spring-boot之注解参数校验以及话术渲染问题 【BindingResult】

源码地址

​​https://gitee.com/gaoxinfu_admin/open-source/blob/master/spring/spring-framework-5.0.2.RELEASE-%E4%B8%AD%E6%96%87%E6%B3%A8%E9%87%8A%E7%89%88/demo-spring-context/src/main/java/com/gaoxinfu/demo/spring/context/validation/BindingResultDemo.java​​

pom.xml依赖

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.2.5.RELEASE</version>
  </parent>

  <groupId>com.gaoxinfu.demo.spring.context</groupId>
  <artifactId>demo-spring-context</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>demo-spring-context Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>

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

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
    </dependency>
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
    </dependency>
  </dependencies>

  <build>
    <finalName>demo-spring-context</finalName>
    <plugins>
    <plugin>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-maven-plugin</artifactId>
    </plugin>
  </plugins>
  </build>
</project>

BindingResultDemo

package com.gaoxinfu.demo.spring.context.validation;

import lombok.Data;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.validation.BindingResult;
import org.springframework.validation.annotation.Validated;
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 javax.validation.constraints.*;
import java.math.BigDecimal;

/**
 * @Description:
 * @Author: gaoxinfu
 * @Date: 2021-01-13 10:56
 * @see BindingResult
 */
@RestController
@RequestMapping(path = "/BindingResult")
public class BindingResultDemo {

  @PostMapping(path = "/sayHello")
  public String sayhello(@Validated @RequestBody Greeting greeting, BindingResult greetingBindingResult){
    if (greetingBindingResult.hasErrors()){
      return "参数校验不通过:"+greetingBindingResult.getFieldError().getDefaultMessage();
    }
    return "参数校验通过";
  }
}


@Data
class Greeting {

  @NotBlank(message = "name姓名字段不能为空")
  private String name;

  /**
   * @Digits
   * integer:此数字接受的最大整数位数
   * fraction:小数位数接受的最大位数
   *
   * 从下到上执行验证
   */
  @Digits(message = "得分分数只能是2位整数，并且不能有小数", integer =2 , fraction =0 )
  @NotNull(message = "score不能为空")
  private BigDecimal score;

  @Max(value = 100,message = "最大年龄不能超过100岁")
  @Min(value = 18,message = "最小年龄不能超过18岁")
  @NotNull(message = "age不能为空")
  private Integer age;

  @Email(message = "邮箱格式不正确")
  @NotBlank(message = "邮箱不能为空")
  private String email;

  @DateTimeFormat(pattern ="yyyy-MM-dd")
  @NotBlank(message = "出生日期不能为空")
  private String birthDate;
}

解析

定义Greeting

1.我们对应Greeting这个对象里的每个字段进行了注解，这里的注解实际上是一个参数校验的过程，那么这个参数校验是如何生效的呢？
  实际上是通过BindingResultDemo.sayhello方法中的@Validated(我们也可以用 javax.validation.Valid 即@Valid)去触发校验，
  一般@Validated与BindingResult是组合使用，BindingResult实际上是接收参数校验的一个结果
2.我们通过  BindingResult里的FieldError去获取失败的原因

请求样例