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How does the SpringBoot interface verify parameters?

王林forward: 2023-05-22 20:49:321265browse

什么是不优雅的参数校验

后端对前端传过来的参数也是需要进行校验的，如果在controller中直接校验需要用大量的if else做判断

以添加用户的接口为例，需要对前端传过来的参数进行校验，如下的校验就是不优雅的：

@RestController
@RequestMapping("/user")
public class UserController {
@PostMapping("add")
public ResponseEntity<String> add(User user){
if(user.getName()==null) {
return ResponseResult.fail("user name should not be empty");
} else if(user.getName().length()<5 || user.getName().length()>50){
return ResponseResult.fail("user name length should between 5-50");
}
if(user.getAge()< 1 || user.getAge()> 150) {
return ResponseResult.fail("invalid age");
}
// ...
return ResponseEntity.ok("success");
}
}

针对这个普遍的问题，Java开者在Java API规范 (JSR303) 定义了Bean校验的标准validation-api，但没有提供实现。

hibernate validation是对这个规范的实现，并增加了校验注解如@Email、@Length等。

Spring Validation是对hibernate validation的二次封装，用于支持spring mvc参数自动校验。

接下来，我们以springboot项目为例，介绍Spring Validation的使用。

实现案例

本案例使用了 Spring Validation 对参数绑定进行了验证，主要为您提供参数验证的思路。请参考SpringBoot如何封装接口统一错误信息处理，其中包括针对绑定参数检查错误的处理

POM

添加pom依赖:

<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-validation -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>

请求参数封装

单一职责，所以将查询用户的参数封装到UserParam中，而不是User（数据库实体）本身。

对每个参数字段添加validation注解约束和message。

/**
* user.
*
* @author pdai
*/
@Data
@Builder
@ApiModel(value = "User", subTypes = {AddressParam.class})
public class UserParam implements Serializable {
private static final long serialVersionUID = 1L;
@NotEmpty(message = "could not be empty")
private String userId;
@NotEmpty(message = "could not be empty")
@Email(message = "invalid email")
private String email;
@NotEmpty(message = "could not be empty")
@Pattern(regexp = "^(\\d{6})(\\d{4})(\\d{2})(\\d{2})(\\d{3})([0-9]|X)$", message = "invalid ID")
private String cardNo;
@NotEmpty(message = "could not be empty")
@Length(min = 1, max = 10, message = "nick name should be 1-10")
private String nickName;
@NotEmpty(message = "could not be empty")
@Range(min = 0, max = 1, message = "sex should be 0-1")
private int sex;
@Max(value = 100, message = "Please input valid age")
private int age;
@Valid
private AddressParam address;
}

Controller中获取参数绑定结果

使用@Valid或者@Validate注解，参数校验的值放在BindingResult中

/**
* @author pdai
*/
@Slf4j
@Api(value = "User Interfaces", tags = "User Interfaces")
@RestController
@RequestMapping("/user")
public class UserController {

/**
* http://localhost:8080/user/add .
*
* @param userParam user param
* @return user
*/
@ApiOperation("Add User")
@ApiImplicitParam(name = "userParam", type = "body", dataTypeClass = UserParam.class, required = true)
@PostMapping("add")
public ResponseEntity<String> add(@Valid @RequestBody UserParam userParam, BindingResult bindingResult){
if (bindingResult.hasErrors()) {
List<ObjectError> errors = bindingResult.getAllErrors();
errors.forEach(p -> {
FieldError fieldError = (FieldError) p;
log.error("Invalid Parameter : object - {},field - {},errorMessage - {}", fieldError.getObjectName(), fieldError.getField(), fieldError.getDefaultMessage());
});
return ResponseEntity.badRequest().body("invalid parameter");
}
return ResponseEntity.ok("success");
}
}