Trying to use Spring Boot REST to Read JSON String from POST

Question

Am using the latest version of Spring Boot to read in a sample JSON via Restful Web Service     Here s my pom xml    lt  xml version  1 0  encoding  UTF-8   gt   lt project xmlns  http   maven apache org POM 4 0 0                  xsi schemaLocation  http   maven apache org POM 4 0 0           http   maven apache org maven-v4 0 0 xsd           xmlns xsi  http   www w3 org 2001 XMLSchema-instance  gt        lt modelVersion gt 4 0 0 lt  modelVersion gt        lt groupId gt org springframework lt  groupId gt       lt artifactId gt myservice lt  artifactId gt       lt version gt 0 1 0 lt  version gt        lt parent gt           lt groupId gt org springframework boot lt  groupId gt           lt artifactId gt spring-boot-starter-parent lt  artifactId gt           lt version gt 1 2 2 RELEASE lt  version gt       lt  parent gt        lt properties gt           lt java version gt 1 7 lt  java version gt           lt project build sourceEncoding gt UTF-8 lt  project build sourceEncoding gt           lt project reporting outputEncoding gt UTF-8 lt  project reporting outputEncoding gt       lt  properties gt        lt dependencies gt           lt dependency gt               lt groupId gt org springframework boot lt  groupId gt               lt artifactId gt spring-boot-starter-web lt  artifactId gt           lt  dependency gt           lt dependency gt               lt groupId gt org springframework boot lt  groupId gt               lt artifactId gt spring-boot-starter-test lt  artifactId gt               lt scope gt test lt  scope gt           lt  dependency gt           lt dependency gt               lt groupId gt org springframework data lt  groupId gt               lt artifactId gt spring-data-rest-webmvc lt  artifactId gt           lt  dependency gt           lt dependency gt       lt  dependencies gt        lt build gt           lt plugins gt               lt plugin gt                   lt groupId gt org springframework boot lt  groupId gt                   lt artifactId gt spring-boot-maven-plugin lt  artifactId gt               lt  plugin gt           lt  plugins gt       lt  build gt        lt repositories gt           lt repository gt               lt id gt spring-releases lt  id gt               lt name gt Spring Releases lt  name gt               lt url gt https   repo spring io libs-release lt  url gt           lt  repository gt           lt repository gt               lt id gt org jboss repository releases lt  id gt               lt name gt JBoss Maven Release Repository lt  name gt               lt url gt https   repository jboss org nexus content repositories releases lt  url gt           lt  repository gt       lt  repositories gt        lt pluginRepositories gt           lt pluginRepository gt               lt id gt spring-releases lt  id gt               lt name gt Spring Releases lt  name gt               lt url gt https   repo spring io libs-release lt  url gt           lt  pluginRepository gt       lt  pluginRepositories gt    lt  project gt    Here s my web service code   import org springframework web bind annotation RequestBody  import org springframework web bind annotation RequestMapping  import org springframework web bind annotation RequestMethod  import org springframework web bind annotation RestController    RestController  RequestMapping   myservice   public class BaseService           RequestMapping value   process   method   RequestMethod POST      public void process  RequestBody String payload  throws Exception           System out println payload             When I invoke it using the following command   curl -H  Accept  application json  -H  Content-type  application json   -X POST -d    name   value    http   localhost 8080 myservice process   I get this error message     timestamp  1427515733546  status  400    error   Bad Request     exception    org springframework http converter HttpMessageNotReadableException     message     Could not read JSON  Can not deserialize instance of java lang String   out of START OBJECT token n at     Source  java io PushbackInputStream 8252f  line  1  column  1      nested    exception is com fasterxml jackson databind JsonMappingException    Can not deserialize instance of java lang String out of START OBJECT token n       at  Source  java io PushbackInputStream 8252f  line  1  column  1       path    myservice process    The only thing I am trying to do is pass in some valid JSON  as a string via curl  and to see if the String payload enters the process method as   name   value    What am I possibly doing wrong   Thank you for taking the time to read this

User · Answer

To receive arbitrary Json in Spring-Boot  you can simply use Jackson s JsonNode  The appropriate converter is automatically configured        PostMapping value   process       public void process  RequestBody com fasterxml jackson databind JsonNode payload            System out println payload

User · Answer

The issue appears with parsing the JSON from request body  tipical for an invalid JSON  If you re using curl on windows  try escaping the json like -d    name   value    or even -d      name     value       On the other hand you can ommit the content-type header in which case whetewer is sent will be converted to your String argument

User · Answer

I think the simplest handy way to consuming JSON is using a Java class that resembles your JSON  https   stackoverflow com a 6019761  But if you can t use a Java class you can use one of these two solutions   Solution 1  you can do it receiving a Map lt String  Object gt  from your controller    RequestMapping      value     process        method   RequestMethod POST  public void process  RequestBody Map lt String  Object gt  payload       throws Exception      System out println payload        Using your request   curl -H  Accept  application json  -H  Content-type  application json    -X POST -d    name   value    http   localhost 8080 myservice process     Solution 2  otherwise you can get the POST payload as a String    RequestMapping      value     process        method   RequestMethod POST      consumes    text plain   public void process  RequestBody String payload  throws Exception      System out println payload        Then parse the string as you want  Note that must be specified consumes    text plain  on your controller  In this case you must change your request with Content-type  text plain   curl -H  Accept  application json  -H  Content-type  text plain  -X POST   -d    name   value    http   localhost 8080 myservice process

User · Answer

To further work with array of maps  the followings could help    RequestMapping value     process   method   RequestMethod POST  headers    Accept application json   public void setLead  RequestBody Collection lt   extends Map lt String  Object gt  gt  payload  throws Exception      List lt Map lt String Object gt  gt  maps   new ArrayList lt Map lt String Object gt  gt       maps addAll payload

User · Answer

To add on to Andrea s solution  if you are passing an array of JSONs for instance          name   value          name   value2       Then you will need to set up the Spring Boot Controller like so    RequestMapping      value     process        method   RequestMethod POST  public void process  RequestBody Map lt String  Object gt    payload       throws Exception        System out println payload

[java] Trying to use Spring Boot REST to Read JSON String from POST

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