12.@Value读取配置文件及验证处理

 

@Value读取配置文件及验证处理

1. @Value

import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import lombok.Data;

@Component
@Data
public class Person {

	@Value("${person.id}")
	private Integer id;
	@Value("${person.user-name}")
	private String userName;
	@Value("${random.int(1,100)}")
	private Integer age;
	// @Value("${person.hobby}")
	private String[] hobby;
	private List<String> course;
	private Set<String> book;
	private Map<String, String> score;
    // @Value("${person.birthday.time}")
	private Date birthday;
	
}

package com.example.demo;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import com.example.demo.vo.Person;

@SpringBootTest
class SpringBoot007ApplicationTests {
	
	@Autowired
	private Person person;
	
	@Test
	public void testPerson() {
		System.out.println(person);
	}

}

output:

Person(id=2, userName=xiaozhang, age=77, hobby=[reading, exercise, writing], course=[literature, mathematics, geography, chemistry, biology], book=[book1, book2, book3, 2], score={math=90, chemistry=85}, birthday=Sun Jan 17 21:43:11 CST 2021)

2. 总结说明:

1，@Value只能注入简单类型的属性(基本数据类型和String)，其它的复杂类型是不能取到值的

2，如果属性是使用驼峰命名法则不能使用属性名注入，要使用@Value("${student.user-name}")来取值，不能使用@Value("${student.userName}")来取值

3. @Value和@ConfigurationProperties取值比较

项目	@ConfigurationProperties	@Value
功能	批量注入配置文件中的属性	一个一个指定
松散绑定(松散语法；驼峰命名法)	支持	不支持
SpEL(Spring的EL表达式)	不支持	支持
JSR303数据校验	支持	不支持
复杂类型封装	支持	不支持

@Value主动获取值，@ConfigurationProperties被动接收注入

SpEL: 例如#{2*10}

4. 验证处理

@Validated注解

@Email注解

pom.xml文件中加入依赖:

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

加入javax.validation依赖运行会报错

package com.example.demo.vo;

import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Set;

import javax.validation.constraints.Email;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
import org.springframework.validation.annotation.Validated;

import lombok.Data;

@Component
@ConfigurationProperties(prefix = "person")
@Data
@Validated
public class Person {

	private Integer id;
	private String userName;
	private Integer age;
	private String[] hobby;
	private List<String> course;
	private Set<String> book;
	private Map<String, String> score;
	private Date birthday;
	
	@Email
	private String email;
	
}

server:
  port: 8890

#config
person:
  id: 2
  user-name: xiaozhang
  age: ${random.int(1,100)}
  hobby:
  - reading
  - exercise
  - writing
  course:
  - literature
  - mathematics
  - geography
  - chemistry
  - ${course}
  book:
  - book1
  - book2
  - book3
  - ${person.id}
  score:
    math: 90
    chemistry: 85
  birthday:
    time: 1610890991736
  email: Jobs123@qq.com

course: biology

output:

Person(id=2, userName=xiaozhang, age=3, hobby=[reading, exercise, writing], course=[literature, mathematics, geography, chemistry, biology], book=[book1, book2, book3, 2], score={math=90, chemistry=85}, birthday=Sun Jan 17 21:43:11 CST 2021, email=Jobs123@qq.com)

如果使用给email注入的不是一个正确的邮箱会报错

Caused by: org.springframework.boot.context.properties.bind.validation.BindValidationException: Binding validation errors on person
   - Field error in object 'person' on field 'email': rejected value [Jobs123qq.com]; codes [Email.person.email,Email.email,Email.java.lang.String,Email]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [person.email,email]; arguments []; default message [email],[Ljavax.validation.constraints.Pattern$Flag;@23ee75c5,.*]; default message [不是一个合法的电子邮件地址]; origin class path resource [application.yml] - 29:10
	at org.springframework.boot.context.properties.bind.validation.ValidationBindHandler.validateAndPush(ValidationBindHandler.java:139) ~[spring-boot-2.4.2.jar:2.4.2]
...