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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.hibernate.validator/hibernate-validator -->
        <dependency>
            <groupId>org.hibernate.validator</groupId>
            <artifactId>hibernate-validator</artifactId>
            <version>6.1.5.Final</version>
        </dependency>


        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.12</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

package com.ctvit.validatordemo.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.hibernate.validator.constraints.Length;

import javax.validation.constraints.Email;
import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.Pattern;
import java.io.Serializable;

/**
 * 用戶名，密碼，郵箱，身份證
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User implements Serializable {
    @NotEmpty(message="用戶名不能為空")
    @Length(min=6,max = 12,message="用戶名長(zhǎng)度必須位于6到12之間")
    private String userName;


    @NotEmpty(message="密碼不能為空")
    @Length(min=6,message="密碼長(zhǎng)度不能小于6位")
    private String passWord;

    @Email(message="請(qǐng)輸入正確的郵箱")
    private String email;

    @Pattern(regexp = "^(\\d{18,18}|\\d{15,15}|(\\d{17,17}[x|X]))$", message = "身份證格式錯(cuò)誤")
    private String idCard;

}

package com.ctvit.validatordemo.controller;

import com.ctvit.validatordemo.pojo.User;
import org.springframework.validation.BindingResult;
import org.springframework.validation.ObjectError;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.validation.Valid;
import java.util.List;

@RestController
public class UserController {

    @PostMapping("/Register")
    public String Register(@Valid User user, BindingResult bindingResult){//一個(gè)BindingResult對(duì)應(yīng)一個(gè)@Valid注解的參數(shù)，用來表示校驗(yàn)消息
        StringBuffer stringBuffer = new StringBuffer();//使用StringBuffer拼接錯(cuò)誤信息，比如用戶名為空，長(zhǎng)度等
        if(bindingResult.hasErrors()){//判讀是否攜帶錯(cuò)誤信息
            List<ObjectError> list =bindingResult.getAllErrors();//獲取所有錯(cuò)誤信息對(duì)象
            for (ObjectError objectError:list) {//遍歷對(duì)象，獲取錯(cuò)誤的具體信息
                //將所有信息進(jìn)行拼接
                stringBuffer.append(objectError.getDefaultMessage());
                stringBuffer.append("---");
            }
        }
        return stringBuffer!=null?stringBuffer.toString():"";//將錯(cuò)誤信息返回
    }
}