Spring Boot读取配置的5种方式

妖狐艹你老母 2021-11-16 22:06 305阅读 0赞

## 作者：Java技术栈   链接：https://www.jianshu.com/p/982e36f42c67   来源：简书 ##

## 读取application文件 ##

在application.yml或者properties文件中添加：

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

> ### @Value注解读取方式 ###

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注解读取方式 ###

@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;
        }
    
    }

## 读取指定文件 ##

资源目录下建立config/db-config.properties:

db.username=root  
db.password=123456

> ### @PropertySource+@Value注解读取方式 ###

@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文件读取。

> ### @PropertySource+@ConfigurationProperties注解读取方式 ###

@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;
        }
    
    }

> ### Environment读取方式 ###

以上所有加载出来的配置都可以通过Environment注入获取到。

@Autowired
    private Environment env;
    
    // 获取参数
    String getProperty(String key);

## 总结 ##

从以上示例来看，Spring Boot可以通过@PropertySource,@Value,@Environment,@ConfigurationProperties来绑定变量。