Spring + React fetch data










1















i have a problem with fetch data from api exposed by spring.
I want to fetch data by:



componentDidMount() {
this.setState(isLoading: true);

fetch('http://localhost:8080/api/tasks/')
.then(response => return response.json() )
.then(results => this.setState(
tasks: results,
isLoading: false
));


The spring api which return data:



 @CrossOrigin(origins = "http://localhost:3000")
@GetMapping
public List<Task> findTasksByUserId()
return taskService.findTasksBelongToUser(idProvider.getCurrentUserId());



Returned JSON:



[

id: 1,
version: 0,
name: "Task1",
description: "description1",
priority: 1,
finished: true,
category:
id: 1,
version: 0,
name: "Uncategorized",
user:
id: 1,
version: 0,
login: "admin",
email: "admin@todo.pl",
enabled: true

,
user:
id: 1,
version: 0,
login: "admin",
email: "admin@todo.pl",
enabled: true
,
position: 0
,

id: 2,
version: 0,
name: "Task2",
description: "description2",
priority: 4,
finished: true,
category:
id: 1,
version: 0,
name: "Uncategorized",
user:
id: 1,
version: 0,
login: "admin",
email: "admin@todo.pl",
enabled: true

,
user:
id: 1,
version: 0,
login: "admin",
email: "admin@todo.pl",
enabled: true
,
position: 1
]


And i got a error like this:



Uncaught (in promise) SyntaxError: Unexpected token < in JSON at position 0


I dont know what is wrong but maybe format of json is not correct, because it's start with the sign '['.
I am a beginner in React so please about some hint and help.
regards










share|improve this question


























    1















    i have a problem with fetch data from api exposed by spring.
    I want to fetch data by:



    componentDidMount() {
    this.setState(isLoading: true);

    fetch('http://localhost:8080/api/tasks/')
    .then(response => return response.json() )
    .then(results => this.setState(
    tasks: results,
    isLoading: false
    ));


    The spring api which return data:



     @CrossOrigin(origins = "http://localhost:3000")
    @GetMapping
    public List<Task> findTasksByUserId()
    return taskService.findTasksBelongToUser(idProvider.getCurrentUserId());



    Returned JSON:



    [

    id: 1,
    version: 0,
    name: "Task1",
    description: "description1",
    priority: 1,
    finished: true,
    category:
    id: 1,
    version: 0,
    name: "Uncategorized",
    user:
    id: 1,
    version: 0,
    login: "admin",
    email: "admin@todo.pl",
    enabled: true

    ,
    user:
    id: 1,
    version: 0,
    login: "admin",
    email: "admin@todo.pl",
    enabled: true
    ,
    position: 0
    ,

    id: 2,
    version: 0,
    name: "Task2",
    description: "description2",
    priority: 4,
    finished: true,
    category:
    id: 1,
    version: 0,
    name: "Uncategorized",
    user:
    id: 1,
    version: 0,
    login: "admin",
    email: "admin@todo.pl",
    enabled: true

    ,
    user:
    id: 1,
    version: 0,
    login: "admin",
    email: "admin@todo.pl",
    enabled: true
    ,
    position: 1
    ]


    And i got a error like this:



    Uncaught (in promise) SyntaxError: Unexpected token < in JSON at position 0


    I dont know what is wrong but maybe format of json is not correct, because it's start with the sign '['.
    I am a beginner in React so please about some hint and help.
    regards










    share|improve this question
























      1












      1








      1








      i have a problem with fetch data from api exposed by spring.
      I want to fetch data by:



      componentDidMount() {
      this.setState(isLoading: true);

      fetch('http://localhost:8080/api/tasks/')
      .then(response => return response.json() )
      .then(results => this.setState(
      tasks: results,
      isLoading: false
      ));


      The spring api which return data:



       @CrossOrigin(origins = "http://localhost:3000")
      @GetMapping
      public List<Task> findTasksByUserId()
      return taskService.findTasksBelongToUser(idProvider.getCurrentUserId());



      Returned JSON:



      [

      id: 1,
      version: 0,
      name: "Task1",
      description: "description1",
      priority: 1,
      finished: true,
      category:
      id: 1,
      version: 0,
      name: "Uncategorized",
      user:
      id: 1,
      version: 0,
      login: "admin",
      email: "admin@todo.pl",
      enabled: true

      ,
      user:
      id: 1,
      version: 0,
      login: "admin",
      email: "admin@todo.pl",
      enabled: true
      ,
      position: 0
      ,

      id: 2,
      version: 0,
      name: "Task2",
      description: "description2",
      priority: 4,
      finished: true,
      category:
      id: 1,
      version: 0,
      name: "Uncategorized",
      user:
      id: 1,
      version: 0,
      login: "admin",
      email: "admin@todo.pl",
      enabled: true

      ,
      user:
      id: 1,
      version: 0,
      login: "admin",
      email: "admin@todo.pl",
      enabled: true
      ,
      position: 1
      ]


      And i got a error like this:



      Uncaught (in promise) SyntaxError: Unexpected token < in JSON at position 0


      I dont know what is wrong but maybe format of json is not correct, because it's start with the sign '['.
      I am a beginner in React so please about some hint and help.
      regards










      share|improve this question














      i have a problem with fetch data from api exposed by spring.
      I want to fetch data by:



      componentDidMount() {
      this.setState(isLoading: true);

      fetch('http://localhost:8080/api/tasks/')
      .then(response => return response.json() )
      .then(results => this.setState(
      tasks: results,
      isLoading: false
      ));


      The spring api which return data:



       @CrossOrigin(origins = "http://localhost:3000")
      @GetMapping
      public List<Task> findTasksByUserId()
      return taskService.findTasksBelongToUser(idProvider.getCurrentUserId());



      Returned JSON:



      [

      id: 1,
      version: 0,
      name: "Task1",
      description: "description1",
      priority: 1,
      finished: true,
      category:
      id: 1,
      version: 0,
      name: "Uncategorized",
      user:
      id: 1,
      version: 0,
      login: "admin",
      email: "admin@todo.pl",
      enabled: true

      ,
      user:
      id: 1,
      version: 0,
      login: "admin",
      email: "admin@todo.pl",
      enabled: true
      ,
      position: 0
      ,

      id: 2,
      version: 0,
      name: "Task2",
      description: "description2",
      priority: 4,
      finished: true,
      category:
      id: 1,
      version: 0,
      name: "Uncategorized",
      user:
      id: 1,
      version: 0,
      login: "admin",
      email: "admin@todo.pl",
      enabled: true

      ,
      user:
      id: 1,
      version: 0,
      login: "admin",
      email: "admin@todo.pl",
      enabled: true
      ,
      position: 1
      ]


      And i got a error like this:



      Uncaught (in promise) SyntaxError: Unexpected token < in JSON at position 0


      I dont know what is wrong but maybe format of json is not correct, because it's start with the sign '['.
      I am a beginner in React so please about some hint and help.
      regards







      json spring reactjs api






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 14 '18 at 18:18









      AdrianAdrian

      328




      328






















          1 Answer
          1






          active

          oldest

          votes


















          1














          fetch() returns a promise which gets resolved into an HTTP response of course, not the actual JSON. To extract the JSON body content from the response, we use the json() method.



          Try adding two headers Content-Type and Accept to be equal to application/json.



          fetch('http://localhost:8080/api/tasks/', 
          headers :
          'Content-Type': 'application/json',
          'Accept': 'application/json'


          )
          .then(response => return response.json() )
          .then(results => this.setState(
          tasks: results,
          isLoading: false
          ));





          share|improve this answer

























          • Ok, but now i have a problem with function map in this line tasks.map(task => ( <li key=task.id> task.name </li> ))

            – Adrian
            Nov 14 '18 at 18:38











          • what problem? If the tasks is an array map should work

            – Shivam
            Nov 14 '18 at 18:39












          • hmm that's weird because like i show above json is an array with objects

            – Adrian
            Nov 14 '18 at 18:40











          • If its array of objects then the function passed as argument to map will be executed for all objects in the array. Did you resolve your issue?

            – Shivam
            Nov 14 '18 at 18:43












          • No i am not yet, i dont't know why map doesnt fit

            – Adrian
            Nov 14 '18 at 18:46










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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          1














          fetch() returns a promise which gets resolved into an HTTP response of course, not the actual JSON. To extract the JSON body content from the response, we use the json() method.



          Try adding two headers Content-Type and Accept to be equal to application/json.



          fetch('http://localhost:8080/api/tasks/', 
          headers :
          'Content-Type': 'application/json',
          'Accept': 'application/json'


          )
          .then(response => return response.json() )
          .then(results => this.setState(
          tasks: results,
          isLoading: false
          ));





          share|improve this answer

























          • Ok, but now i have a problem with function map in this line tasks.map(task => ( <li key=task.id> task.name </li> ))

            – Adrian
            Nov 14 '18 at 18:38











          • what problem? If the tasks is an array map should work

            – Shivam
            Nov 14 '18 at 18:39












          • hmm that's weird because like i show above json is an array with objects

            – Adrian
            Nov 14 '18 at 18:40











          • If its array of objects then the function passed as argument to map will be executed for all objects in the array. Did you resolve your issue?

            – Shivam
            Nov 14 '18 at 18:43












          • No i am not yet, i dont't know why map doesnt fit

            – Adrian
            Nov 14 '18 at 18:46















          1














          fetch() returns a promise which gets resolved into an HTTP response of course, not the actual JSON. To extract the JSON body content from the response, we use the json() method.



          Try adding two headers Content-Type and Accept to be equal to application/json.



          fetch('http://localhost:8080/api/tasks/', 
          headers :
          'Content-Type': 'application/json',
          'Accept': 'application/json'


          )
          .then(response => return response.json() )
          .then(results => this.setState(
          tasks: results,
          isLoading: false
          ));





          share|improve this answer

























          • Ok, but now i have a problem with function map in this line tasks.map(task => ( <li key=task.id> task.name </li> ))

            – Adrian
            Nov 14 '18 at 18:38











          • what problem? If the tasks is an array map should work

            – Shivam
            Nov 14 '18 at 18:39












          • hmm that's weird because like i show above json is an array with objects

            – Adrian
            Nov 14 '18 at 18:40











          • If its array of objects then the function passed as argument to map will be executed for all objects in the array. Did you resolve your issue?

            – Shivam
            Nov 14 '18 at 18:43












          • No i am not yet, i dont't know why map doesnt fit

            – Adrian
            Nov 14 '18 at 18:46













          1












          1








          1







          fetch() returns a promise which gets resolved into an HTTP response of course, not the actual JSON. To extract the JSON body content from the response, we use the json() method.



          Try adding two headers Content-Type and Accept to be equal to application/json.



          fetch('http://localhost:8080/api/tasks/', 
          headers :
          'Content-Type': 'application/json',
          'Accept': 'application/json'


          )
          .then(response => return response.json() )
          .then(results => this.setState(
          tasks: results,
          isLoading: false
          ));





          share|improve this answer















          fetch() returns a promise which gets resolved into an HTTP response of course, not the actual JSON. To extract the JSON body content from the response, we use the json() method.



          Try adding two headers Content-Type and Accept to be equal to application/json.



          fetch('http://localhost:8080/api/tasks/', 
          headers :
          'Content-Type': 'application/json',
          'Accept': 'application/json'


          )
          .then(response => return response.json() )
          .then(results => this.setState(
          tasks: results,
          isLoading: false
          ));






          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Nov 15 '18 at 5:32

























          answered Nov 14 '18 at 18:28









          ShivamShivam

          1,1271231




          1,1271231












          • Ok, but now i have a problem with function map in this line tasks.map(task => ( <li key=task.id> task.name </li> ))

            – Adrian
            Nov 14 '18 at 18:38











          • what problem? If the tasks is an array map should work

            – Shivam
            Nov 14 '18 at 18:39












          • hmm that's weird because like i show above json is an array with objects

            – Adrian
            Nov 14 '18 at 18:40











          • If its array of objects then the function passed as argument to map will be executed for all objects in the array. Did you resolve your issue?

            – Shivam
            Nov 14 '18 at 18:43












          • No i am not yet, i dont't know why map doesnt fit

            – Adrian
            Nov 14 '18 at 18:46

















          • Ok, but now i have a problem with function map in this line tasks.map(task => ( <li key=task.id> task.name </li> ))

            – Adrian
            Nov 14 '18 at 18:38











          • what problem? If the tasks is an array map should work

            – Shivam
            Nov 14 '18 at 18:39












          • hmm that's weird because like i show above json is an array with objects

            – Adrian
            Nov 14 '18 at 18:40











          • If its array of objects then the function passed as argument to map will be executed for all objects in the array. Did you resolve your issue?

            – Shivam
            Nov 14 '18 at 18:43












          • No i am not yet, i dont't know why map doesnt fit

            – Adrian
            Nov 14 '18 at 18:46
















          Ok, but now i have a problem with function map in this line tasks.map(task => ( <li key=task.id> task.name </li> ))

          – Adrian
          Nov 14 '18 at 18:38





          Ok, but now i have a problem with function map in this line tasks.map(task => ( <li key=task.id> task.name </li> ))

          – Adrian
          Nov 14 '18 at 18:38













          what problem? If the tasks is an array map should work

          – Shivam
          Nov 14 '18 at 18:39






          what problem? If the tasks is an array map should work

          – Shivam
          Nov 14 '18 at 18:39














          hmm that's weird because like i show above json is an array with objects

          – Adrian
          Nov 14 '18 at 18:40





          hmm that's weird because like i show above json is an array with objects

          – Adrian
          Nov 14 '18 at 18:40













          If its array of objects then the function passed as argument to map will be executed for all objects in the array. Did you resolve your issue?

          – Shivam
          Nov 14 '18 at 18:43






          If its array of objects then the function passed as argument to map will be executed for all objects in the array. Did you resolve your issue?

          – Shivam
          Nov 14 '18 at 18:43














          No i am not yet, i dont't know why map doesnt fit

          – Adrian
          Nov 14 '18 at 18:46





          No i am not yet, i dont't know why map doesnt fit

          – Adrian
          Nov 14 '18 at 18:46



















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