SpringBoot如何獲取application.properties中自定義的值

<?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 https://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>2.5.4</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.example</groupId>
	<artifactId>i18nSpringbootDemo-1</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>i18nSpringbootDemo-1</name>
	<description>Demo project for Spring Boot</description>
	<properties>
		<java.version>11</java.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
 
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		<!-- 導入配置文件處理器，配置文件進行綁定就會提示 -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-configuration-processor</artifactId>
			<optional>true</optional>
		</dependency>
		
		<!--校驗依賴-->
		<dependency>
		    <groupId>org.springframework.boot</groupId>
		    <artifactId>spring-boot-starter-validation</artifactId>
		</dependency>
	</dependencies>
 
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
 
	<packaging>war</packaging>
</project>

test.user.id=12
#也可以寫成 test.user.user-name=zhangsan
test.user.userName=zhansan
#也可以寫成 test.user.user-password=XXX
test.user.userPassword=PWD123
#也可以寫成 test.user.la-big-decimal=XXX
test.user.laBigDecimal=138.3
test.user.maps.key1=V1
test.user.maps.key2=123
test.user.lists=a12,a13,sdf
test.user.department.dep-code=dep001
test.user.department.dep-name=depName001

package com.example.demo.obj;
 
public class Department {
	private String depCode;
	private String depName;
	
	/**
	 * @return depCode
	 */
	public String getDepCode() {
		return depCode;
	}
	/**
	 * @param depCode セットする depCode
	 */
	public void setDepCode(String depCode) {
		this.depCode = depCode;
	}
	/**
	 * @return depName
	 */
	public String getDepName() {
		return depName;
	}
	/**
	 * @param depName セットする depName
	 */
	public void setDepName(String depName) {
		this.depName = depName;
	}
	@Override
	public String toString() {
		return "Department [depCode=" + depCode + ", depName=" + depName + "]";
	}
	
}

package com.example.demo.obj;
 
import java.math.BigDecimal;
import java.util.List;
import java.util.Map;
 
import javax.validation.constraints.Email;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
import org.springframework.validation.annotation.Validated;
 
/*
 * 將配置文件的每一個屬性值，映射到這個組件中:
 * ①@ConfigurationProperties：告訴SpringBoot將本類中的所有屬性和配置文件中相關的配置進行綁定；
 *     prefix = "test.user"：將配置文件中前綴為test.user下面的所有屬性進行一一映射
 *  隻有這個組件是容器中的組件，才能提供@ConfigurationProperties的功能，所以要加@Component
 * 
 * ②@Value("${key}")從環境變量、配置文件中獲取值
 * @Value("#{SpEl}")表達式
 * 
 * @ConfigurationProperties與@Value的區別：
 * @ConfigurationProperties支持松散語法，JSR303數據校驗，復雜類型封裝，不支持SpEL
 * @Value支持SpEL，不支持松散語法，JSR303數據校驗，復雜類型封裝
 * 如果說，我們在某個業務邏輯中需要獲取一下配置文件中的某項值，可以用@Value
 * 如果說，我們專門編寫瞭一個javaBean去和配置文件進行映射，我們直接使用@ConfigurationProperties
 */
@Component
@ConfigurationProperties(prefix = "test.user")
@Validated
public class User {
	//@Value("#{10*2}")
	private Integer id;
	//@Email userName必須輸入郵箱格式的值，要不然報錯
	//@Value("${test.user.userName}")
	private String userName;
	//@Value("${test.user.userPassword}")
	private String userPassword;
	//@Value("${test.user.laBigDecimal}")
	private BigDecimal laBigDecimal;
	
	//@Value("${test.user.maps}") X 不行會報錯
	private Map<String, Object> maps;
	//@Value("${test.user.lists}")
	private List<Object> lists;
	//@Value("${test.user.department}") X 不行會報錯
	private Department department;
	
	/**
	 * @return id
	 */
	public Integer getId() {
		return id;
	}
	/**
	 * @param id セットする id
	 */
	public void setId(Integer id) {
		this.id = id;
	}
	/**
	 * @return userName
	 */
	public String getUserName() {
		return userName;
	}
	/**
	 * @param userName セットする userName
	 */
	public void setUserName(String userName) {
		this.userName = userName;
	}
	/**
	 * @return userPassword
	 */
	public String getUserPassword() {
		return userPassword;
	}
	/**
	 * @param userPassword セットする userPassword
	 */
	public void setUserPassword(String userPassword) {
		this.userPassword = userPassword;
	}
	/**
	 * @return laBigDecimal
	 */
	public BigDecimal getLaBigDecimal() {
		return laBigDecimal;
	}
	/**
	 * @param laBigDecimal セットする laBigDecimal
	 */
	public void setLaBigDecimal(BigDecimal laBigDecimal) {
		this.laBigDecimal = laBigDecimal;
	}
	/**
	 * @return maps
	 */
	public Map<String, Object> getMaps() {
		return maps;
	}
	/**
	 * @param maps セットする maps
	 */
	public void setMaps(Map<String, Object> maps) {
		this.maps = maps;
	}
	/**
	 * @return lists
	 */
	public List<Object> getLists() {
		return lists;
	}
	/**
	 * @param lists セットする lists
	 */
	public void setLists(List<Object> lists) {
		this.lists = lists;
	}
	/**
	 * @return department
	 */
	public Department getDepartment() {
		return department;
	}
	/**
	 * @param department セットする department
	 */
	public void setDepartment(Department department) {
		this.department = department;
	}
	@Override
	public String toString() {
		return "User [id=" + id + ", userName=" + userName + ", userPassword=" + userPassword + ", laBigDecimal="
				+ laBigDecimal + ", maps=" + maps + ", lists=" + lists + ", department=" + department + "]";
	}
 
}

package com.example.demo;
 
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
 
/**
 * 應用啟動類
 *
 */
@SpringBootApplication
public class I18nSpringbootDemo1Application {
 
	public static void main(String[] args) {
		SpringApplication.run(I18nSpringbootDemo1Application.class, args);
	}
 
}

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.obj.User;
 
@SpringBootTest
class I18nSpringbootDemo1ApplicationTests {
	@Autowired
	User user;
	
	@Test
	void contextLoads() {
		System.out.println(user.toString());
	}
 
}