目录

使用场景
1.对于controller入参字段检查
1）自定义注解
2）controller层检查UserDTO中包含List对象
3）检查UserDTO中 private List<String> strList，对其中字符串进行检查直接在List泛型上加检查注解
4）检查List<StudentDTO> 对象
5）对@RequestParam 字段检查

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2.springmvc全局异常统一处理

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1.对于controller入参字段检查

1）自定义注解

package cn.summit.validation.annotation;

import cn.summit.validation.validor.TextLengthValidator;

import javax.validation.Constraint;
import javax.validation.Payload;
import javax.validation.constraints.Min;
import java.lang.annotation.Documented;
import java.lang.annotation.Repeatable;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * 字符串长度检查
 *
 * @author summit
 * @since 2020/6/24 11:19
 */
@Target({METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE})
@Retention(RUNTIME)
@Repeatable(TextLength.List.class)
@Constraint(validatedBy = TextLengthValidator.class)
@Documented
public @interface TextLength {

    int min() default 0;

    int max() default Integer.MAX_VALUE;

    String message() default "{javax.validation.constraints.Length.message}";

    Class<?>[] groups() default {};

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

    /**
     * Defines several {@link Min} annotations on the same element.
     *
     * @see Min
     */
    @Target({METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE})
    @Retention(RUNTIME)
    @Documented
    @interface List {

        TextLength[] value();
    }
}

package cn.summit.validation.validor;

import cn.summit.validation.annotation.TextLength;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

/**
 * 字符串长度检查
 *
 * @author summit
 * @since 2020/6/24 11:19
 */
public class TextLengthValidator implements ConstraintValidator<TextLength, String> {

    private int min;

    private int max;

    @Override
    public void initialize(TextLength annotation) {
        this.min = annotation.min();
        this.max = annotation.max();
    }

    @Override
    public boolean isValid(String value, ConstraintValidatorContext context) {
        if (value == null) {
            return true;
        }
        int length = value.length();
        return length >= min && length <= max;
    }
}

2）controller层检查UserDTO中包含List对象

在其字段上加上@Valid，才会对List对象进行检查

public class UserDTO implements Serializable {
....
    @Valid
    private List<StudentDTO> studentList;

3）检查UserDTO中 private List<String> strList，对其中字符串进行检查

直接在List泛型上加检查注解

    private List< @TextLength(max = 3) String> strList;

4）检查List<StudentDTO> 对象

1.在controller上加上注解
2. public Result<String> test(@RequestBody @Valid List<UserDTO> list) {

5) 对@RequestParam 字段检查

1.需要在controller上加上 @Validated
    public void getTestVal(@PathVariable @TextLength(max = 5) String val) {

2.springmvc全局异常统一处理

@RestControllerAdvice
@Slf4j
public class GlobalBaseController implements ResponseBodyAdvice<Object> {

    /**
     * 用于处理通用异常
     */

    @ExceptionHandler(Throwable.class)
    public Result<?> errorHandler(Throwable e, HttpServletResponse response) {
        //  log.info("headers {}", headers);
        log.error("", e);
        return Result.failed("后台异常，请联系管理员");
    }

    /**
     * 用于处理通用异常 捕获 未加@RequestBody
     */
    @ExceptionHandler(BindException.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public Result<?> bindException(BindException e) {
        BindingResult bindingResult = e.getBindingResult();
        StringBuilder errorMesssage = new StringBuilder("校验失败:");

        for (FieldError fieldError : bindingResult.getFieldErrors()) {
            errorMesssage.append(fieldError.getField()).append(":")
                .append(fieldError.getDefaultMessage()).append(fieldError.getRejectedValue())
                .append("; ");
        }
        log.error(errorMesssage.toString());
        return Result.failed(errorMesssage.toString());
    }

    /**
     * 用于处理通用异常 捕获 @Validated UserDTO list
     */
    @ExceptionHandler(MethodArgumentNotValidException.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public Result<?> bindException(MethodArgumentNotValidException e) {
        BindingResult bindingResult = e.getBindingResult();
        StringBuilder errorMesssage = new StringBuilder("校验失败:");

        for (FieldError fieldError : bindingResult.getFieldErrors()) {

            errorMesssage.append(fieldError.getField()).append(":")
                .append(fieldError.getDefaultMessage()).append(fieldError.getRejectedValue())
                .append("; ");
        }
        log.error(errorMesssage.toString());
        return Result.failed(errorMesssage.toString());
    }

    /**
     * 用于处理通用异常
     *
     * 捕获 @RequestBody @Valid List<UserDTO> list 和 getTestVal(@PathVariable @TextLength(max = 5)
     * String val)
     */
    @ExceptionHandler(ConstraintViolationException.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public Result<?> bindException(ConstraintViolationException e) {
        Set<ConstraintViolation<?>> constraintViolations = e.getConstraintViolations();
        StringBuilder errorMesssage = new StringBuilder("校验失败:");
        for (ConstraintViolation<?> constraintViolation : constraintViolations) {
            errorMesssage.append(constraintViolation.getMessage());
            log.error(constraintViolation.getMessage());
        }
        return Result.failed(errorMesssage.toString());
    }