错误：找不到类型为'object'的其他支持对象'[object Object]'。 NgFor仅支持绑定到Iterables，例如数组错误

Question

这是我的用户dto

@Entity
@Table(name="userr")
public class Userdata {
@Id
//@GeneratedValue(strategy=GenerationType.AUTO)
private int userid;
@Column(length=20)
private String username;

@OneToOne(targetEntity=Test.class,cascade=CascadeType.ALL,fetch=FetchType.EAGER)
@JoinColumn(name="testid", referencedColumnName="testId") 
private Test usertest;
@Size(min=3, max=20, message="password must be minimum 8 characters")
private String userPassword;
@Min(value=4)
private long userPhoneno;
@Email(message="enter proper email id")
private String userEmail;
@NotBlank(message="usertype cannot be empty")
private String userType;
//getters and setters

这是我的测试dto类

@Entity
@Table(name="test")
public class Test {
@Id
//@GeneratedValue(strategy=GenerationType.AUTO)
private int testId;
@Column(length=50)
private String testTitle;
@OneToMany(mappedBy="test")
private Set<Questions> testQuestions;
private int testTotalMarks;
private int testMarksScored;
//getter and setter

这是Question dto的

@Entity
@Table(name="questions")
public class Questions {
@Id
//@GeneratedValue(strategy=GenerationType.AUTO)
private int questionId;
@Column(length=100)
private String questionTitle;
@Column(length=30)
private String optionOne;
@Column(length=30)
private String optionTwo;
@Column(length=30)
private String optionThree;
@Column(length=30)
private String optionFour;
@Column(length=30)
private int rightAnswer;
@ManyToOne
@JoinColumn(name="testId")
private Test test;
@Column(length=30)
private int questionMarks;
@Column(length=30)
private int choosenAnswer;
@Column(length=30)
private int marksScored;
//getter and setter
}

我的jpa存储库查询

@Query("select t from Userdata u,Test t where u.usertest=t.testId and u.username=:username")
public Test get(@Param("username")String username);

这在邮递员中工作正常，但我在角度上出现错误我的控制器在春季启动]]

 @GetMapping("/username/{username}")
public Test getUserByName(@PathVariable(value="username") String username)
{
    return user.get(username);
}
我的service.ts以角度显示

getTestbyName(u:string): Observable<any>{
const headers =new HttpHeaders().set('Content_Type', 'text/plain ;charset=utf-8');
return this.httpService.get<Test>("http://localhost:8299/user/username/"+ u);
}
我使用此服务的用户home.ts

 username:string;
 test:Test[];
 constructor(private myservice: MyserviceService, private router: Router,
 private route:ActivatedRoute)
 {}
ngOnInit(): any {
let id=this.route.snapshot.paramMap.get('id');
this.username=id;
console.log(this.username);
this.myservice.getTestbyName(this.username).subscribe(
  response => this.handleSuccessfulResponse(response),
);
}
handleSuccessfulResponse(response) {
this.test = response;
console.log(response);
}
我尝试使用表打印值时，我的user-home.html没有显示并出现错误

<thead>
<tr>
    <th>Test ID</th>
    <th>Test Title</th>
    <th>Test Total Marks</th>
    <th>Test</th>
</tr>
</thead>
<tbody>
    <tr *ngFor="let e of test">
        <td> {{e.testId}} </td>
        <td> {{e.testTitle}} </td>
        <td> {{e.testTotalMarks}} </td>
     </tr>
</tbody>

我收到的错误：错误错误：找不到类型为“对象”的其他支持对象“ [对象对象]”。 NgFor仅支持绑定到Iterables，例如数组。

这是我的用户dto @Entity @Table（name =“ userr”）公共类Userdata {@Id //@GeneratedValue(strategy=GenerationType.AUTO）private int userid; @Column（length = 20）私有字符串用户名； @OneToOne（...

Answer 1

*ngFor适用于类似数组的集合。要循环对象，可以使用keyvalue管道。尝试以下]]

keyvalue