Spring Boot讀取配置的幾種方式

       當大家看到這篇博客的時候 ，相信已經對SpringBoot有了簡單的瞭解。也看過很多人的demo，但是會發現 不同的程序員 在獲取配置信息時 使用的方式不一樣，不免會搞得一頭霧水,下面我們來一起看一下 具體有哪些方式。

1.讀取application文件

在application.yml或者properties文件中添加：

info.address=USA
info.company=Spring
info.degree=high

@Value註解讀取方式

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
 
@Component
public class InfoConfig1 {
 
   @Value("${info.address}")
   private String address;
 
   @Value("${info.company}")
   private String company;
 
   @Value("${info.degree}")
   private String degree;
 
   public String getAddress() {
       return address;
   }
 
   public void setAddress(String address) {
       this.address = address;
   }
 
   public String getCompany() {
       return company;
   }
 
   public void setCompany(String company) {
       this.company = company;
   }
 
   public String getDegree() {
       return degree;
   }
 
   public void setDegree(String degree) {
       this.degree = degree;
   }
 
}

@ConfigurationProperties註解讀取方式

@Component
@ConfigurationProperties(prefix = "info")
public class InfoConfig2 {
 
   private String address;
   private String company;
   private String degree;
 
   public String getAddress() {
       return address;
   }
 
   public void setAddress(String address) {
       this.address = address;
   }
 
   public String getCompany() {
       return company;
   }
 
   public void setCompany(String company) {
       this.company = company;
   }
 
   public String getDegree() {
       return degree;
   }
 
   public void setDegree(String degree) {
       this.degree = degree;
   }
 
}

2.讀取指定文件

資源目錄下建立config/db-config.properties:

db.username=root
db.password=123456

2.1@PropertySource+@Value註解讀取方式

@Component
@PropertySource(value = { "config/db-config.properties" })
public class DBConfig1 {
 
   @Value("${db.username}")
   private String username;
 
   @Value("${db.password}")
   private String password;
 
   public String getUsername() {
       return username;
   }
 
   public void setUsername(String username) {
       this.username = username;
   }
 
   public String getPassword() {
       return password;
   }
 
   public void setPassword(String password) {
       this.password = password;
   }
 
}

注意：@PropertySource不支持yml文件讀取。

2.2 @PropertySource+@ConfigurationProperties註解讀取方式

@Component
@ConfigurationProperties(prefix = "db")
@PropertySource(value = { "config/db-config.properties" })
public class DBConfig2 {
 
   private String username;
   private String password;
 
   public String getUsername() {
       return username;
   }
 
   public void setUsername(String username) {
       this.username = username;
   }
 
   public String getPassword() {
       return password;
   }
 
   public void setPassword(String password) {
       this.password = password;
   }
 
}

3. Environment讀取方式

以上所有加載出來的配置都可以通過Environment注入獲取到。

@Autowired
private Environment env;
 
// 獲取參數
String getProperty(String key);

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