<span>spring-boot-starter-validation 校验参数</span>

spring-boot-starter-validation 校验参数

一、前言

本章介绍使用spring-boot-starter-validation 校验 SpringMVC 的入参。

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.5.2</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-validation</artifactId>
		</dependency>

二、常用注解

三、定义分组

用于分组校验。
使用场景，对同一个对象例如User(username , id) 在不同的接口时需要的校验规则不同。
例如，访问一个接口需要 username 不为null且长度大于0 ，id>=0 ；访问另一个接口需要 username 参数的长度在 [1,3]之间。

public class ValidateGroup {
    public interface FirstGroup {
    }

    public interface SecondeGroup {
    }

    public interface ThirdGroup {
    }
}

四、定义需要校验的对象

import javax.validation.constraints.Min;
import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.Size;
import lombok.Data;

@Data
public class User {
	@NotEmpty(message = "用户名不能为空")
	@Size(message = "用户名长度 [1-3] ", min = 1, max = 3,groups = ValidateGroup.FirstGroup.class)
	private String username;
	@Min(message = "id不得小于0", value = 0)
	private Integer id;

}

五、在handler 即 Controller中校验

import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.nbpicc.controller.ValidateGroup.FirstGroup;

@RestController
@RequestMapping("/")
public class TestController {

	@PostMapping("test3")
	public User test3(@RequestBody @Validated({ FirstGroup.class }) User u) {
		System.out.println(u);
		return u;
	}

	@PostMapping("test4")
	public User test4(@Validated User u) {
		System.out.println(u);
		return u;
	}

}

校验失败，会直接抛出异常。这样不太友好，可以使用@ControllerAdvice处理全局异常。

六、定义全局异常处理类

import java.util.List;
import org.springframework.validation.BindException;
import org.springframework.validation.BindingResult;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import lombok.extern.slf4j.Slf4j;

@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
	@ExceptionHandler(RuntimeException.class)
	public JsonResult doHandleRuntimeException(RuntimeException e) {
		log.error(e.getMessage(), e);
		e.printStackTrace();
		return JsonResult.fail(e.getMessage());
	}
}

另外JsonResult.java用于接口返回统一个json格式


import com.fasterxml.jackson.annotation.JsonInclude;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.experimental.Accessors;

/**
 *@author wang 
 *@Date 2020-9-14
 * 
 **/

@Data
@Accessors(chain = true)
@NoArgsConstructor
@AllArgsConstructor 
@JsonInclude(JsonInclude.Include.NON_NULL)
public class JsonResult<T>  {
		/** 成功 */	
		public static final int SUCCESS=200;
		/**内部服务器错误**/
		public static final int FAIL=500;
	    /** 没有登录 */
	    public static final int NOT_LOGIN = 400;
	    /** 发生异常 */
	    public static final int EXCEPTION = 401;
	    /** 系统错误 */
	    public static final int SYS_ERROR = 402;
	    /** 参数错误 */
	    public static final int PARAMS_ERROR = 403;
	    /** 不支持或已经废弃 */
	    public static final int NOT_SUPPORTED = 410;
	    /** AuthCode错误 */
	    public static final int INVALID_AUTHCODE = 444;
	    /** 太频繁的调用 */
	    public static final int TOO_FREQUENT = 445;
	    /** 未知的错误 */
	    public static final int UNKNOWN_ERROR = 499;
		
		private Integer code;  
        private String msg;
        private T data;
        
        public static JsonResult fail() {
            return new JsonResult(FAIL, "请求处理失败",null);
        }
        public static JsonResult fail(String msg) {
            return new JsonResult(FAIL, msg,null);
        }
        public static JsonResult fail(Integer code,String msg) {
            return new JsonResult(code, msg,null);
        }
        public static JsonResult success() {
            return new JsonResult(SUCCESS,"请求处理成功",null);
        }
        public static JsonResult success(String msg) {
            return new JsonResult(SUCCESS,msg,null);
        }
        public static <T> JsonResult success(T data) {
            return new JsonResult<T> (SUCCESS,"请求处理成功",data);
        }
        public static <T>  JsonResult success(String msg,T data) {
            return new JsonResult<T>(SUCCESS, msg,data);
        }
        

        
        public static JsonResult err() {
            return build(EXCEPTION);
        }
        public static JsonResult err(String msg) {
            return build(EXCEPTION, msg);
        }
        
	
        public JsonResult<T> code(int code) {
            this.code = code;
            return this;
        }
        public JsonResult<T> msg(String msg) {
            this.msg = msg;
            return this;
        }
        public JsonResult<T> data(T data) {
            this.data = data;
            return this;
        }
        
        
        public static JsonResult build() {
            return new JsonResult();
        }
        public static JsonResult build(int code) {
            return new JsonResult().code(code);
        }
        public static JsonResult build(int code, String msg) {
            return new JsonResult<String>().code(code).msg(msg);
        }
        public static <T> JsonResult<T> build(int code, T data) {
            return new JsonResult<T>().code(code).data(data);
        }
        public static <T> JsonResult<T> build(int code, String msg, T data) {
            return new JsonResult<T>().code(code).msg(msg).data(data);
        }
        
        
}

当然还有其他异常处理方式可以参考：
https://www.cnblogs.com/hujunzheng/p/9952563.html#autoid-0-0-0

七、测试效果

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八、嵌套对象的校验


import lombok.Data;

import javax.validation.Valid;
import javax.validation.constraints.*;

@Data
public class User {
    @NotEmpty(message = "用户名不能为空")
    @Size(message = "长度 [1-3] ", min = 1, max = 3, groups = ValidateGroup.FirstGroup.class)
    private String username;

    @Min(message = "id不得小于0", value = 0)
    private Integer id;
    
    @NotBlank(message = "地址不能为空", groups = {ValidateGroup.ThirdGroup.class, ValidateGroup.SecondeGroup.class})
    private String address;

    //在内部属性是自定义对象的时候添加 @Valid 注解 ，即可开启对In对象的校验。 
    //记得添加@NotNull注解，否则该对象可以为null，并且此时In对象的校验规则也不会抛出异常 。
    @Valid
    @NotNull(message = "In 对象不能为null ", groups = {ValidateGroup.ThirdGroup.class, ValidateGroup.SecondeGroup.class})
    private In in;
}

/**
 *自定义的对象，User对象中的一个属性。
 */
@Data
public class In {

    @NotBlank(message = "str不能为空", groups = {ValidateGroup.ThirdGroup.class, ValidateGroup.SecondeGroup.class})
    private String str;
}

九、自定义注解（自定义校验规则）

9.1 实现ConstraintValidator接口

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

public class WordConstraintValidator implements ConstraintValidator<CustomValidaor, Object> {
	@Override
	public boolean isValid(Object value, ConstraintValidatorContext context) {
		// 具体的校验规则
		return value.toString().length() == 10;
	}
}

9.2 自定义注解

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import javax.validation.Constraint;
import javax.validation.Payload;

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

	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 {};

}

9.3 使用

@Data
public class Inner {
	@NotBlank(message = "str不能为空", groups = { ValidateGroup.ThirdGroup.class, ValidateGroup.SecondeGroup.class })
	@CustomValidaor(message = "长度必须为10", groups = { ValidateGroup.ThirdGroup.class, ValidateGroup.SecondeGroup.class })
	private String str;
}