（九）springboot实战——springboot3下的webflux项目参数验证及其全局参数验证异常处理

前言

在上一节内容中，我们介绍了如何在webflux项目中自定义实现一个全局的异常处理器ErrorWebExceptionHandler，正常情况下其可以处理我们系统的运行时异常，但是无法处理参数验证的异常WebExchangeBindException，所以这里提供另外的全局异常处理方式，通过注解@ExceptionHandler实现参数验证的全局异常处理。

本节内容主要是实现webflux项目集成spring-boot-starter-validation验证框架，完成请求接口参数的后台验证，实现接口请求参数的统一验证处理，返回统一的响应数据格式。

正文

①引入请求参数验证框架spring-boot-starter-validation

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

②创建全局的参数验证异常处理器GlobalExceptionHandler

package com.yundi.atp.exception;

import com.yundi.atp.common.ApiResponse;
import com.yundi.atp.common.ErrorCode;
import lombok.extern.slf4j.Slf4j;
import org.springframework.validation.BindingResult;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import org.springframework.web.bind.support.WebExchangeBindException;
import reactor.core.publisher.Mono;

import java.util.List;

@Slf4j
@RestControllerAdvice
public class GlobalExceptionHandler {
    /**
     * 参数验证异常
     *
     * @param ex
     * @return
     */
    @ExceptionHandler(WebExchangeBindException.class)
    public Mono<ApiResponse> handleWebExchangeBindException(WebExchangeBindException ex) {
        log.info("参数验证异常:" + ex);
        // 处理绑定异常
        BindingResult result = ex.getBindingResult();
        List<FieldError> fieldErrors = result.getFieldErrors();
        return Mono.just(ApiResponse.fail(ErrorCode.WEB_EXCHANGE_BIND_ERROR.getCode(), fieldErrors.get(0).getDefaultMessage()));
    }

    /**
     * 数学计算异常
     *
     * @param ex
     * @return
     */
    @ExceptionHandler(ArithmeticException.class)
    public Mono<ApiResponse> handleArithmeticException(ArithmeticException ex) {
        log.info("数学计算异常:" + ex);
        return Mono.just(ApiResponse.fail(ErrorCode.ARITHMETIC_ERROR.getCode(), ErrorCode.ARITHMETIC_ERROR.getMsg()));
    }

    /**
     * 自定义异常
     *
     * @param ex
     * @return
     */
    @ExceptionHandler(MyException.class)
    public Mono<ApiResponse> handleMyException(MyException ex) {
        log.info("自定义异常：" + ex);
        return Mono.just(ApiResponse.fail(ex.getCode(), ex.getMessage()));
    }

    /**
     * 兜底异常
     *
     * @param ex
     * @return
     */
    @ExceptionHandler(Exception.class)
    public Mono<ApiResponse> handleMyException(Exception ex) {
        log.info("系统异常：" + ex);
        return Mono.just(ApiResponse.fail(ErrorCode.SYSTEM_ERROR.getCode(), ErrorCode.SYSTEM_ERROR.getMsg()));
    }
}

③ ErrorCode统一定义错误码，方便根据相关错误码处理业务

package com.yundi.atp.common;


public enum ErrorCode {
    SYSTEM_ERROR(10000, "系统错误!"),
    ARITHMETIC_ERROR(10001, "数学计算异常！"),
    WEB_EXCHANGE_BIND_ERROR(10002, "参数验证异常！"),
    ;


    private Integer code;
    private String msg;

    ErrorCode(Integer code, String message) {
        this.code = code;
        this.msg = message;
    }

    public Integer getCode() {
        return code;
    }

    public void setCode(Integer code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }
}

④以新增用户数据为例，增加用户数据的验证

package com.yundi.atp.entity;

import io.swagger.v3.oas.annotations.media.Schema;
import jakarta.validation.constraints.NotBlank;
import jakarta.validation.constraints.NotNull;
import lombok.Data;
import org.springframework.data.annotation.Id;
import org.springframework.data.relational.core.mapping.Table;


@Schema(name = "User", description = "用户类")
@Table(name = "user")
@Data
public class User {
    @Id
    @Schema(name = "id", description = "用户ID")
    private Integer id;

    @NotBlank(message = "用户名称不得为空！")
    @Schema(name = "name", description = "用户名称")
    private String name;

    @NotNull(message = "用户年龄不得为空！")
    @Schema(name = "age", description = "用户年龄")
    private Integer age;
}

⑤在保存用户请求接口中使用@Valid注解，开启请求参数验证

⑥ 启动webflux应用，使用swagger工具测试保存用户接口，验证参数注解生效，并按照统一响应格式返回了数据

⑦ 验证用户年龄的参数不为空

⑧ swagger需要使用专属webflux的springdoc-openapi-starter-webflux-ui启动器

<!-- https://mvnrepository.com/artifact/org.springdoc/springdoc-openapi-starter-webflux-ui -->
<dependency>
	<groupId>org.springdoc</groupId>
	<artifactId>springdoc-openapi-starter-webflux-ui</artifactId>
	<version>2.3.0</version>
</dependency>