博客

1、引入依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-validation</artifactId>
</dependency>

2、编写字段

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
  
    @NotBlank(message = "姓名不能为空")
    private String name;
    
    private int age;
    
    @Pattern(regexp = "^[1][3|5|7|8][0-9]{9}$", message = "手机号格式有误")
    private String tel;
}

3、controller层添加@valid注解

@RequestMapping("/user")
@RestController
public class UserController {
    @PostMapping("/demo")
    public String demo(@RequestBody @Valid User u){
        System.out.println(u);
        return "ok";
    }
}

此时若是请求参数的姓名为空或者手机号格式不正确，则会抛出异常。

这样直接抛异常不太友好，可以通过@RestControllerAdvice处理全局异常，并将异常返回给前端。

4、定义全局异常类

@Slf4j
@RestControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(value = BindException.class)
    public JsonResult exceptionHandle(BindException exception) {

        BindingResult result = exception.getBindingResult();
        StringBuilder errorMsg = new StringBuilder();
        List<FieldError> fieldErrors = result.getFieldErrors();
        fieldErrors.forEach(error -> {
            log.error("field: " + error.getField() + ", msg:" + error.getDefaultMessage());
            errorMsg.append(error.getDefaultMessage()).append("!");
        });
        return JsonResult.fail(errorMsg.toString());
    }

    @ExceptionHandler(value = MethodArgumentNotValidException.class)
    public JsonResult MyExceptionHandle(MethodArgumentNotValidException exception) {

        BindingResult result = exception.getBindingResult();
        StringBuilder errorMsg = new StringBuilder();

        List<FieldError> fieldErrors = result.getFieldErrors();
        fieldErrors.forEach(error -> {
            log.error("field: " + error.getField() + ", msg:" + error.getDefaultMessage());
            errorMsg.append(error.getDefaultMessage()).append("!");
        });

        return JsonResult.fail(errorMsg.toString());
    }

    /**
     * 处理运行时异常
     * @param e
     * @return
     */
    @ExceptionHandler(RuntimeException.class)
    public JsonResult doHandleRuntimeException(RuntimeException e) {
        log.error(e.getMessage(), e);
        e.printStackTrace();
        return JsonResult.fail(e.getMessage());
    }
}

JsonResult.java为返回的json

@Data
public class JsonResult<T> {

    private Boolean success;

    private String message;

    private int code;

    private T data;

    /**
     * 操作成功
     * @param message
     * @param data
     * @return
     */
    public static JsonResult ok(String message,Object data){
        JsonResult result = new JsonResult();
        result.setSuccess(true);
        result.setMessage(message);
        result.setCode(200);
        result.setData(data);
        return result;
    }

    /**
     * 操作成功
     * @param message
     * @return
     */
    public static JsonResult ok(String message){
        JsonResult result = new JsonResult();
        result.setSuccess(true);
        result.setMessage(message);
        result.setCode(200);
        result.setData(null);
        return result;
    }

    /**
     * 操作失败
     * @param message
     * @return
     */
    public static JsonResult fail(String message){
        JsonResult result = new JsonResult();
        result.setSuccess(false);
        result.setMessage(message);
        result.setCode(500);
        result.setData(null);
        return result;
    }
}

此时若是输入错误的手机号则会返回相应的错误信息：

{
    "success": false,
    "message": "手机号格式有误!",
    "code": 500,
    "data": null
}

5、自定义注解（自定义校验规则）

1.编写注解

@Target({ ElementType.METHOD, ElementType.FIELD })
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = MyWordValidator.class)
public @interface MyValidator {

    String message();

    // groups 和 payload 这两个parameter 必须包含,不然会报错
    Class<?>[] groups() default {};

    Class<? extends Payload>[] payload() default {};
}

2.实现ConstraintValidator接口

public class MyWordValidator implements ConstraintValidator<MyValidator, Object> {
    @Override
    public boolean isValid(Object o, ConstraintValidatorContext constraintValidatorContext) {
        // 具体的校验规则,这里是字符长度小于等于10
        return o.toString().length() <= 10;
    }
}

3.使用注解

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {

    @NotBlank(message = "姓名不能为空")
    private String name;

    private int age;

    @Pattern(regexp = "^[1][3|5|7|8][0-9]{9}$", message = "手机号格式有误")
    private String tel;

    @MyValidator(message = "长度为10个字符以下")
    private String saying;
}

一些常用注解