Question

希望这不是一个愚蠢的问题。连接ionic和java springboot时，当应用在浏览器中实时提供服务并且数据正确显示时，没有错误消息。但是出现了SyntaxError：在Android设备上进行测试时，JSON中的意外令牌<在JSON位置0处的JSON.parse（）错误。

我四处搜索，发现问题与JSON解析有关，但我不太理解为什么浏览器中未报告错误消息。

我想在这里做什么：我有一个具有用户名和电子邮件地址的用户表，我正在连接以在前端显示所有名称。后端返回一个列表。

我还使用了chrome CROS扩展名，但我认为这根本没有关系。有人可以帮忙解释一下吗？谢谢

   typescript
   ngOnInit() {
      this.surgeonList = [
      ];
      console.log(this.value);
      this.httpclient.get('http://localhost:8080/users'
      ).subscribe(
          data => {
              data = JSON.parse(JSON.stringify(data));
              for (var i  = 0 ; i < (<Array<any>>data).length; i++) {
                  this.surgeonList.push(
                      {
                          name: data[i].lastname,
                          icon: 'person'
                      }
                  );
              }
          }
      );
  }

JAVA spring controller

    @GetMapping("/users")
    public List getUsers(){
        List users = userRepository.findAll();
        return users;
    }

获取请求响应正确记录了数据：

[
    {
        "id": 2,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen698698@gmail.com",
        "password": "613387"
    },
    {
        "id": 3,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": null
    },
    {
        "id": 4,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": null
    },
    {
        "id": 5,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": null
    },
    {
        "id": 6,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": null
    },
    {
        "id": 7,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": "123333"
    },
    {
        "id": 8,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": "123333"
    },
    {
        "id": 9,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": "123333"
    },
    {
        "id": 10,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": "123333"
    },
    {
        "id": 11,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": "123333"
    },
    {
        "id": 12,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": "123333"
    },
    {
        "id": 13,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": "123333"
    },
    {
        "id": 14,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": "123333"
    },
    {
        "id": 15,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": "123333"
    },
    {
        "id": 16,
        "lastname": "Liu",
        "firstname": "Jerry",
        "email": "karen77777",
        "password": "123333"
    },
    {
        "id": 17,
        "lastname": "chenniuniu",
        "firstname": "Jerry",
        "email": "chenniuniu@gmail.com",
        "password": "613387"
    },
    {
        "id": 18,
        "lastname": "chendada",
        "firstname": "Jerry",
        "email": "chendaada@bobo.com",
        "password": "613387"
    },
    {
        "id": 19,
        "lastname": "chendada",
        "firstname": "Jerry",
        "email": "chendaada@bobo.com",
        "password": "613387"
    },
    {
        "id": 20,
        "lastname": "VFVSD",
        "firstname": "Jerry",
        "email": "DSFSDF",
        "password": "FDSFSDFDS"
    },
    {
        "id": 22,
        "lastname": "zhaohua liu",
        "firstname": "Jerry",
        "email": "zliu633@uwo.ca",
        "password": "613387"
    },
    {
        "id": 23,
        "lastname": null,
        "firstname": null,
        "email": "yche98@uwo.ca",
        "password": "613388"
    }
]

但是在chrome上进行远程检查时得到了

vendor.js:44729 ERROR 
HttpErrorResponse
error:
error: SyntaxError: Unexpected token < in JSON at position 0 at JSON.parse (<anonymous>) at XMLHttpRequest.onLoad

重新编辑：

谢谢你们的答复我是社区的新成员，你们是最棒的。

我发现这里有什么问题：

当我在浏览器上投放内容时，我发现响应作为json是正确的，就像你们所有人都说的那样。 response when serve on a browser

但是，当我部署该应用程序并在设备上对其进行远程测试时：我得到index.html作为响应： enter image description here

Answer 1

您似乎正在找回JSON对象，然后重新串化并解析它。那可能就是为什么？

   ngOnInit() {
      this.surgeonList = [
      ];
      console.log(this.value);
      this.httpclient.get('http://localhost:8080/users'
      ).subscribe(
          data => {
          this.surgeonList = data.map(doc=>{
          return {
              doc.lastname,
              icon: 'person'
            }
          })
              
              
          }
      );
  }

Answer 2

执行以下操作：将@ResponseBody放在您的控制器上

@GetMapping("/users")
@ResponseBody
public List getUsers(){
    List users = userRepository.findAll();
    return users;
}

OR

@GetMapping(value="/users",produces="application/json")
    @ResponseBody
    public List getUsers(){
        List users = userRepository.findAll();
        return users;
    }

或使用@RestController

取消您的课程

SyntaxError：XMLHttpRequest.onLoad中JSON.parse（<anonymous>）位置0处JSON中的意外令牌<

2 个答案: