Spring Boot 2.0 REST API 接口的数据验证

1.概要

在本Spring boot教程中,我们将学习如何验证发送到PUT/POST API请求的数据BODY。我们还将学习在API响应中添加自定义错误消息以提示错误。

1. HTTP POST /employees和请求正文不包含有效值或缺少一些字段。它将在响应主体中返回带有适当消息的HTTP状态代码400。
2. /employees/{id}请求中会发送HTTP GET 和INVALID ID。它会在响应主体中返回HTTP状态码404和正确的消息。

2.创建REST 模型和API类

@XmlRootElement(name = "employee")
@XmlAccessorType(XmlAccessType.FIELD)
public class EmployeeVO extends ResourceSupport implements Serializable
{
    private Integer employeeId;
    private String firstName;
    private String lastName;
    private String email;
 
    public EmployeeVO(Integer id, String firstName, String lastName, String email) {
        super();
        this.employeeId = id;
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }
 
    public EmployeeVO() {
    }
     
    //Removed setter/getter for readability
}

@PostMapping(value = "/employees")
public ResponseEntity<EmployeeVO> addEmployee (@RequestBody EmployeeVO employee)
{
    EmployeeDB.addEmployee(employee);
    return new ResponseEntity<EmployeeVO>(employee, HttpStatus.OK);
}
 
@GetMapping(value = "/employees/{id}")
public ResponseEntity<EmployeeVO> getEmployeeById (@PathVariable("id") int id)
{
    EmployeeVO employee = EmployeeDB.getEmployeeById(id);
     
    if(employee == null) {
         throw new RecordNotFoundException("Invalid employee id : " + id);
    }
    return new ResponseEntity<EmployeeVO>(employee, HttpStatus.OK);
}

3.应用请求验证和异常处理

@XmlRootElement(name = "employee")
@XmlAccessorType(XmlAccessType.FIELD)
public class EmployeeVO extends ResourceSupport implements Serializable
{
    private static final long serialVersionUID = 1L;
     
    public EmployeeVO(Integer id, String firstName, String lastName, String email) {
        super();
        this.employeeId = id;
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }
 
    public EmployeeVO() {
    }
 
    private Integer employeeId;
 
    @NotEmpty(message = "first name must not be empty")
    private String firstName;
 
    @NotEmpty(message = "last name must not be empty")
    private String lastName;
 
    @NotEmpty(message = "email must not be empty")
    @Email(message = "email should be a valid email")
    private String email;
     
    //Removed setter/getter for readability
}

自定义验证以添加有意义的信息

默认的弹簧验证工作，并提供有关错误的信息超载，这就是为什么你应该根据你的应用程序的需要定制它。您只能提供所需的错误信息，并且语句非常清晰。额外的信息也不建议。

建立有意义的例外并且足够好地描述问题始终是一个很好的建议。一种方法是创建单独的类来表示特定的业务用例失败，并在该用例失败时返回它们。

import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.ResponseStatus;
 
@ResponseStatus(HttpStatus.NOT_FOUND)
public class RecordNotFoundException extends RuntimeException
{
    public RecordNotFoundException(String exception) {
        super(exception);
    }
}

import java.util.List;
import javax.xml.bind.annotation.XmlRootElement;
 
@XmlRootElement(name = "error")
public class ErrorResponse
{
    public ErrorResponse(String message, List<String> details) {
        super();
        this.message = message;
        this.details = details;
    }
 
    //General error message about nature of error
    private String message;
 
    //Specific errors in API request processing
    private List<String> details;
 
    //Getter and setters
}

import java.util.ArrayList;
import java.util.List;
 
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.validation.ObjectError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.context.request.WebRequest;
import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
 
@SuppressWarnings({"unchecked","rawtypes"})
@ControllerAdvice
public class CustomExceptionHandler extends ResponseEntityExceptionHandler
{
    @ExceptionHandler(Exception.class)
    public final ResponseEntity<Object> handleAllExceptions(Exception ex, WebRequest request) {
        List<String> details = new ArrayList<>();
        details.add(ex.getLocalizedMessage());
        ErrorResponse error = new ErrorResponse("Server Error", details);
        return new ResponseEntity(error, HttpStatus.INTERNAL_SERVER_ERROR);
    }
 
    @ExceptionHandler(RecordNotFoundException.class)
    public final ResponseEntity<Object> handleUserNotFoundException(RecordNotFoundException ex, WebRequest request) {
        List<String> details = new ArrayList<>();
        details.add(ex.getLocalizedMessage());
        ErrorResponse error = new ErrorResponse("Record Not Found", details);
        return new ResponseEntity(error, HttpStatus.NOT_FOUND);
    }
 
    @Override
    protected ResponseEntity<Object> handleMethodArgumentNotValid(MethodArgumentNotValidException ex, HttpHeaders headers, HttpStatus status, WebRequest request) {
        List<String> details = new ArrayList<>();
        for(ObjectError error : ex.getBindingResult().getAllErrors()) {
            details.add(error.getDefaultMessage());
        }
        ErrorResponse error = new ErrorResponse("Validation Failed", details);
        return new ResponseEntity(error, HttpStatus.BAD_REQUEST);
    }
}

请求验证演示

1）HTTP GET / employees / 1 [有效]

HTTP Status : 200
 
{
    "employeeId": 1,
    "firstName": "firstName",
    "lastName": "lastName",
    "email": "email@gamil.com",
}

HTTP Status : 404
 
{
    "message": "Record Not Found",
    "details": [
        "Invalid employee id : 23"
    ]
}

请求参数：
{
    "lastName": "Bill",
    "email": "ibill@gmail.com"
}

响应结果:
HTTP Status : 400
 
{
    "message": "Validation Failed",
    "details": [
        "first name must not be empty"
    ]
}

请求参数:
{
    "email": "ibill@gmail.com"
}

响应结果：
HTTP Status : 400
 
{
    "message": "Validation Failed",
    "details": [
        "last name must not be empty",
        "first name must not be empty"
    ]
}

请求参数:
{
    "firstName":"Lokesh",
    "email": "ibill_gmail.com" //invalid email in request
}

响应内容:
HTTP Status : 400
 
{
    "message": "Validation Failed",
    "details": [
        "last name must not be empty",
        "email should be a valid email"
    ]
}

可用的注解

在上面的例子中，我们只使用了几个注释，如@NotEmpty和@Email。还有更多这样的注释来验证请求数据。需要时检查出来。

总结

1. 通过ID获取资源时验证ID。
2. 验证POST / PUT API中的请求主体字段。
3. 在API响应中发送一致且结构化的错误响应。

提示：项目源码下载demo-springboot2-rest-valid.zip

spring boot validate java

http://blog.xqlee.com/article/392.html