Springboot整合Hibernate Validator实现对自定义报文CommonRequest内容参数校验

1、什么是validator？

在开发中经常需要写一些字段校验的代码，比如字段非空，字段长度限制，邮箱格式验证等等，写这些与业务逻辑关系不大的代码有三个麻烦：

   验证代码繁琐，重复劳动
   方法内代码显得冗长
   每次要看哪些参数验证是否完整，需要去翻阅验证逻辑代码

Hibernate Validator就用于解决这种问题，他是一种参数校验的框架， Bean Validation 的参考实现 . Hibernate Validator 提供了 JSR 303规范中所有内置 constraint 的实现，除此之外还有一些附加的 constraint。

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2、准备工作

(1) Springboot项目中，它被集成在web包里

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

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(2) 编写校验结果存储类(存储错误信息)

import org.apache.tomcat.util.buf.StringUtils;

import java.util.HashMap;
import java.util.Map;

public class ValidationResult {
    private boolean hasErrors;
    private Map<String,String> errorMsgMap = new HashMap<>();

    public boolean isHasErrors() {
        return hasErrors;
    }

    public void setHasErrors(boolean hasErrors) {
        this.hasErrors = hasErrors;
    }

    public Map<String, String> getErrorMsgMap() {
        return errorMsgMap;
    }

    public void setErrorMsgMap(Map<String, String> errorMsgMap) {
        this.errorMsgMap = errorMsgMap;
    }

    //通过字符串信息获取错误结果的msg方法
    public String getErrMsg(){
        return errorMsgMap.toString();
    }

}

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(3) 编写ValidatorImpl实现类，实现错误检查，并且将错误结果存储在ValidationResult

import org.springframework.beans.factory.InitializingBean;
import org.springframework.stereotype.Component;

import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.Validator;
import java.util.Set;

@Component
public class ValidatorImpl implements InitializingBean {

    private Validator validator;

    public ValidationResult validate(Object bean){
        ValidationResult validationResult = new ValidationResult();
        Set<ConstraintViolation<Object>> constraintViolationSet = validator.validate(bean);
        if(constraintViolationSet.size() > 0){
        //大于0说明有错误
            validationResult.setHasErrors(true);
            constraintViolationSet.forEach(constraintViolation->{
                String errMsg = constraintViolation.getMessage();
                String propertyName = constraintViolation.getPropertyPath().toString();
                validationResult.getErrorMsgMap().put(propertyName,errMsg);
            });
        }
        return validationResult;
    }
    @Override
    public void afterPropertiesSet() throws Exception {
        //将validator通过工厂的初始化方式使其实例化
        this.validator = Validation.buildDefaultValidatorFactory().getValidator();
    }
}

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(4) 实体类，注意其中部分属性上的注解

import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;

import javax.persistence.Id;
import javax.validation.constraints.NotNull;
import java.io.Serializable;
import java.util.Date;
/**
 * dictionaryDTO
 * 
 * @Date: 2019/8/13
 * @Version: 1.0
 * @Maintenance Records:
 */
public class DictionaryVO implements Serializable {

    private static final long serialVersionUID = 6193674149029494679L;
    /**
     * 字典id
     */
    @Id
    @JsonSerialize(using = ToStringSerializer.class)
    private Long dictionaryId;
    /**
     * 字典名
     */
    @NotNull(message = "字典名不能为空！")
    private String name;
    /**
     * 字典类型
     */
    @NotNull(message = "字典类型不能为空！")
    private String category;
    /**
     * 字典值
     */
    @NotNull(message = "字典值不能为空！")
    private String value;
    /**
     * 更新时间
     */
    private Date updatedTime;
    /**
     * 备注
     */
    private String remark;
    /**
     * 状态
     */
    @Max(1)
	@Min(0)
    private Integer status;


    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getCategory() {
        return category;
    }

    public void setCategory(String category) {
        this.category = category;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    public Date getUpdatedTime() {
        return updatedTime;
    }

    public void setUpdatedTime(Date updatedTime) {
        this.updatedTime = updatedTime;
    }

    public String getRemark() {
        return remark;
    }

    public void setRemark(String remark) {
        this.remark = remark;
    }

    public Integer getStatus() {
        return status;
    }

    public void setStatus(Integer status) {
        this.status = status;
    }

    public Long getDictionaryId() {
        return dictionaryId;
    }

    public void setDictionaryId(Long dictionaryId) {
        this.dictionaryId = dictionaryId;
    }

    @Override
    public String toString() {
        return "DictionaryVO{" +
                "dictionaryId=" + dictionaryId +
                ", name='" + name + '\'' +
                ", category='" + category + '\'' +
                ", value='" + value + '\'' +
                ", updatedTime=" + updatedTime +
                ", remark='" + remark + '\'' +
                ", status=" + status +
                '}';
    }
}

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(5) ！在Springboot启动器上加上扫描我们validator包的注解，使其能够找到我们的validator实现类

@EnableAspectJAutoProxy
@SpringBootApplication(scanBasePackages ={"utils.validator"})
@MapperScan(basePackages ="com.bosssoft.bes.basedata.center.dao")
public class ApiApplication {

    public static void main(String[] args) {
        SpringApplication.run(ApiApplication.class, args);
    }

}

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(6) Controller上的方法，其余代码就不贴出来了，看看主要方法部分

/**
 * 数据字典添加
 *
 * @param commonRequest
 * @return: protocol.CommonResponse
 */
@Override
@RequestMapping(value = "add",method = RequestMethod.POST)
public CommonResponse add(@RequestBody  CommonRequest commonRequest) {
    //用fastJson将前端传回来的Json转成我们要的对象，注意下面的方法是自定义的工具，读者可以自行百度方法
    DictionaryVO dictionaryVO = (DictionaryVO) Converter.getObjectFromJson(JSON.toJSONString(commonRequest.getBody()),DictionaryVO.class);

    //采用validator验证
    ValidationResult result = validator.validate(dictionaryVO);
    if(result.isHasErrors()){
        //这里面存的就是错误信息,本来应该抛异常，这里直接返回给前端信息
        result.getErrMsg();
        return CommonResponse.create("1","1","1",false,result.getErrMsg());
    }

    dictionaryService.add(dictionaryVO);
    return CommonResponse.create("1","2","3",false,"添加成功！");
}

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3、简单用PostMan测试下

 {
    "head": {
        "version": "1",
        "token": "1",
        "businessType": "1",
        "deviceId": "1",
        "deviceType": "0",
        "encrypt": "false"
    },
    "body": {
    	"data": {
    		"dictionaryId": "8",
    		"name": "8",
	        "category": "8",
	        "value": "8",
	        "remark": "8",
	        "status": "7",
	        "createdBy": "11",
	        "createdTime": "2019-08-15 18:21:24",
	        "updatedBy": "11",
	        "updatedTime": "2019-08-15 18:21:24",
	        "version": "2"
    	}
       
    }
}

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4、测试

可以看到，我们的控制器检验了代码并返回了我们所需要错误信息

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5、小结

通过上述使用Validator进行参数校验的实例，可以看出它减少了我们平常繁琐且重复的校验过程，极大降低后端参数校验代码的冗余度~