?

The stacktrace:

2017-11-03 14:45:32.290 ERROR 181818 --- [nio-9162-exec-7] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException: string is null] with root cause

java.lang.NullPointerException: string is null
        at com.eclipsesource.json.Json.parse(Json.java:292) ~[minimal-json-0.9.4.jar!/:na]
        at com.lz.web.action.etl.ETLController.identify(ETLController.java:39) ~[classes!/:1.0-SNAPSHOT]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_101]
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_101]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
        at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97) ~[spring-webmvc-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967) ~[spring-webmvc-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) ~[spring-webmvc-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872) ~[spring-webmvc-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:661) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:105) ~[spring-web-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.10.RELEASE.jar!/:4.3.10.RELEASE]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) [tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80) [tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799) [tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455) [tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_101]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_101]
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.16.jar!/:8.5.16]
        at java.lang.Thread.run(Thread.java:745) [na:1.8.0_101]

You should decide whether you wish to send a POST request or a GET request. Your curl input is wrong for POST requests (it shouldn't contain parameter name such as "parametersJson", it should only contain the JSON content), and your server looks for a parameter as if it expects a GET request. — Eran, Nov 03 '17 at 07:31
Possible duplicate of [Trying to use Spring Boot REST to Read JSON String from POST](https://stackoverflow.com/questions/29313687/trying-to-use-spring-boot-rest-to-read-json-string-from-post) — Arnaud, Nov 03 '17 at 07:32
@Eran Thx for your reply. The command didn't contain the parameter name at first, but didn't work. — SuperDelta, Nov 03 '17 at 07:41
@SuperDelta because you are sending a POST request but your server seems to expect a GET request. — Eran, Nov 03 '17 at 07:44
@SuperDelta please try the answer given by me. It will work for you. Thank You for updating your stacktrace :) — Vikrant Kashyap, Nov 03 '17 at 07:52
@VikrantKashyap yes! thx for your code! I've learnt something! — SuperDelta, Nov 03 '17 at 09:15

Vikrant Kashyap · Accepted Answer · 2017-11-03T07:54:50.933

make a Pojo Class with class member which should be same as the keys available in the JSON you pass.

public class ConnectionString{

    private String sqlString;
    private String connString;
    private String connUserName;
    private String connPassWord; 
    private Long maxRowNum ;
    private Long maxColumnNum;
    private Long maxDuration;

    //all getters and setters.
  }

Now do a simple change in your method identify() to receive it directly as a Java Object.

try this method definition (see changed parameter)

public String identify(HttpServletRequest request, @RequestBody ConnectionString connectionString){

  //here how receive your data you passed using curl.
   System.out.println(connectionString.getSqlString());

   // this will print the value you passed as a body.
}

you also need to edit your curl body json data you passed like remove the key parametersJson

try this

'{"sqlString":"select room_id from dim.dim_room","connString":"jdbc:hive2://192.168.7.21:10001/","connUserName":"xxxx","connPassWord":"xxxx","maxRowNum":500,"maxColumnNum":10,"maxDuration":6000}'

instead of

'parametersJson='{"sqlString":"select room_id from dim.dim_room","connString":"jdbc:hive2://192.168.7.21:10001/","connUserName":"xxxx","connPassWord":"xxxx","maxRowNum":500,"maxColumnNum":10,"maxDuration":6000}''

Note - Spring automatically change you requestbody data into the JavaObject. Spring internally used jackson-databind jar classes to perform this. :)

score 0 · Answer 2 · edited Nov 03 '17 at 07:29

0

Can try below

curl -H "Content-Type: application/json" -X POST  -d  '{"sqlString":"select room_id from dim.dim_room","connString":"jdbc:hive2://192.168.7.21:10001/","connUserName":"magic","connPassWord":"w8spDGCJVMG3J2MWio5X","maxRowNum":500,"maxColumnNum":10,"maxDuration":6000}' http://192.168.7.24:xxx/etl/sql

edited Nov 03 '17 at 07:29

AxelH

14,325
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answered Nov 03 '17 at 07:27

sbhargavs

1
2

You should explain what you have update and why you believe this would work – AxelH Nov 03 '17 at 07:29

score 0 · Answer 3 · edited Nov 03 '17 at 08:16

0

Try with:

public String identify(HttpServletRequest request, @RequestBody String parametersJson){...}

edited Nov 03 '17 at 08:16

4b0

21,981
30
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142

answered Nov 03 '17 at 07:28

Bikramjit Rajbongshi

422
3
10

if you receive it as a `String` then it need to be converted into a `Java Object ` to perform further tasks. Thank You :) – Vikrant Kashyap Nov 03 '17 at 07:50
Yes. Anyway you are doing same JsonObject object = Json.parse(requestJson).asObject(); – Bikramjit Rajbongshi Nov 03 '17 at 08:55

Why this Json cannot be resolved from the HTTP request?

3 Answers3